Exercise, Health & You: How Much Is Enough?

A place to get your questions answered from McDougall staff dietitian, Jeff Novick, MS, RDN.

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

Postby JeffN » Wed Dec 28, 2016 9:43 am

Interesting bit of info from the CDC..

“Unintentional overexertion” is one of the top three causes of injuries that land adults in the emergency room

https://www.cdc.gov/injury/wisqars/pdf/ ... 2013-a.pdf

Be active but don't overdo it.

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

Postby JeffN » Wed Mar 29, 2017 8:36 am

Article

Kidney Injury and Repair Biomarkers in Marathon Runners
American Journal of Kidney Diseases
In Press
DOI: http://dx.doi.org/10.1053/j.ajkd.2017.01.045

http://www.ajkd.org/article/S0272-6386(17)30536-X/fulltext

Background
Investigation into strenuous activity and kidney function has gained interest given increasing marathon participation.

Study Design
Prospective observational study.

Setting & Participants
Runners participating in the 2015 Hartford Marathon.

Predictor
Completing a marathon.

Outcomes
Acute kidney injury (AKI) as defined by AKI Network (AKIN) criteria. Stage 1 AKI was defined as 1.5- to 2-fold or 0.3-mg/dL increase in serum creatinine level within 48 hours of day 0 and stage 2 was defined as a more than 2- to 3-fold increase in creatinine level. Microscopy score was defined by the number of granular casts and renal tubular epithelial cells.

Measurements
Samples were collected 24 hours premarathon (day 0), immediately postmarathon (day 1), and 24 hours postmarathon (day 2). Measurements of serum creatinine, creatine kinase, and urine albumin were completed, as well as urine microscopy analysis. 6 injury urine biomarkers (IL-6, IL-8, IL-18, kidney injury molecule 1, neutrophil gelatinase-associated lipocalin, and tumor necrosis factor α) and 2 repair urine biomarkers (YKL-40 and monocyte chemoattractant protein 1) were measured.

Results
22 marathon runners were included. Mean age was 44 years and 41% were men. 82% of runners developed an increase in creatinine level equivalent to AKIN-defined AKI stages 1 and 2. 73% had microscopy diagnoses of tubular injury. Serum creatinine, urine albumin, and injury and repair biomarker levels peaked on day 1 and were significantly elevated compared to day 0 and day 2. Serum creatine kinase levels continued to significantly increase from day 0 to day 2.

Limitations
Small sample size and limited clinical data available at all time points.

Conclusions
Marathon runners developed AKI and urine sediment diagnostic of tubular injury. An increase in injury and repair biomarker levels suggests structural damage to renal tubules occurring after marathon. The results of our study should be validated in larger cohorts with longer follow-up of kidney function.




Also

Med Page Today - Sports Medicine
Acute Kidney Damage Common in Marathon Runners
Runners should allow time between marathons
by F. Perry Wilson MD, MSCE
March 28, 2017

https://www.medpagetoday.com/SportsMedi ... cine/64191

A study appearing in the American Journal of Kidney Diseases included a startling statistic: 82% of marathon runners developed acute kidney injury during races. I sat down with the lead and senior authors of the study to discuss the implications, including ways that dedicated marathon runners can avoid kidney damage while maintaining pace.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Sat Apr 08, 2017 9:31 am

For those who follow this thread, here are a few links to some research that has been going on over the last few years (and decades) on activity/exercise. It has to do with how much exercise is enough and are much higher levels of exercise/activity the reason why ancestral and hunter-gatherers had an easier time avoiding excess weight and obesity. It also looks at the role our modern sedentary lifestyle plays in the weight equation reinforcing several points in this thread. I am working on a graphic representation of what all this is saying.

