Exercise, Health & You: How Much Is Enough?

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Exercise, Health & You: How Much Is Enough?

Postby JeffN » Wed Jun 25, 2014 11:56 am

Exercise, Health and You: How Much Is Enough?
Jeff Novick, MS, RDN

While optimal health requires a certain level of activity, exercise and fitness, more exercise does not always equal greater health, and too much exercise can lead to less than optimal health.

While maintaining a certain level of adequate strength (and muscle) is important for a long disability-free life, there are things athletes do to maximize performance in the short-term that are counter productive to maximizing their health for the long-term. For example, they may have to engage in unhealthy dietary practices to meet their needs for extra calories. They also may have to spend unreasonable amounts of time training, which increases their risk for activity related injuries.

Optimal short-term sports and/or athletic performance does not always equate to optimal long-term health.

My approach to fitness is the same as to food: simple, common sense, safe and sane. Just as I do not encourage extreme forms of eating, I do not encourage extreme forms of exercise.

Let's put this in proper context and perspective...

Only 23% of Americans meet the minimum requirements for exercise (aerobic and resistance) (1) and, on any given day, only 5% of Americans engage in vigorous activity (2). Over half of Americans do not meet the minimum requirements of exercise and almost 30% are considered completely sedentary (3). This sedentary behavior and the lack of exercise contribute to many of our leading preventable causes of premature disability and death. That means that, for over 80% of the population, the most important goal is to be active enough to meet at least the minimum requirements. My goal is to get the 80% active enough to reap the health benefits, not to get them to become extreme athletes or body builders, or to engage in high-level competitive sports.

That is the message—not one of supplements, protein powders, gimmicks, gadgets, potions, pills, food industry trends, dietary fads, exercise gimmicks, extreme eating or extreme exercise—but a common sense diet and a common sense amount of activity each day with no extreme forms of eating or exercise.

How much is enough?

The best recommendations come from recognized, credible fitness/health organizations. Find their recommendations at the following links (and find a quick summary below):

American College of Sports Medicine
https://journals.lww.com/acsm-msse/Full ... ng.26.aspx

Centers For Disease Control and Prevention
http://www.cdc.gov/physicalactivity/eve ... dults.html

American Heart Association
http://www.heart.org/HEARTORG/GettingHe ... rticle.jsp

World Health Organization
http://www.who.int/dietphysicalactivity ... adults/en/

The U.S. Department of Health and Human Services (HHS)
https://www.hhs.gov/fitness/be-active/p ... index.html

The Office of Disease Prevention and Health Promotion
http://www.health.gov/paguidelines/guid ... pter4.aspx

American Council on Exercise
http://www.acefitness.org/acefit/fitnes ... cise-tips/

National Health Services UK
http://www.nhs.uk/Livewell/fitness/Page ... dults.aspx

USDA 2015 Dietary Guidelines Exercise Recommendations
https://health.gov/dietaryguidelines/20 ... ppendix-1/

American Institute of Cancer Research
http://www.aicr.org/reduce-your-cancer- ... -activity/

You can sum this all up by simply saying: Aim for 30-60 minutes per day, most days of the week (4-6), which will depend on intensity, and will include both aerobic and resistance training. Another way to look at it is, 150 to 300 minutes per week. The inclusion of some balance and flexibility work is also recommended.

I do not know of any doctor in this field who recommends more than these guidelines as part of any of these programs.

Which is the best exercise? The one you will do. :)

For most of us, brisk walking along with some resistance training is more than enough. However, if you enjoy another form, just pick the one you enjoy and will do, regardless of whether it is walking, jogging, running, swimming, cycling, exercise classes, etc.

In Health,

We can also look at the issue another way, which I have discussed many times before. Let us say we have two identical people.

- one maintains a BMI of 18.5 and does so through a very healthy diet. They exercise moderately about 30 minutes a day, 5x a week and burn a total of about 2000 calories per day. To maintain their BMI, they consume about 2000 calories per day.

- the other identical person also maintains a BMI of 18.5 and does so through a very healthy diet. However, they exercise vigorously about 1.5 - 2 hours a day (or more) and burn a total of about 3000-3500 calories per day. To maintain their BMI, they consume about 3000-3500 calories per day.

The studies in animals and the recent ones in humans show the first one will do much better and live longer and healthier.

Remember, a little is good, a little more may be a little better, but not that much and lots more is not good.

My recommendations are...

1) Follow the guidelines & principles as recommended in this forum, especially in the sticky The Healthy Eating Placemat.

2) Follow the guidelines & principles for exercise/activity as recommended above, which include 150 minute to 300 minutes a week with a focus on aerobic & resistance with some stretching and flexibility.

3) If weight is an issue, or the regular program is not working, strictly follow the Maximum Weight Loss (MWL) program and if needed, the principles on how to fine tune the MWL.

4) In certain instances, (i.e., persistent symptoms, autoimmune disease, etc) an elimination diet may be required to eliminate any hidden triggers.

5) For those interested in "Calorie Restriction with Optimal Nutrition" (CR), use the above principles in point 1, 2 & 3 to maintain a BMI of 18.5-22

6) Get proper sleep, rest, relaxation, pure air, pure water, have a passion, surround yourself with loving relationships & most of all, relax & enjoy life.

In Health

(1) State Variation in Meeting the 2008 Federal Guidelines for Both Aerobic and Muscle-strengthening Activities Through Leisure-time Physical Activity Among Adults Aged 18–64: United States, 2010–2015. National Health Statistics Reports, Number 112, June 28, 2018

(2) Frequently Reported Activities by Intensity for U.S. Adults: The American Time Use Survey.
American Journal of Preventive Medicine Volume 39, Issue 4 , Pages e13-e20, October 2010

(3) Physical Activity Council. 2014 Participation Report.

On the problems with extreme exercise.

(if you only do one thing, watch the at the bottom of this post in point #7, which sums of most everything.)

1) Extreme Workouts: When Exercise Does More Harm than Good

http://healthland.time.com/2012/06/04/e ... than-good/

http://www.sciencedaily.com/releases/20 ... 093108.htm

"recent research suggests that chronic training for, and competing in, extreme endurance exercise such as marathons, iron man distance triathlons, and very long distance bicycle races may cause structural changes to the heart and large arteries, leading to myocardial injury. A study in the June issue of Mayo Clinic Proceedingsreviews the literature and outlines in detail for the first time the mechanisms, pathophysiology, and clinical manifestations of cardiovascular injury from excessive endurance exercise."

2) The results of 3 very large studies reviewed here in the NY Times.

http://well.blogs.nytimes.com/2012/06/0 ... -exercise/

3) Potential Adverse Cardiovascular Effects From Excessive Endurance Exercise. Mayo Clinic Proceedings. Volume 87, Issue 6 , Pages 587-595, June 2012

http://www.mayoclinicproceedings.org/ar ... 25-6196(12)00473-9/fulltext

A routine of regular exercise is highly effective for prevention and treatment of many common chronic diseases and improves cardiovascular (CV) health and longevity. However, long-term excessive endurance exercise may induce pathologic structural remodeling of the heart and large arteries. Emerging data suggest that chronic training for and competing in extreme endurance events such as marathons, ultramarathons, ironman distance triathlons, and very long distance bicycle races, can cause transient acute volume overload of the atria and right ventricle, with transient reductions in right ventricular ejection fraction and elevations of cardiac biomarkers, all of which return to normal within 1 week. Over months to years of repetitive injury, this process, in some individuals, may lead to patchy myocardial fibrosis, particularly in the atria, interventricular septum, and right ventricle, creating a substrate for atrial and ventricular arrhythmias. Additionally, long-term excessive sustained exercise may be associated with coronary artery calcification, diastolic dysfunction, and large-artery wall stiffening. However, this concept is still hypothetical and there is some inconsistency in the reported findings. Furthermore, lifelong vigorous exercisers generally have low mortality rates and excellent functional capacity. Notwithstanding, the hypothesis that long-term excessive endurance exercise may induce adverse CV remodeling warrants further investigation to identify at-risk individuals and formulate physical fitness regimens for conferring optimal CV health and longevity.