In Health
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SCIENTIFIC AMERICAN
FEBRUARY 2017
The Exercise Paradox
https://www.scientificamerican.com/arti ... e-paradox/

Studies of how the human engine burns calories help to explain why physical activity does little to control weight—and how our species acquired some of its most distinctive traits

(Unfortunately, this one is behind a pay wall. Here is a link to a recording of it and a PDF of it that is available for a short time)

https://us.ivoox.com/en/the-exercise-pa ... 909_1.html

http://dropcanvas.com/1fcrc



Why do individuals not lose more weight from an exercise intervention at a defined dose? An energy balance analysis.
Obes Rev. 2012 Oct;13(10):835-47.
doi: 10.1111/j.1467-789X.2012.01012.x. Epub 2012 Jun 11.
https://www.ncbi.nlm.nih.gov/pubmed/22681398

Abstract
Weight loss resulting from an exercise intervention tends to be lower than predicted. Modest weight loss can arise from an increase in energy intake, physiological reductions in resting energy expenditure, an increase in lean tissue or a decrease in non-exercise activity. Lower than expected, weight loss could also arise from weak and invalidated assumptions within predictive models. To investigate these causes, we systematically reviewed studies that monitored compliance to exercise prescriptions and measured exercise-induced change in body composition. Changed body energy stores were calculated to determine the deficit between total daily energy intake and energy expenditures. This information combined with available measurements was used to critically evaluate explanations for low exercise-induced weight loss. We conclude that the small magnitude of weight loss observed from the majority of evaluated exercise interventions is primarily due to low doses of prescribed exercise energy expenditures compounded by a concomitant increase in caloric intake.


Hunter-Gatherer Energetics and Human Obesity
Published: July 25, 2012
PLoS ONE 7(7): e40503.
http://dx.doi.org/10.1371/journal.pone.0040503
http://journals.plos.org/plosone/articl ... ne.0040503

Abstract

Western lifestyles differ markedly from those of our hunter-gatherer ancestors, and these differences in diet and activity level are often implicated in the global obesity pandemic. However, few physiological data for hunter-gatherer populations are available to test these models of obesity. In this study, we used the doubly-labeled water method to measure total daily energy expenditure (kCal/day) in Hadza hunter-gatherers to test whether foragers expend more energy each day than their Western counterparts. As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners. Nonetheless, average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size. The metabolic cost of walking (kcal kg−1 m−1) and resting (kcal kg−1 s−1) were also similar among Hadza and Western groups. The similarity in metabolic rates across a broad range of cultures challenges current models of obesity suggesting that Western lifestyles lead to decreased energy expenditure. We hypothesize that human daily energy expenditure may be an evolved physiological trait largely independent of cultural differences


Relation between Caloric Intake, Body Weight, and Physical Work
STUDIES IN AN INDUSTRIAL MALE POPULATION IN WEST BENGAL
Am J Clin Nutr
March 1956
vol. 4 no. 2 169-175

http://ajcn.nutrition.org/content/4/2/169.abstract

The relation between caloric intake, body weight, and physical work was established in a group of 213 mill workers in West Bengal. These workers covered a wide range of physical activity, from sedentary to very hard work. It was found that caloric intake increases with activity only within a certain zone ("normal activity"). Below that range ("sedentary zone") a decrease in activity is not followed by a decrease in food intake but, on the contrary, by an increase. Body weight is also increased in that zone. The picture is similar to that previously found in experimental animals.



Popular Press Articles

Why Physical Activity Does Little to Control Weight
SkepDoc's Corner
February 16, 2017
http://www.csicop.org/specialarticles/s ... rol_weight


Debunking the Hunter-Gatherer Workout
NY TImes
August 24, 2012
https://mobile.nytimes.com/2012/08/26/o ... rkout.html


Dieting vs. Exercise for Weight Loss
NY Times
August 1, 2012
https://mobile.nytimes.com/blogs/well/2 ... /?referer=
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Mon May 08, 2017 12:50 pm

Only an abstract presented at a conference so we will wait to see the fully peer reviewed and published study

Roca E, Nescolarde L, Lupon J, Barallat J, et al. Cardiac biomarkers dynamics in amateur marathon runners. European Society of Cardiology Heart Failure 2017; April 30, 2017; Paris, France. Abstract 822

Background: Strenuous exercise such a marathon race might induce an increase of the blood concentrations of some cardiac biomarkers usually measured for diagnosis and prognosis prediction of heart diseases. However the behavior of different cardiac biomarkers around a marathon race in people of both genders has not been well elucidated.