4) Three articles at this link

http://www.msma.org/docs/communications ... dicine.pdf

A) Increased Coronary Artery Plaque Volume Among Male Marathon Runners
Missouri Medicine | March/April 2014 | 111:2 | 85


Long-term marathon running improves many cardiovascular risk factors, and is presumed to protect against coronary artery plaque formation. This hypothesis, that long-term marathon running is protective against coronary atherosclerosis, was
tested by quantitatively assessing coronary artery plaque using high resolution coronary computed tomographic angiography (CCTA) in veteran marathon runners compared to sedentary control subjects.

Men in the study completed at least one marathon yearly for 25 consecutive years. All study subjects underwent CCTA, 12-lead electrocardiogram, measurement of blood pressure, heart rate, and lipid panel. A sedentary matched group was derived from a contemporaneous CCTA database of asymptomatic healthy individuals. CCTAs were analyzed using validated plaque characterization software.

Male marathon runners (n = 50) as compared with sedentary male controls (n = 23) had increased total plaque volume (200 vs. 126 mm3, p < 0.01), calcified plaque volume (84 vs. 44 mm3, p < 0.0001), and non-calcified plaque volume (116 vs. 82 mm3, p = 0.04). Lesion area and length, number of lesions per subject, and diameter stenosis did not reach statistical significance.

Long-term male marathon runners may have paradoxically increased coronary artery plaque volume.

B) Coronary Artery Plaque and Cardiotoxicity as a Result of Extreme Endurance Exercise
Missouri Medicine | March/April 2014 | 111:2 | 91

C) Pheidippides’ Final Words:“My Feet Are Killing Me!”
by John C. Hagan, III, MD
"In the long run, you may end up with a broken heart:
Missouri Medicine | March/April 2014 | 111:2 | 95

5) There May Be Such a Thing as 'Too Much Exercise'
Research suggests that moderate activity might be best for people with pre-existing heart disease
By Robert Preidt

http://www.webmd.com/fitness-exercise/n ... h-exercise

WEDNESDAY, May 14, 2014 (HealthDay News) -- Is there a limit to the benefits of exercise? Two studies suggest that, for certain people, keeping to a moderate physical activity regimen may be best for heart health.

One study found that a schedule of intense workouts actually boosted the risk of death from heart attack or stroke in older people with pre-existing heart disease, while the other found that young men who did a lot of endurance exercise were at higher risk for heart rhythm problems later in life.

However, one expert unconnected to the studies stressed that, on the whole, exercise is good medicine.

"Folks with heart disease should continue to engage in some form of daily physical activity," urged Barbara George, director of The Center for Cardiovascular Lifestyle Medicine at Winthrop-University Hospital in Mineola, N.Y. But she said moderation is key.

"You shouldn't feel you have to become a marathon runner to reap the benefits," George said.

The first study was led by Dr. Ute Mons of the German Cancer Research Center in Heidelberg, Germany, and included more than 1,000 people. Most of the participants were in their 60s, had stable heart disease and were tracked for 10 years. About 40 percent exercised two to four times a week, 30 percent worked out more often, and 30 percent exercised less often.

Compared to those who got regular exercise, the most inactive people were about twice as likely to have a heart attack or stroke, and were about four times more likely to die of heart disease and all causes, the researchers said.

However, Mons' team also found that those who did the most strenuous daily exercise were more than twice as likely to die of a heart attack compared to those who exercised more moderately.

The second study was led by Dr. Nikola Drca of the Karolinska Institute in Stockholm, Sweden, and included more than 44,000 Swedish men, aged 45 to 79. All of the men were asked about their physical activity levels at ages 15, 30, 50 and during the previous year. Their heart health was then tracked for an average of 12 years.

Those who had done intensive exercise for more than five hours a week when they were younger were 19 percent more likely to have developed a heart rhythm disorder called atrial fibrillation by age 60 than those who exercised for less than an hour a week.

That risk increased to 49 percent among those who did more than five hours of exercise at age 30 but did less than an hour a week by the time they were 60. Participants who cycled or walked briskly for an hour or more a day at age 60 were 13 percent less likely to develop atrial fibrillation.

The studies were published online May 14 in the journal Heart.

Another expert said the findings shouldn't alter standard recommendations.

"It is not standard practice to recommend strenuous activity to individuals with coronary heart disease," said Dr. Nieca Goldberg, director of the Tisch Center for Women's Health at NYU Langone Medical Center, New York City. "This study, although interesting, does not change current recommendations for moderate physical activity in coronary patients."

For her part, George said it's clear that a moderate exercise program can provide real benefit for everyone.

"A large body of scientific research has consistently shown that a sedentary lifestyle is one of the risk factors for cardiovascular disease, which includes heart disease, and that becoming more physically active can decrease your risk by as much as 50 percent," she said.

Current American Heart Association guidelines advise 30 minutes of moderate-intensity aerobic exercise most days a week or 20 minutes of vigorous activity three days a week, George added.

And in a journal editorial, a team led by Dr. Lluis Mont of the Hospital Clinic of Barcelona, Spain, agreed with the two U.S. experts.

"The benefits of exercise are definitely not to be questioned; on the contrary, they should be reinforced," the team wrote. But studies like the two published in Heart are fine-tuning recommendations for exercise, to "maximize benefits obtained by regular exercise while preventing undesirable effects -- just like all other drugs and therapies," the editorialists said.

6) A reverse J-shaped association of leisure time physical activity with prognosis in patients with stable coronary heart disease: evidence from a large cohort with repeated measurements.
Heart. 2014 May 14. pii: heartjnl-2013-305242. doi: 10.1136/heartjnl-2013-305242. [Epub ahead of print]

http://heart.bmj.com/content/early/2014 ... 2.abstract


OBJECTIVE: To study the association of self-reported physical activity level with prognosis in a cohort of patients with coronary heart disease (CHD), with a special focus on the dose-response relationship with different levels of physical activity.

METHODS: Data were drawn from a prospective cohort of 1038 subjects with stable CHD in which frequency of strenuous leisure time physical activity was assessed repeatedly over 10 years of follow-up. Multiple Cox proportional hazards regression models were used to assess the association of physical activity level with different outcomes of prognosis (major cardiovascular events, cardiovascular mortality, all-cause mortality), with different sets of adjustments for potential confounders and taking into account time-dependence of frequency of physical activity.

RESULTS: A decline in engagement in physical activity over follow-up was observed. For all outcomes, the highest hazards were consistently found in the least active patient group, with a roughly twofold risk for major cardiovascular events and a roughly fourfold risk for both cardiovascular and all-cause mortality in comparison to the reference group of moderately frequent active patients. Furthermore, when taking time-dependence of physical activity into account, our data indicated reverse J-shaped associations of physical activity level with cardiovascular mortality, with the most frequently active patients also having increased hazards (2.36, 95% CI 1.05 to 5.34).

CONCLUSIONS: This study substantiated previous findings on the increased risks for adverse outcomes in physically inactive CHD patients. In addition, we also found evidence of increased cardiovascular mortality in patients with daily strenuous physical activity, which warrants further investigation.

7) Run for your life! At a comfortable pace, and not too far:
James O'Keefe at TEDxUMKC


"The fitness patterns for conferring longevity and robust lifelong cardiovascular health are distinctly different from the patterns that develop peak performance and marathon/superhuman endurance. Extreme endurance training and racing can take a toll on your long-term cardiovascular health. For the daily workout, it may be best to have more fun endure less suffering in order to attain ideal heart health."