Objective: 1) To assess baseline, just after the marathon race and 2 days after the race blood concentrations of NTproBNP, hs-TnT and ST2; 2) Try to find some relationship between the observed changes and demographic and performance characteristics.

Subjects and methods: 79 subjects (72.2% men), with a mean age of 39 ± 6.2 years (70.9% = 35 years) were studied. Three blood samples were obtained: 24-48 h before the race, in the immediate hours after the race and 48h hours after the race.

Results: Baseline data: hs-TnT blood levels tended to be higher in women (p=0.07). Only NTproBNP correlated with age (p=0.007). hs-TnT (p=0.01) correlated with weekly training hours and inversely correlated with the real time for completing the race (p=0.009). No biomarker correlated with the years of training. Biomarkers’ dynamics: Blood levels of the three cardiac biomarkers significantly increased during the race (Table, p<0.001 for all). NTproBNP and ST2 decreased to similar pre-race values 48h hours after the race, while hs-TnT blood levels decreased but their remained higher than those pre-race (Table, p<0.001). Relationship with biomarker dynamics: We found higher increase of hs-TnT in women (p=0.03). We did not found any significant relationship between increase in the studied biomarkers and age or years of training. We found inverse relationship between weekly training hours and ST2 increase (p=0.007), and direct relationship between race time and hs-TnT (p<0.001) and ST2 (p=0.052) increase. In multivariable lineal regression analyses including age, sex and those variables with a p-value =0.10 in the correlation analyses, race time remained independently associated with ST2 (p=0.031) and hs-TnT (p<0.001) increase.

Conclusions: cardiac biomarkers significantly increased during a marathon race in amateur runners. Such increase reached abnormal values for hs-TnT and ST2, and was significantly associated with worse athlete performance.


Public Article

Medscape Coverage from the
European Society of Cardiology Heart Failure (ESC-HF) 2017

Cardiac Biomarkers Jump After Marathons in Recreational Runners
Steve Stiles
May 01, 2017

http://www.medscape.com/viewarticle/879343
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Sun Jun 18, 2017 12:56 pm

Troponin T is released into the blood stream when damage to the heart muscle occurs

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A randomized cross-over study of the acute effects of running 5 km on glucose, insulin, metabolic rate, cortisol and Troponin T.
Keselman B, Vergara M, Nyberg S, Nystrom FH.
PLoS One. 2017 Jun 16;12(6):e0179401. doi: 10.1371/journal.pone.0179401. eCollection 2017.
PMID: 28622349

Abstract

BACKGROUND:
We aimed to study the impact by running 5 km, at maximal speed, on the normal variations of metabolic variables related to glucose, insulin, insulin sensitivity, cortisol, glucagon, Troponin T and metabolic rate.

MATERIAL AND METHODS:
Five women and 12 men 25.7±5.2 years of age with a body-mass-index of 22.5±2.3 kg/m2 where recruited to run 5 km at individual maximal speed in the morning, and to a corresponding day of rest, followed by standardized breakfast and lunch meals. Blood sampling and measurement of indirect calorimetry were done before and after meals. The participants were randomized regarding the order of the two trial-days in this cross-over study.

RESULTS:
Insulin and cortisol levels were higher, and insulin sensitivity was lower, on the race-day compared with the day of rest (linear mixed model: p<0.0001 for all three analyses). However, glucose levels and metabolic rate did not differ between the two trial days (p = 0.29 and p = 0.53, respectively). When analyzing specific time-points we found that glucose increased from 5.01±0.37 mmol/l to 6.36 ± 1.3 mmol/l, p<0.0001, by running, while serum insulin concomitantly increased from 42±21 to 90±54 pmol/l, p<0.0001. In accordance, the QUICKI index of serum sensitivity, 1/(log10insulin+log10glucose), was lowered post-race, p<0.0001. Serum cortisol levels increased from 408±137 nmol/l to 644±171 nmol/l, p<0.0001, post-race while serum glucagon levels were unaffected. Troponin T was detectable in serum post-race in 12 out of the 17 participants and reached or surpassed the clinical reference level of 15 ng/l in three subjects. Post-race electrocardiograms displayed no pathologies.

CONCLUSIONS:
Relatively short running-races can apparently induce a reduction in insulin sensitivity that is not fully compensated by concomitantly increased insulin secretion intended to ensure euglycemia. Since also Troponin T was detected in plasma in a majority of the participants, our data suggest that it is possible to induce considerable metabolic stress by running merely 5 km, when striving for maximal speed.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Sun Jul 23, 2017 8:08 pm

Two more new ones


1) Relationship Between Lifelong Exercise Volume and Coronary Atherosclerosis in Athletes
Circulation. 2017;136:138-148
Originally published April 27, 2017

https://doi.org/10.1161/CIRCULATIONAHA.117.027834

Abstract

Background: Higher levels of physical activity are associated with a lower risk of cardiovascular events. Nevertheless, there is debate on the dose-response relationship of exercise and cardiovascular disease outcomes and whether high volumes of exercise may accelerate coronary atherosclerosis. We aimed to determine the relationship between lifelong exercise volumes and coronary atherosclerosis.

Methods: Middle-aged men engaged in competitive or recreational leisure sports underwent a noncontrast and contrast-enhanced computed tomography scan to assess coronary artery calcification (CAC) and plaque characteristics. Participants reported lifelong exercise history patterns. Exercise volumes were multiplied by metabolic equivalent of task (MET) scores to calculate MET-minutes per week. Participants’ activity was categorized as <1000, 1000 to 2000, or >2000 MET-min/wk.

Results: A total of 284 men (age, 55±7 years) were included. CAC was present in 150 of 284 participants (53%) with a median CAC score of 35.8 (interquartile range, 9.3–145.8). Athletes with a lifelong exercise volume >2000 MET-min/wk (n=75) had a significantly higher CAC score (9.4 [interquartile range, 0–60.9] versus 0 [interquartile range, 0–43.5]; P=0.02) and prevalence of CAC (68%; adjusted odds ratio [ORadjusted]=3.2; 95% confidence interval [CI], 1.6–6.6) and plaque (77%; ORadjusted=3.3; 95% CI, 1.6–7.1) compared with <1000 MET-min/wk (n=88; 43% and 56%, respectively). Very vigorous intensity exercise (≥9 MET) was associated with CAC (ORadjusted=1.47; 95% CI, 1.14–1.91) and plaque (ORadjusted=1.56; 95% CI, 1.17–2.08). Among participants with CAC>0, there was no difference in CAC score (P=0.20), area (P=0.21), density (P=0.25), and regions of interest (P=0.20) across exercise volume groups. Among participants with plaque, the most active group (>2000 MET-min/wk) had a lower prevalence of mixed plaques (48% versus 69%; ORadjusted=0.35; 95% CI, 0.15–0.85) and more often had only calcified plaques (38% versus 16%; ORadjusted=3.57; 95% CI, 1.28–9.97) compared with the least active group (<1000 MET-min/wk).

Conclusions: Participants in the >2000 MET-min/wk group had a higher prevalence of CAC and atherosclerotic plaques. The most active group, however, had a more benign composition of plaques, with fewer mixed plaques and more often only calcified plaques. These observations may explain the increased longevity typical of endurance athletes despite the presence of more coronary atherosclerotic plaque in the most active participants.



2) Prevalence of Subclinical Coronary Artery Disease in Masters Endurance Athletes with a Low Atherosclerotic Risk Profile

Circulation. 2017;CIRCULATIONAHA.116.026964
Originally published May 2, 2017

https://doi.org/10.1161/CIRCULATIONAHA.116.026964

Abstract

Background—Studies in middle aged and older (masters) athletes with atherosclerotic risk factors for coronary artery disease (CAD) report higher coronary artery calcium (CAC) scores compared with sedentary individuals. Few studies have assessed the prevalence of CAD in masters athletes with a low atherosclerotic risk profile.