Dr. James O'Keefe Jr. is the director of Preventative Cardiology Fellowship Program and the Director of Preventative Cardiology at Cardiovascular Consultants at the Saint Luke's Mid America Heart Institute, a large cardiology practice in Kansas City. He is the co-author of four bestselling books including The Forever Young Diet & Lifestyle (Andrews McMeel Publishing LLC, 2005). In 1989, he became a professor of medicine at the University of Missouri - Kansas City and has contributed to over 200 articles in medical literature. He is also the chief medical officer and founder of Cardiotabs, a company that creates nutritional supplements to aid in a healthy lifestyle.

8 ) There is also an increase in activity related risks. In regard to running, excessive and improper running can cause injuries. However, light running (running in moderation, at an eight- to 10-minute mile pace, for about 40 minutes a few days a week) can be beneficial.

http://www.npr.org/2011/03/28/134861448 ... your-knees
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Re: Exercise, Health & You: How Much Is Enough?

Postby Ltldogg » Wed Jun 25, 2014 1:25 pm


I love how you look at the whole picture and the whole of valid, available Science. Your work and effort are having such a positive impact on my life and others. Keep it up and Thank You for everything!

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Re: Exercise, Health & You: How Much Is Enough?

Postby Acura » Wed Jun 25, 2014 1:32 pm

JeffN wrote:My approach to fitness is the same as to food. Simple, common sense, safe and sane. Just as I do not encourage extreme forms of eating, I do not encourage extreme forms of exercise.

It is good to know that you don't need to do unnatural, extraordinary things to lead a healthy and vibrant life. What's the point in eating like a queens and Kings first and then driving to Gym to workout for 20-30 mins which is not enough anyway no matter how fast you run after eating 500-1000 calories more than you should.

Some moving such as gardening, walking, biking, some weight lifting, some yoga other moderate exercises may be all that is necessary. It's good to know that finally some studies corroborate that we don't need to go nuts over this. What is not sustainable, what is not natural can't be the necessity. Nature/evolution won't do this to us.

If we are eating 2000-2500 calories, the majority of the calorie deficit has to come from there. Not from 200-300 daily average calories that you burn by exercising.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Wed Jun 25, 2014 1:46 pm

LynnCS wrote: OMG, Jeff...Thank you. At 75 and the healthiest I've been in a very long time, I am finding walking on the treadmill several times a day and light weight strength workout to be optimum, yet am told to do more.

We live in a world where we think "more" is always better. I can't think of one situation in regard to diet, exercise or health, where once one has achieved an adequate amount, where more is better. Just the opposite.

Sadly, many people, even in the WFPB world are being misled by this and some of it by actual messages being sent by those seen as leaders in the movement. Let me give two examples

1) Last week, I spoke with someone who was not doing well at achieving their goals. When we reviewed their intake, they were consuming several high calorie, high protein vegan shakes a day, which were easily contributed to some of their problems. I said that these were not recommended at all. Their response was, they went to an WFPB event and one of the speakers was an extreme athlete. After the event, they looked the person up and saw they were also a "teacher" at one of the WFPB online courses. So, they went to the website and saw they sold these protein shakes and being they were vegan and being the person was a speaker at one of the events sponsored by one of the "known" programs, they figured they were ok to use. I said, well first, they are extreme athletes and so have the ability to consume way more calories than you or I. While I would not recommend those calories come in the form of a high calorie, high protein shake, they can at least get away with those extra calories, at least in regard to weight. While you can outrun the excess calories of a bad diet, you can not out run the negative health implications, which may take time, even decades to see. However, for this person, who is just doing a regular amount of exercise, if even that, the calories are way too much for them.

2) Almost the exact same exact scenario as above. However, this time, I was contacted because the person was not just not getting well, they were getting worse. Much worse. Their weight was going up and their blood sugars were getting worse. When we reviewed their intake, same thing... they were consuming these protein shakes along with protein bars, etc, throughout the day that were being recommended by a different extreme athlete. They said, they say many of the doctors had endorsed the book the person wrote and so thought their recommendations and recommended products were ok.

I understand the problem of "association" and that because these people have often spoken at events and/or have books out with endorsements, that they are being seen as blessed. I wish that these issues were clarified to the audience so we do not have these "mix-ups" as the message they have is coming from a different place and for a different audience.

Remember, lets keep things in perspective... the majority of Americans are sedentary and just need to get active and that alone, will have a major impact on their health. The majority of people who come to the WFPB movement do so because they are fairly sick if not seriously ill. Most are not in training for a marathon looking for a few tips to maximize their performance, but are barely active, if at all. So, having a 45-55 year old female who is overweight, diabetic with heart disease, follow some of their recommendations and use their products, will not be helpful to them.

This is why we have to go directly to the "horses mouth" and not someone who is giving you their version of it. In the above examples, outside of being extreme athletes, neither of them had any health professional qualifications.

If someone wants to be an extreme athlete or body builder, that is up to them, but it is not a part of the "health" program recommended here, nor is it required to be healthy, and it may not be in their best interest over the long term for their optimal health.

LynnCS wrote: I have learned so much about living a basic, simple, healthy food life from you, and look forward to even more understanding of how be in the best shape possible. This is a turning point for me to be able to go into the next years and stay strong. Words cannot express how much I benefit from all you and the McDougall team do. So grateful that you all put yourself out there for those of us who might not have heard or known what to do. In spite of books, this interaction is priceless.

Thank you.

LynnCS wrote: Looking forward to reading all the details of your new adventure.

What new adventure?

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Re: Exercise, Health & You: How Much Is Enough?

Postby molly25 » Wed Jun 25, 2014 2:00 pm

What about intensive overexercise in the past? I did it all - triathlons, ultras, marathons, ultra swims. :( My knees won't take high impact anymore so I stick to walking, swimming, Pilates, and some weight training, but could there be permanent inflammatory damage (other than to joints, I mean). Os is it like nutrition, where if you "clean up" your exercise act and tone it down to moderate levels, it stabilizes or reverses any damage?
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Wed Jun 25, 2014 2:02 pm

molly25 wrote:What about intensive overexercise in the past? I did it all - triathlons, ultras, marathons, ultra swims. :( My knees won't take high impact anymore so I stick to walking, swimming, Pilates, and some weight training, but could there be permanent inflammatory damage (other than to joints, I mean). Os is it like nutrition, where if you "clean up" your exercise act and tone it down to moderate levels, it stabilizes or reverses any damage?

Watch the video in the last section of the post. He shows evidence of reversal.

I was a extreme athlete and used to run marathons. I stopped many years ago when I first started seeing the evidence.

What was, was. :)

The best each and any of us can do now, is to do the right thing each and every day.

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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Wed Jun 25, 2014 3:53 pm

Thanks for the comments.

Im going to close the thread. Feel free to start a new one if you have a question.

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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Tue Jul 15, 2014 10:47 am

Here are two other concepts that I have discussed in this forum before, that can really help people in meeting the minimum requirements. They will provide enormous benefit with little to no risk and do not take a lot of time or effort.

1) Sitting, Standing & Intermittent Walking
http://www.jeffnovick.com/RD/Q_%26_As/E ... lking.html


2) NEAT - Non Exercise Activity Thermogenesis

This is defined as little movements throughout the day such as fidgeting, tapping, standing instead of sitting, crossing one legs, etc. They have found these can add up and can account for upwards of 300 calories a day or more.

The “NEAT Defect” in Human Obesity:
The Role of Nonexercise Activity Thermogenesis
volume 2 number 1 2007

http://www.mayoclinic.org/documents/mc5 ... c-20079082

Non-Exercise Activity Thermogenesis
The Crouching Tiger Hidden Dragon of Societal Weight Gain
Arteriosclerosis, Thrombosis, and Vascular Biology.
2006; 26: 729-736


These are the messages that have to get out to the public as they will provide enormous benefit with little to no risk and do not take a lot of time or effort and are 100% inline with our overall message.

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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Tue Jul 15, 2014 1:41 pm

I think this visual may help put this in perspective.

In this study, they looked at physical activity and mortality from six prospective cohort studies comprising 654,827 individuals, 21–90 y of age. Physical activity was categorized by metabolic equivalent hours per week (MET-h/wk).

Leisure Time Physical Activity of Moderate to Vigorous Intensity and Mortality: A Large Pooled Cohort Analysis
Published: November 06, 2012DOI: 10.1371/journal.pmed.1001335

http://www.plosmedicine.org/article/inf ... ed.1001335

As we can see, there is a real "diminishing return" on the impact of the increased exercise and activity and while the higher categories do have an increase benefit, the benefit gets smaller with each category of increased effort you go up with the least benefit in going from 20-30 METs.


And, as you can see again, most all the benefit comes in hitting the 10 METs per week goal


If you look through the charts, you will also see the least benefit of the extra exercise is to those who are the "Healthy Non Smokers."

If you want to know more about MET's and MET-h/wk, this article will help.
http://www.health.gov/paguidelines/guid ... ndix1.aspx

As a general guide, someone achieving the 150 minutes at week at a moderate intensity (or 75 minutes per week at a vigorous intensity) is at about 10 METs per week.

Someone achieving the 300 minutes per week at a moderate intensity (or 150 minutes per week at a vigorous intensity) is around 20 METs per week.

So 30 MET's would be about 450 minutes of moderate intensity (or 225 minutes per week or 45 minutes per day at a vigorous intensity).

Many extreme athletes train way (way) more then this.

Clearly, being active within the recommended guidelines (30-60 minutes per day or 10-20 MET hours per week) is of great benefit over being sedentary. In fact, going from sedentary to the recommended minimums (about 10 MET hours per week), gives you the greatest improvement for your efforts. But how much more benefit, if any, are you getting for all that extra time and effort surpassing them and at what cost

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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Wed Aug 13, 2014 8:44 am

1) Contrary to Popular Belief, More Exercise Is Not Always Better. One in Twenty People May be Overdoing Exercise,
Mayo Clinic Proceedings

Press Release from Mayo Clinic Proceedings

http://www.mayoclinicproceedings.org/pb ... 89_8_3.pdf

Rochester, MN, August 12, 2014 – There is strong epidemiological evidence of the importance of regular physical activity, such as brisk walking and jogging, in the management and rehabilitation of cardiovascular disease and in lowering the risk of death from other diseases such as hypertension, stroke, and type 2 diabetes. The Physical Activity Guidelines for Americans recommends about 150 minutes per week of moderate-intensity exercise or about 75 minutes of vigorous-intensity exercise. But there is clear evidence of an increase in cardiovascular deaths in heart attack survivors who exercise to excess, according to a new study published in Mayo Clinic Proceedings.

2) Increased Cardiovascular Disease Mortality Associated With Excessive Exercise in Heart Attack Survivors
Published Online: August 12, 2014
DOI: http://dx.doi.org/10.1016/j.mayocp.2014.05.006


To test whether greater exercise is associated with progressively lower mortality after a cardiac event.

Patients and Methods
We used Cox proportional hazard analyses to examine mortality vs estimated energy expended by running or walking measured as metabolic equivalents (3.5 mL O2/kg per min per day or metabolic equivalent of task-h/d [MET-h/d]) in 2377 self-identified heart attack survivors, where 1 MET-h/d is the energy equivalent of running 1 km/d. Mortality surveillance via the National Death Index included January 1991 through December 2008.

A total of 526 deaths occurred during an average prospective follow-up of 10.4 years, 376 (71.5%) of which were related to cardiovascular disease (CVD) (International Statistical Classification of Diseases, 10th Revision codes I00-I99). CVD-related mortality compared with the lowest exercise group decreased by 21% for 1.07 to 1.8 MET-h/d of running or walking (P=.11), 24% for 1.8 to 3.6 MET-h/d (P=.04), 50% for 3.6 to 5.4 MET-h/d (P=.001), and 63% for 5.4 to 7.2 MET-h/d (P<.001) but decreased only 12% for ≥7.2 MET-h/d (P=.68). These data represent a 15% average risk reduction per MET-h/d for CVD-related mortality through 7.2 MET-h/d (P<.001) and a 2.6-fold risk increase above 7.2 MET-h/d (P=.009). Relative to the risk reduction at 7.2 MET-h/d, the risk for ≥7.2 MET-h/d increased 3.2-fold (P=.006) for all ischemic heart disease (IHD)–related mortalities but was not significantly increased for non–IHD-CVD, arrhythmia-related CVD, or non–CVD-related mortalities.

Running or walking decreases CVD mortality risk progressively at most levels of exercise in patients after a cardiac event, but the benefit of exercise on CVD mortality and IHD deaths is attenuated at the highest levels of exercise (running: above 7.1 km/d or walking briskly: 10.7 km/d).

3) Exercising for Health and Longevity vs Peak Performance: Different Regimens for Different Goals
Published Online: August 12, 2014
DOI: http://dx.doi.org/10.1016/j.mayocp.2014.07.007


Everything in excess is opposed to nature.

Accumulating evidence suggests that exercise practices that are ideal for promoting health and longevity may differ from the high-volume, high-intensity endurance training programs used for developing peak cardiac performance and superb cardiorespiratory fitness (CRF). Studies consistently show that regular moderate-intensity physical activity (PA) is highly beneficial for long-term cardiovascular (CV) health.2, 3, 4 Improving the CRF from low to moderate to high will progressively improve CV prognosis and overall survival.5 However, the survival benefits from improvements in the CRF plateau at about 10 metabolic equivalents (with 1 metabolic equivalent equal to an oxygen consumption of 3.5 mL O2/kg body weight per minute), with no additional survival benefit accruing from higher CRF levels.5, 6, 7 Clearly, 30 minutes of regular vigorous PA enhances health and well-being, but performing 3-hour bouts of strenuous PA does not multiply the health benefits. Indeed, recent studies suggest that extreme exercise may evoke acute elevations in cardiac troponin I and B-type natriuretic peptide and evidence of transient myocardial dysfunction.8, 9

Cardiac overuse injury” is the term we have suggested for this increasingly common consequence of the “more exercise is better” strategy.4, 10 Many seasoned endurance athletes have experience with orthopedic overuse injuries such as plantar fasciitis, Achilles tendonitis, shin splints, and patellar chondromalacia. However, cardiac overuse injury may be associated with more ominous outcomes, including threatening cardiac arrhythmias, accelerated coronary plaque formation, premature aging of the heart, myocardial fibrosis, plaque rupture and acute coronary thrombosis, and even sudden cardiac death.11
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Mon Sep 01, 2014 8:58 am

Another issue with excess endurance exercise is atrial fibrillation. As we see again, inactivity is a risk factor, moderate exercise/activity decreases risk but excessive exercise increase risk.

In Health

This article, is a great overview of the literature.

http://www.everydayhealth.com/columns/j ... a-problem/

"The study (***See below) looked at the impact of levels of fitness at different ages in a large number of men. In this study, Drca and colleagues from the Karolinska University Hospital, in Stockholm, Sweden, collected information about physical activity from 44,410 Swedish men from the ages of 45-79 who did not have atrial fibrillation. Researchers followed the men for an average of 12 years. They separated the men into groups by their vigorous exercise level:

Less than 1 hour per week
1-2 hours per week
2-3 hours per week
4-5 hours per week
More than 5 hours per week

The authors found that if men developed a pattern of exercise of >5 hours per week, then their risk of atrial fibrillation was 19 percent higher than those who exercise <1 hour. It was a classic “U” shape curve with the lowest risk at 2-3 hours per week. The risk was highest in those that start >5 hours of vigorous exercise by the age of 30.