Methods—We assessed 152 masters athletes aged 54.4±8.5 years (70% male) and 92 controls of similar age, sex and low Framingham 10 year CAD risk scores with an echocardiogram, exercise stress test, CT coronary angiogram, and cardiovascular magnetic resonance imaging (CMRI) with late gadolinium enhancement (LGE) and a 24-hour Holter. Athletes had participated in endurance exercise for an average of 31±12.6 years. The majority (77%) were runners with a median of 13 marathon runs per athlete.

Results—Most athletes (60%) and controls (63%) had a normal CAC score. Male athletes had a higher prevalence of atherosclerotic plaques of any luminal irregularity (44.3% vs 22.2%;p=0.009) compared with sedentary males and only male athletes showed a CAC ≥300 Agatson units (AU)(11.3%), and a luminal stenosis ≥50% (7.5%). Male athletes demonstrated predominantly calcific plaques (72.7%) whereas sedentary males showed predominantly mixed morphology plaques (61.5%). The number of years of training was the only independent variable associated with increased risk of CAC >70th percentile for age and/or luminal stenosis ≥50% in male athletes: OR 1.08 (95% CI 1.01-1.15);p=0.016. 15 (14%) male athletes but none of the controls revealed LGE on CMRI. Of these, 7 had a pattern consistent with previous myocardial infarction including 3(42%) with a luminal stenosis ≥ 50% in the corresponding artery.

Conclusions—Most lifelong masters endurance athletes with a low atherosclerotic risk profile have normal CAC scores. Male athletes are more likely to have a CAC score >300 AU or coronary plaques compared with sedentary males with a similar risk profile. The significance of these observations is uncertain but the predominantly calcific morphology of the plaques in athletes indicates potentially different pathophysiological mechanisms for plaque formation in athletic versus sedentary men. Whereas coronary plaques are more abundant in athletes, their stable nature could mitigate the risk of plaque rupture and acute myocardial infarction.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Tue Sep 19, 2017 1:53 pm

BMJ article

Men over 40 are most at risk of sudden death during triathlons
BMJ 2017; 358
doi: https://doi.org/10.1136/bmj.j4326
Published 19 September 2017
http://www.bmj.com/content/358/bmj.j4326


Original Paper

Death and Cardiac Arrest in U.S. Triathlon Participants, 1985 to 2016: A Case Series.
Ann Intern Med.
[Epub ahead of print 19 September 2017]
doi: 10.7326/M17-0847
http://annals.org/aim/article/2654457/d ... -2016-case

Abstract
Background:

Reports of race-related triathlon fatalities have raised questions regarding athlete safety.

Objective:
To describe death and cardiac arrest among triathlon participants.

Participants:
Participants in U.S. triathlon races from 1985 to 2016.

Measurements:
Data on deaths and cardiac arrests were assembled from such sources as the U.S. National Registry of Sudden Death in Athletes (which uses news media, Internet searches, LexisNexis archival databases, and news clipping services) and USA Triathlon (USAT) records. Incidence of death or cardiac arrest in USAT-sanctioned races from 2006 to 2016 was calculated.

Results:
A total of 135 sudden deaths, resuscitated cardiac arrests, and trauma-related deaths were compiled; mean age of victims was 46.7 ± 12.4 years, and 85% were male. Most sudden deaths and cardiac arrests occurred in the swim segment (n = 90); the others occurred during bicycling (n = 7), running (n = 15), and postrace recovery (n = 8). Fifteen trauma-related deaths occurred during the bike segment. Incidence of death or cardiac arrest among USAT participants (n = 4 776 443) was 1.74 per 100 000 (2.40 in men and 0.74 in women per 100 000; P < 0.001). In men, risk increased substantially with age and was much greater for those aged 60 years and older (18.6 per 100 000 participants). Death or cardiac arrest risk was similar for short, intermediate, and long races (1.61 vs. 1.41 vs. 1.92 per 100 000 participants). At autopsy, 27 of 61 decedents (44%) had clinically relevant cardiovascular abnormalities, most frequently atherosclerotic coronary disease or cardiomyopathy.