What they found next was, to me, the most important finding. In men who exercised >5 hours per week at age 30 and quit exercising later in life or regressed to <1 hour per week, the atrial fibrillation risk increased further to 49 percent. The increased risks remained even when accounting for all types of heart disease and heart disease risk factors; diabetes, high blood pressure, and being a smoker.

These authors made a second important observation. They found that leisure activity of walking or cycling did not increase risk, even if it was over 60 minutes a day. In fact, walking over 1 hour per day was associated with a 13 percent decrease in atrial fibrillation. This lower risk of atrial fibrillation was seen in almost all of the groups and was independent of what age the activity was started. In fact, becoming more active with low-moderate intensity exercise helped lower all traditional risk factors of heart disease as well as atrial fibrillation."

The research

***Atrial fibrillation is associated with different levels of physical activity levels at different ages in men
Heart doi:10.1136/heartjnl-2013-305304
Published Online First 14 May 2014

http://heart.bmj.com/content/early/2014 ... 4.abstract

Objective This study examines the influence of physical activity at different ages and of different types, on the risk of developing atrial fibrillation (AF) in a large cohort of Swedish men.

Methods Information about physical activity was obtained from 44 410 AF-free men, aged 45–79 years (mean age=60), who had completed a self-administered questionnaire at baseline in 1997. Participants reported retrospectively their time spent on leisure-time exercise and on walking or bicycling throughout their lifetime (at 15, 30 and 50 years of age, and at baseline (mean age=60)). Participants were followed-up in the Swedish National Inpatient Register for ascertainment of AF. Cox proportional hazards regression models were used to estimate relative risks (RR) with 95% CIs, adjusted for potential confounders.

Results During a median follow-up of 12 years, 4568 cases of AF were diagnosed. We observed a RR of 1.19 (95% CI 1.05 to 1.36) of developing AF in men who at the age of 30 years had exercised for >5 h/week compared with <1 h/week. The risk was even higher (RR 1.49, 95% CI 1.14 to 1.95) among the men who exercised >5 h/week at age 30 and quit exercising later in life (<1 h/week at baseline). Walking/bicycling at baseline was inversely associated with risk of AF (RR 0.87, 95% CI 0.77 to 0.97 for >1 h/day vs almost never) and the association was similar after excluding men with previous coronary heart disease or heart failure at baseline (corresponding RR 0.88, 95% CI 0.77 to 0.998).

Conclusions Leisure-time exercise at younger age is associated with an increased risk of AF, whereas walking/bicycling at older age is associated with a decreased risk.

Effect of Years of Endurance Exercise on Risk of Atrial Fibrillation and Atrial Flutter.
Am J Cardiol. 2014 Jul 30. pii: S0002-9149(14)01508-2. doi: 10.1016/j.amjcard.2014.07.047. [Epub ahead of print]


Emerging evidence suggests that endurance exercise increases the risk for atrial fibrillation (AF) in men, but few studies have investigated the dose-response relation between exercise and risk for atrial arrhythmias. Both exposure to exercise and reference points vary among studies, and previous studies have not differentiated between AF and atrial flutter. The aim of this study was to assess the risk for atrial arrhythmias by cumulative years of regular endurance exercise in men. To cover the range from physical inactivity to long-term endurance exercise, the study sample in this retrospective cohort study was based on 2 distinct cohorts: male participants in a long-distance cross-country ski race and men from the general population, in total 3,545 men aged ≥53 years. Arrhythmia diagnoses were validated by electrocardiograms during review of medical records. Regular endurance exercise was self-reported by questionnaire. A broad range of confounding factors was available for adjustment. The adjusted odds ratios per 10 years of regular endurance exercise were 1.16 (95% confidence interval 1.06 to 1.29) for AF and 1.42 (95% confidence interval 1.20 to 1.69) for atrial flutter. In stratified analyses, the associations were significant in cross-country skiers and in men from the general population. In conclusion, cumulative years of regular endurance exercise were associated with a gradually increased risk for AF and atrial flutter.

Increased risk of atrial fibrillation among elderly Norwegian men with a history of long-term endurance sport practice.
Scand J Med Sci Sports. 2013 Nov 21. doi: 10.1111/sms.12150. [Epub ahead of print]


Atrial fibrillation (AF) is the most common cardiac arrhythmia. The prevalence increases with increasing age. In middle-aged men, endurance sport practice is associated with increased risk of AF but there are few studies among elderly people. The aim of this study was to investigate the role of long-term endurance sport practice as a risk factor for AF in elderly men. A cross-sectional study compared 509 men aged 65-90 years who participated in a long-distance cross-country ski race with 1768 men aged 65-87 years from the general population. Long-term endurance sport practice was the main exposure. Self-reported AF and covariates were assessed by questionnaires. Risk differences (RDs) for AF were estimated by using a linear regression model. After multivariable adjustment, a history of endurance sport practice gave an added risk for AF of 6.0 percent points (pp) (95% confidence interval 0.8-11.1). Light and moderate leisure-time physical activity during the last 12 months reduced the risk with 3.7 and 4.3 pp, respectively, but the RDs were not statistically significant. This study suggests that elderly men with a history of long-term endurance sport practice have an increased risk of AF compared with elderly men in the general population.

Atrial fibrillation in endurance athletes.
Eur J Prev Cardiol. 2013 Jan 30;21(8):1040-1048. [Epub ahead of print]


There is a growing population of veteran endurance athletes, regularly participating in training and competition. Although the graded benefit of exercise on cardiovascular health and mortality is well established, recent studies have raised concern that prolonged and strenuous endurance exercise may predispose to atrial and ventricular arrhythmias. Atrial fibrillation (AF) and atrial flutter are facilitated by atrial remodelling, atrial ectopy, and an imbalance of the autonomic nervous system. Endurance sports practice has an impact on all of these factors and may therefore act as a promoter of these arrhythmias. In an animal model, long-term intensive exercise training induced fibrosis in both atria and increased susceptibility to AF. While the prevalence of AF is low in young competitive athletes, it increases substantially in the aging athlete, which is possibly associated with an accumulation of lifetime training hours and participation in competitions. A recent meta-analysis revealed a 5-fold increased risk of AF in middle-aged endurance athletes with a striking male predominance. Beside physical activity, height and absolute left atrial size are independent risk factors for lone AF and the stature of men per se may explain part of their higher risk of AF. Furthermore, for a comparable amount of training volume and performance, male non-elite athletes exhibit a higher blood pressure at rest and peak exercise, a more concentric type of left ventricular remodelling, and an altered diastolic function, possibly contributing to a more pronounced atrial remodelling. The sports cardiologist should be aware of the distinctive features of AF in athletes. Therapeutic recommendations should be given in close cooperation with an electrophysiologist. Reduction of training volume is often not desired and drug therapy not well tolerated. An early ablation strategy may be appropriate for some athletes with an impaired physical performance, especially when continuation of competitive activity is intended. This review focuses on the prevalence, risk factors, and mechanisms of AF in endurance athletes, and possible therapeutic options.

Endurance sport practice as a risk factor for atrial fibrillation and atrial flutter.
Europace. 2009 Jan;11(1):11-7. doi: 10.1093/europace/eun289. Epub 2008 Nov 6.


Although the benefits of regular exercise in controlling cardiovascular risk factors have been extensively proven, little is known about the long-term cardiovascular effects of regular and extreme endurance sport practice, such as jogging, cycling, rowing, swimming, etc. Recent data from a small series suggest a relationship between regular, long-term endurance sport practice and atrial fibrillation (AF) and flutter. Reported case control studies included less than 300 athletes, with mean age between 40 and 50. Most series recruited only male patients, or more than 70% males, who had been involved in intense training for many years. Endurance sport practice increases between 2 and 10 times the probability of suffering AF, after adjusting for other risk factors. The possible mechanisms explaining the association remain speculative. Atrial ectopic beats, inflammatory changes, and atrial size have been suggested. Some of the published studies found that atrial size was larger in athletes than in controls, and this was a predictor for AF. It has also been shown that the left atrium may be enlarged in as many as 20% of competitive athletes. Other proposed mechanisms are increased vagal tone and bradycardia, affecting the atrial refractory period; however, this may facilitate rather than cause the arrhythmia. In summary, recent data suggest an association between endurance sport practice and atrial fibrillation and flutter. The underlying mechanism explaining this association is unclear, although structural atrial changes (dilatation and fibrosis) are probably present. Larger longitudinal studies and mechanistic studies are needed to further characterize the association to clarify whether a threshold limit for the intensity and duration of physical activity may prevent AF, without limiting the cardiovascular benefits of exercise.
PMID: 18988654

Physical activity and incidence of atrial fibrillation in older adults: the cardiovascular health study.
Circulation. 2008 Aug 19;118(8):800-7. doi: 10.1161/CIRCULATIONAHA.108.785626. Epub 2008 Aug 4.



Vigorous exertion and endurance training have been reported to increase atrial fibrillation (AF). Associations of habitual light or moderate activity with AF incidence have not been evaluated.

We prospectively investigated associations of leisure-time activity, exercise intensity, and walking habits, assessed at baseline and updated during follow-up visits, with incident AF, diagnosed by annual 12-lead ECGs and hospital discharge records, from 1989 to 2001 among 5446 adults > or =65 years of age in the Cardiovascular Health Study. During 47 280 person-years of follow-up, 1061 new AF cases occurred (incidence 22.4/1000 person-years). In multivariable-adjusted analyses, leisure-time activity was associated with lower AF incidence in a graded manner, with 25% (hazard ratio [HR] 0.75, 95% confidence interval [CI] 0.61 to 0.90), 22% (HR 0.78, 95% CI 0.65 to 0.95), and 36% (HR 0.64, 95% CI 0.52 to 0.79) lower risk in quintiles 3, 4, and 5 versus quintile 1 (P for trend <0.001). Exercise intensity had a U-shaped relationship with AF (quadratic P=0.02): Versus no exercise, AF incidence was lower with moderate-intensity exercise (HR 0.72, 95% CI 0.58 to 0.89) but not with high-intensity exercise (HR 0.87, 95% CI 0.64 to 1.19). Walking distance and pace were each associated with lower AF risk in a graded manner (P for trend <0.001); when we assessed the combined effects of distance and pace, individuals in quartiles 2, 3, and 4 had 25% (HR 0.75, 95% CI 0.56 to 0.99), 32% (HR 0.68, 95% CI 0.50 to 0.92), and 44% (HR 0.56, 95% CI 0.38 to 0.82) lower AF incidence than individuals in quartile 1. Findings appeared unrelated to confounding by comorbidity or indication. After evaluation of cut points of moderate leisure-time activity (approximately 600 kcal/week), walking distance (12 blocks per week), and pace (2 mph), 26% of all new AF cases (95% CI 7% to 43%) appeared attributable to absence of these activities.

Light to moderate physical activities, particularly leisure-time activity and walking, are associated with significantly lower AF incidence in older adults.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Fri Oct 31, 2014 7:39 am


Do Moderate-Intensity and Vigorous-Intensity Physical Activities Reduce Mortality Rates to the Same Extent?
Shiroma EJ, Sesso HD, Moorthy MV, Buring JE, Lee IM.
J Am Heart Assoc. 2014 Oct 17;3(5). pii: e000802.

http://jaha.ahajournals.org/content/3/5 ... l.pdf+html


BACKGROUND: Limited data exist directly comparing the relative benefits of moderate- and vigorous-intensity activities with all-cause and cardiovascular (CV) disease mortality rates when controlling for physical activity volume.

METHODS AND RESULTS: We followed 7979 men (Harvard Alumni Health Study, 1988-2008) and 38 671 women (Women's Health Study, 1992-2012), assessing their physical activity and health habits through repeated questionnaires. Over a mean follow-up of 17.3 years in men and 16.4 years in women, there were 3551 deaths (1077 from CV disease) among men and 3170 deaths (620 from CV disease) among women. Those who met or exceeded an equivalent of the federal guidelines recommendation of at least 150 minutes of moderate-intensity activity, 75 minutes of vigorous-intensity activity, or a combination of the 2 that expended similar energy experienced significantly lower all-cause and CV disease-related mortality rates (men, 28% to 36% and 31% to 34%, respectively; women: 38% to 55% and 22% to 44%, respectively). When comparing different combinations of moderate- and vigorous-intensity activity and all-cause mortality rates, we observed sex-related differences. Holding constant the volume of moderate- to vigorous-intensity physical activity, men experienced a modest additional benefit when expending a greater proportion of moderate- to vigorous-intensity physical activity in vigorous-intensity activities (Ptrend=0.04), but women did not (Ptrend<0.001). Moderate- to vigorous-intensity physical activity composition was not associated with further cardiovascular mortality rate reductions in either men or women.

CONCLUSIONS: The present data support guidelines recommending 150 minutes of moderate-intensity activity per week, 75 minutes of vigorous-intensity activity per week, or an equivalent combination for mortality benefits. Among men, but not women, additional modest reductions in all-cause mortality rates are associated with a greater proportion of moderate- to vigorous-intensity physical activity performed at a vigorous intensity.


Physical Activity and Health: What Is the Best Dose?
Kaminsky LA, Montoye AH.
J Am Heart Assoc. 2014 Oct 17;3(5). pii: e001430.

Free Article
http://jaha.ahajournals.org/content/3/5 ... l.pdf+html


Clinicians and scientists have known for a long time of the many health benefits obtained by regularly performing physical activity (PA). Studies by Morris and colleagues1–2 50 to 60 years ago showed that male workers in occupations requiring them to be physically active had significantly lower rates of coronary heart disease in middle age than those with sedentary occupations. The research evidence base grew substantially over the years, leading to 2 major public health statements promoting the importance of PA for health and the American Heart Association adding physical inactivity to the major risk factor list in the 1990s.3–5 In 2008, the first federal Physical Activity Guidelines were issued based on evidence that engaging in 150 minutes per week of moderate-intensity PA or 75 minutes per week of vigorous-intensity PA would result in substantial health benefits.6 This recommendation implies that the total volume of PA, regardless of whether it is performed at moderate or vigorous intensity, is the key for stimulating health benefits. The study by Shiroma and colleagues7 in this issue of JAHA used an epidemiological approach to evaluate whether there were differences in mortality rates based on the proportion of total PA volume obtained with moderate or vigorous intensity. This experienced author group used data provided by 2 major cohorts, the Harvard Alumni Health Study and the Women's Health Study, each of which has brought us a wealth of evidence of factors associated with health, including PA. They report that the most active men and women had mortality rates 36% to 55% lower than those who were least active and that there was a modest (4% to 10%) additional benefit for men if a greater proportion of the total PA volume was of vigorous intensity.

The primary purpose of the study by Shiroma et al was to evaluate whether PA intensity had a differential effect on health benefits (mortality rates). This is important because, as they pointed out, our current understanding of the role of intensity is limited to a small number of epidemiological studies that have controlled for total PA volume. Their approach to investigating the role of intensity on health benefits, controlled for total volume, is a clear study strength; however, some challenges within their study design and data set should be considered to truly understand the role of PA intensity. These include the representativeness of the populations studied, the method of PA assessment, and the evaluation of health benefit only in terms of mortality.