Limitations:
Case identification may be incomplete and may underestimate events, particularly in the early study period. In addition, prerace medical history is unknown in most cases.

Conclusion:
Deaths and cardiac arrests during the triathlon are not rare; most have occurred in middle-aged and older men. Most sudden deaths in triathletes happened during the swim segment, and clinically silent cardiovascular disease was present in an unexpected proportion of decedents.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Mon Sep 25, 2017 5:16 am

Physical activity and 22-year all-cause and coronary heart disease mortality.
Krause N, et al. Am J Ind Med. 2017.

https://www.ncbi.nlm.nih.gov/m/pubmed/2 ... 2028940659
Abstract

BACKGROUND: This study explores the effects of occupational (OPA) and leisure time physical activity (LTPA) on mortality relative to cardiorespiratory fitness and pre-existing coronary heart disease (CHD).

METHODS: Associations between OPA, measured as energy expenditure (kcal/day) and relative aerobic workload (%VO2 max), LTPA, and 22-year mortality among 1891 Finnish men were assessed by Cox regression models stratified by CHD and adjusted for 19 confounders.

RESULTS: In fully adjusted models, each 10% of relative aerobic workload increased all-cause mortality by 13% and CHD mortality 28% (P < 0.01). Compared to healthy subjects, men with CHD experienced lower mortality risks due to OPA and higher risks due to LTPA. While LTPA had no effect among healthy men, in men with CHD each weekly hour of conditioning LTPA increased all-cause mortality risks by 10% and CHD mortality by14%.

CONCLUSION: OPA was positively associated with both all-cause and CHD mortality. LTPA was not protective. Among men with CHD, LTPA increased mortality risks.
PMID 28940659
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Tue Oct 17, 2017 2:24 pm

Article

Physically active white men at high risk for plaque buildup in arteries
Science Daily
October 16, 2017

https://www.sciencedaily.com/releases/2 ... 144846.htm

Summary:
White men who exercise at high levels are 86 percent more likely than people who exercise at low levels to experience a buildup of plaque in the heart arteries by middle age, a new study suggests.


Study

25-Year Physical Activity Trajectories and Development of Subclinical Coronary Artery Disease as Measured by Coronary Artery Calcium: The Coronary Artery Risk Development in Young Adults (CARDIA) Study
Mayo Clinic Proceedings
Published Oct 16, 2017
DOI: http://dx.doi.org/10.1016/j.mayocp.2017.07.016

Abstract

Objective
To evaluate 25-year physical activity (PA) trajectories from young to middle age and assess associations with the prevalence of coronary artery calcification (CAC).

Patients and Methods
This study includes 3175 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study who self-reported PA by questionnaire at 8 follow-up examinations over 25 years (from March 1985-June 1986 through June 2010-May 2011). The presence of CAC (CAC>0) at year 25 was measured using computed tomography. Group-based trajectory modeling was used to identify PA trajectories with increasing age.

Results
We identified 3 distinct PA trajectories: trajectory 1, below PA guidelines (n=1813; 57.1%); trajectory 2, meeting PA guidelines (n=1094; 34.5%); and trajectory 3, 3 times PA guidelines (n=268; 8.4%). Trajectory 3 participants had higher adjusted odds of CAC>0 (adjusted odds ratio [OR], 1.27; 95% CI, 0.95-1.70) vs those in trajectory 1. Stratification by race showed that white participants who engaged in PA 3 times the guidelines had higher odds of developing CAC>0 (OR, 1.80; 95% CI, 1.21-2.67). Further stratification by sex showed higher odds for white males (OR, 1.86; 95% CI, 1.16-2.98), and similar but nonsignificant trends were noted for white females (OR, 1.71; 95% CI, 0.79-3.71). However, no such higher odds of CAC>0 for trajectory 3 were observed for black participants.