There are always some considerations regarding the representativeness of the subjects for the general population in any epidemiological study. Participants in both the Harvard Alumni Health Study and the Women's Health Study were predominantly white, likely with an older average age, higher levels of education, and higher socioeconomic status than a general population. These factors may affect mortality rates or effects of PA on mortality. In this study, the representativeness of these cohorts' PA habits need to be considered in comparison to a US adult population. Because PA intensity was the key variable, it is important to consider the subjects' habits with regard to both total PA and amounts obtained at vigorous intensity. Total volume was determined by calculating metabolic equivalent (MET) hours per week (MET-h/week) to equate with the targets recommended in the Physical Activity Guidelines. This method uses the absolute intensity values of 3 and 6 METs as the thresholds for achieving moderate and vigorous intensity, respectively. The Physical Activity Guidelines explain that 150 minutes per week of moderate-intensity PA (using a value of 3.3 METs, the level associated with a brisk [3 miles per hour] walking pace) would equate to a volume of 500 MET minutes per week (or 8.3 [500/60 minutes] MET-h/week). Shiroma et al used 3 versus 3.3 METs for moderate intensity, and 7.5 MET-h/week was set as the lower limit for meeting the recommendations. Consequently, performing vigorous-intensity PA (6 METs) for 75 minutes per week would also be 7.5 MET-h/week. The men evaluated from the Harvard Alumni Health Study were reported to have a median value of 18.6 MET-h/week, which is 2.5 times the recommended PA volume in the Physical Activity Guidelines. The 75th percentile for these men was 37.4 MET-h/week, or ˜5 times the recommended volume. Indeed, almost three quarters of the men were meeting the recommendations of the Physical Activity Guidelines. The values for the women evaluated from the Women's Health Study also showed that a majority were meeting the Physical Activity Guidelines, as noted by a median value of 8.4 MET-h/week, with 25% of them averaging 20.5 MET-h/week, 2.7 times the recommended PA volume. Data from Hughes et al8 report that only 27% of adults aged =/>60 years met the recommendation of 150 minutes per week (34% of men, 22% of women) in the 1999–2004 survey period of the National Health and Nutrition Examination Survey (NHANES). It is clear that the subjects in the Harvard Alumni Health Study and the Women's Health Study were more active than the general US population, especially the men.

Another concern related to the PA profile of this subject group was noted in the groupings of the proportion of total PA performed at vigorous intensity. The authors acknowledged that the lack of additional mortality benefit in women could be attributed to the differences in the PA profiles of the men and the women, particularly because the subgroup of women with the highest percentage of vigorous-intensity PA to total PA actually had a distinctly lower volume (1.6 MET-h/week) than the other subgroups and was well below the recommendation in the Physical Activity Guidelines. The issue of the high total PA level and the pattern of accrual of vigorous-intensity PA may affect the generalizability of the findings. As the authors note, it may be that moderate and vigorous intensities have different health effects at lower levels of total PA. They make this observation because the women, with lower overall total PA levels, saw no additional benefit from vigorous-intensity PA, whereas the men (with higher total PA volume) did; however, the older age of men at the study start and the significantly higher mortality rates for men (3551 of 7979, 44.5%) than for women (1992 of 38 761, 5.1%) warrant caution when comparing the differences seen in the men and the women.

A major issue with any study of the influence of PA is how it is assessed. A recent scientific statement from the American Heart Association provided an extensive overview of PA assessment methodologies that included a summary table of strengths and weaknesses.9 The study by Shiroma et al used a recall questionnaire method, as is common in most epidemiological studies. The authors cite literature supporting moderate or high test–retest reliability and correlations with their questionnaire to activity recalls and diaries. In addition, previous studies they cited found moderately high correlations of the questionnaire to doubly labeled water, providing support that the questionnaire may provide acceptable measures of total PA. The authors, however, also acknowledged a recent study showing that self-reported assessments of PA do not compare favorably with accelerometer-assessed values for either moderate (r=0.23) or vigorous (r=0.36) intensities of PA.10 An additional limitation of the questionnaire used in the study by Shiroma et al is that it asked about 3 PA constructs, the first 2 of which we would consider less structured and more incidental activities: (1) city blocks of walking, (2) flights of stairs climbed, and (3) sports and recreational activities. The American Heart Association statement specifically notes that sporadic or incidental PA is recalled with low validity, potentially leading to high levels of misclassification of PA, especially with regard to specific intensity of PA.9 It is well understood that random misclassification of a variable often weakens associations of this variable with any outcomes (eg, mortality).11 Consequently, the lack of differences in the health benefits of moderate- and vigorous-intensity PA seen in the study by Shiroma et al may be due to misclassification of intensity by the questionnaire, which would bias results toward a null finding (ie, moderate- and vigorous-intensity PAs are no different in their health benefits).

Objective measures of PA, such as pedometers and accelerometers, are preferable for use over questionnaires when measurement validity is desired. Use of high-validity measurement instruments often results in stronger associations with health indices, for the reasons described. This concept was demonstrated in a recent study by Celis-Morales et al,12 who showed stronger, more consistent associations of accelerometry-measured PA and sedentary behavior with several health indices compared with use of a questionnaire. In addition, pedometers and especially accelerometers are well suited for capturing sporadic activities as well as planned PA, and their objectivity is a significant advantage compared with the recall bias commonly associated with questionnaires. Accelerometers have not typically been used in large studies because of their cost, limited capacity to capture data for long periods of time, and limited ability to accurately capture nonambulatory activities or activities of daily living (ie, cycling, household chores). Advances in accelerometer technology and methodology have improved their measurement accuracy in a variety of settings and allowed for use in large data-collection efforts such as NHANES. As accelerometer methodologies continue to be refined and improved, their use in epidemiological studies has the potential to vastly improve our knowledge of specific dimensions of PA (eg, intensity, duration, frequency) and associated health benefits. Combined use of self-report and accelerometry may yield even more useful data by being able to capitalize on each method's advantages and minimize their shortcomings.

Given some of the issues cited concerning the representativeness of the PA profile of the cohorts studied by Shiroma et al and the limitations in sensitivity of the methods to differentiate between moderate and vigorous activity, the reported modest additional benefit for men of vigorous-intensity activity may be questioned. The small additional benefit in only men led the authors to conclude “a focus on moderate-intensity PA is appropriate.” They based this conclusion on their mortality data and a 2011 meta-analysis that showed no difference in mortality rates between equal volumes (meeting Physical Activity Guideline recommendations) of moderate versus vigorous intensity. Other literature supports a potential additional value for vigorous-intensity PA. An excellent resource is a 2006 review paper that found lower risk of mortality and better improvements in cardiorespiratory fitness, diastolic blood pressure, and glucose control with vigorous- versus moderate-intensity PA when controlling for total energy expenditure (another common measure of PA volume).13 Interestingly, this review considered both epidemiological studies (mortality) and clinical exercise training studies (cardiovascular risk factors) and found greater benefit for vigorous-intensity exercise, at equivalent total PA volume, for both types of studies. Although the issue of controlling for total volume of PA is lacking in some clinical training studies comparing various exercise intensities, an abundant body of literature suggests that equal or superior health benefits are derived from vigorous-intensity PA.14 An area that seems to be gaining much interest, related to promising findings, is consideration of high-intensity interval training as an alternative approach to derive health benefits. A recent meta-analysis reported that this form of training, either as the sole form of training or in combination with continuous training programs, showed much larger-magnitude increases in cardiorespiratory fitness (maximum oxygen consumption increases of 0.5 to 1.0 L/min) than traditional exercise training programs in previously sedentary adults.15 Another recent high-intensity interval training study showed benefits in cardiorespiratory fitness, glucose control, blood pressure, blood lipids, and body fat.16 The most interesting aspect of this study was the benefit for cardiorespiratory fitness, glucose control, and blood pressure obtained in 10 weeks with as little as one 4-minute bout exercising at 90% of maximal heart rate for 3 days per week. For these subjects, the total weekly training volume was ˜2 MET-h/week. This relatively low total volume is a characteristic feature of most high-intensity interval-training protocols. High-intensity interval training has been shown to provide benefit in a wide variety of populations including many disease-based groups.17 Despite the lack of consistent findings of additional mortality benefits for the subjects in the study by Shiroma et al, it appears that performing vigorous-intensity PA can provide a number of health benefits.

The questions remain, what dose of PA will provide health benefits, and is there an additional benefit for those who choose to perform the activity at vigorous intensity? Shiroma et al provide strong support that achieving either the moderate- or vigorous-intensity targets recommended in the current Physical Activity Guidelines will delay mortality in older adults. The evidence-base supporting a wide variety of health benefits for this total volume of PA is conclusive. Studies seeking to tease out whether vigorous-intensity PA may provide additional or superior benefits are far from providing clear answers. In addition to taking individual health history, risk factors, current PA level, and interests into account, clinicians and allied health professionals should be strongly advocating that everyone strive to accumulate at least 500 MET minutes per week in PA of moderate to vigorous intensity.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Tue Feb 03, 2015 8:12 am

Dose of Jogging and Long-Term Mortality: The Copenhagen City Heart Study
J Am Coll Cardiol. February 10, 2015,65(5):411-419 doi:10.1016/j.jacc.2014.11.023

http://content.onlinejacc.org/mobile/ar ... ID=2108914

Background People who are physically active have at least a 30% lower risk of death during follow-up compared with those who are inactive. However, the ideal dose of exercise for improving longevity is uncertain.

Objectives The aim of this study was to investigate the association between jogging and long-term, all-cause mortality by focusing specifically on the effects of pace, quantity, and frequency of jogging.

Methods As part of the Copenhagen City Heart Study, 1,098 healthy joggers and 3,950 healthy nonjoggers have been prospectively followed up since 2001. Cox proportional hazards regression analysis was performed with age as the underlying time scale and delayed entry.

Results Compared with sedentary nonjoggers, 1 to 2.4 h of jogging per week was associated with the lowest mortality (multivariable hazard ratio [HR]: 0.29; 95% confidence interval [CI]: 0.11 to 0.80). The optimal frequency of jogging was 2 to 3 times per week (HR: 0.32; 95% CI: 0.15 to 0.69) or ≤1 time per week (HR: 0.29; 95% CI: 0.12 to 0.72). The optimal pace was slow (HR: 0.51; 95% CI: 0.24 to 1.10) or average (HR: 0.38; 95% CI: 0.22 to 0.66). The joggers were divided into light, moderate, and strenuous joggers. The lowest HR for mortality was found in light joggers (HR: 0.22; 95% CI: 0.10 to 0.47), followed by moderate joggers (HR: 0.66; 95% CI: 0.32 to 1.38) and strenuous joggers (HR: 1.97; 95% CI: 0.48 to 8.14).

Conclusions The findings suggest a U-shaped association between all-cause mortality and dose of jogging as calibrated by pace, quantity, and frequency of jogging. Light and moderate joggers have lower mortality than sedentary nonjoggers, whereas strenuous joggers have a mortality rate not statistically different from that of the sedentary group.

Optimal Dose of Running for Longevity: Is More Better or Worse?∗
J Am Coll Cardiol. February 10, 2015,65(5):420-422 doi:10.1016/j.jacc.2014.11.022

http://content.onlinejacc.org/mobile/ar ... id=2108913

Although it is well known that regular exercise and physical activity (PA) have health benefits, there is still an unanswered question: “Is it possible to have too much of a good thing?” In particular, is high-intensity PA, such as running, a healthful activity? The dose-response relationship between running and mortality is still subject to debate and controversy.

In this issue of the Journal, Schnohr et al. 1 report 3 major findings on jogging and all-cause mortality in 1,098 joggers and 3,950 nonjoggers from the Copenhagen City Heart Study. First, jogging even <1 h per week or 1 time per week is associated with significant mortality risk reduction compared with sedentary nonjoggers. Second, 1 to 2.4 h of jogging per week, with a frequency of 2 to 3 times per week, at a slow or average pace is most favorable as an optimal jogging time, frequency, and speed for reducing mortality. Third, higher jogging times (≥2.5 h per week), higher frequencies (>3 times per week), and faster paces are not associated with better survival compared with sedentary nonjoggers, suggesting a U-shaped association between jogging and mortality as well as loss of benefits with higher doses of jogging. Considering the current consensus of a linear dose-response relationship between total PA and health, indicating “the more the PA, the better for health and longevity,” these findings are intriguing. The good news is that the mortality benefits of light jogging will encourage more people to jog for health benefits as a “practical, achievable, and sustainable” goal, as the authors have stated.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Tue Feb 10, 2015 5:44 am

the recent study you posted from The Journal of the American College of Cardiology has received lots of criticism for a few of its methods, do you have a comment on that?

All studies have strengths & weaknesses. Even the China-Oxford project (The China Study), & those from Pritikin, Kempner, Ornish, etc etc.

It is never about any one article, good or bad as no one study ever decides anything. So, if you do not like the "strength" of the evidence in the last article on the topic that you are referring to, or the methods it used, then just remove it from the discussion as in and of itself, it does "disprove" anything, it just may not be strong in its "proof." Either way, You still have all of the above data, which is a fairly large & consistent growing body of evidence supporting my comments in this thread, which has been going on for years.

Remember, what matters most is the overall body of evidence, which is the point of this discussion and in my opinion, speaks for itself.

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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Sun Apr 19, 2015 9:43 am

Frequent physical activity may not reduce vascular disease risk as much as moderate activity: large prospective study of women in the United kingdom.
Armstrong ME, Green J, Reeves GK, Beral V, Cairns BJ; Million Women Study Collaborators.
Circulation. 2015 Feb 24;131(8):721-9. doi: 10.1161/CIRCULATIONAHA.114.010296. Epub 2015 Feb 16.
http://circ.ahajournals.org/content/131 ... l.pdf+html


BACKGROUND: Although physical activity has generally been associated with reduced risk of vascular disease, there is limited evidence about the effects of the frequency and duration of various activities on the incidence of particular types of vascular disease.

METHODS AND RESULTS: In 1998, on average, 1.1 million women without prior vascular disease reported their frequency of physical activity and many other personal characteristics. Three years later, they were asked about hours spent walking, cycling, gardening, and housework each week. Women were followed by record linkage to National Health Service cause-specific hospital admissions and death records. Cox regression was used to calculate adjusted relative risks for first vascular events in relation to physical activity. During an average of 9 years follow-up, 49,113 women had a first coronary heart disease event, 17,822 had a first cerebrovascular event, and 14,550 had a first venous thromboembolic event. In comparison with inactive women, those reporting moderate activity had significantly lower risks of all 3 conditions (P<0.001 for each). However, women reporting strenuous physical activity daily had higher risks of coronary heart disease (P=0.002), cerebrovascular disease (P<0.001), and venous thromboembolic events (P<0.001) than those reporting doing such activity 2 to 3 times per week. Risks did not differ between hemorrhagic and ischemic stroke, or between venous thromboembolic events with or without pulmonary embolism.

CONCLUSIONS: Moderate physical activity is associated with a lower risk of coronary heart disease, venous thromboembolic event, and cerebrovascular disease than inactivity. However, among active women, there is little to suggest progressive reductions in risk of vascular diseases with increasing frequency of activity.
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