Conclusion
White individuals who participated in 3 times the recommended PA guidelines over 25 years had higher odds of developing coronary subclinical atherosclerosis by middle age. These findings warrant further exploration, especially by race, into possible biological mechanisms for CAC risk at very high levels of PA.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Fri Nov 17, 2017 8:34 am

Being sedentary is really bad but it doesn’t take a lot of physical activity to get a huge benefit

"Interestingly, we found that light intensity PA was an even stronger predictor of mortality than MVPA. This is an important contribution to the literature since the majority of prior research has focused on the health effects of MVPA, while the impact of light intensity PA is less explored."


Accelerometer-measured sedentary time and physical activity-A 15 year follow-up of mortality in a Swedish population-based cohort.
Dohrn IM, Sjöström M, Kwak L, Oja P, Hagströmer M.
J Sci Med Sport. 2017 Nov 7. pii: S1440-2440(17)31748-6. doi: 10.1016/j.jsams.2017.10.035. [Epub ahead of print]
PMID: 29128418
http://www.jsams.org/article/S1440-2440(17)31748-6/fulltext
http://www.jsams.org/article/S1440-2440(17)31748-6/pdf

Abstract

OBJECTIVES:
To investigate the associations of objectively assessed sedentary time, light intensity physical activity (PA), moderate to vigorous intensity PA (MVPA), and total PA with all-cause mortality and mortality from cardiovascular disease (CVD) or cancer in a Swedish population-based cohort with 15 years follow-up time.
DESIGN:
Longitudinal prospective cohort study.

METHODS:
Data from 851 persons (56% women) ≥35 years at baseline were included. Primary exposure variables were time (min/day) spent sedentary, in light intensity PA and in MVPA, and total counts from an Actigraph 7164 accelerometer. Data on all-cause mortality and mortality from CVD or cancer were obtained from Swedish registers. Cox proportional hazards models estimated hazard ratios (HR) of mortality with 95% confidence intervals (CI).

RESULTS:
Compared with the least sedentary participants, those in the most sedentary tertile had an increased risk of all-cause mortality, HR: 2.7 (1.4, 5.3), CVD mortality, HR: 5.5 (1.4, 21.2) and cancer mortality, HR: 4.3 (1.2, 16.0). For all-cause mortality, those in the highest light intensity PA tertile had a HR 0.34 (0.17, 0.67) compared with the lowest tertile. A similar pattern was found for CVD and cancer mortality. More time spent in MVPA was associated with the largest risk reduction for CVD mortality, with an almost 90% lower risk in the tertile with the most time in MVPA.

CONCLUSIONS:
This study confirms a strong inverse relationship between MVPA and mortality, and adds new insight for the understanding of the associations between sedentary time and light intensity PA and mortality.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Wed Nov 22, 2017 12:38 pm

Again, Being sedentary is really bad but it doesn’t take a lot of physical activity to get a huge benefit


Impact of physical activity on the risk of cardiovascular disease in middle-aged and older adults: EPIC Norfolk prospective population study
European Journal of Preventive Cardiology
November 21, 2017

There is broad consensus that regular physical activity yields major health benefits. However, current guidelines on physical activity are mainly aimed at middle-aged adults. It is unclear whether physical activity also translates into cardiovascular health benefits in older adults. Therefore, we aimed to compare the association between different levels of physical activity and the risk of cardiovascular disease (CVD) in elderly to middle-aged individuals.

We analysed data from the EPIC Norfolk prospective population study. Cox proportional hazards models were used to analyse the association between physical activity levels and time to CVD events in three age categories (<55, 55–65 and >65 years). Interaction between age categories and physical activity levels was assessed.

Analyses were based on 24,502 study participants aged 39–79 years. A total of 5240 CVD events occurred during 412,954 person-years follow-up (median follow-up was 18.0 years). Among individuals aged over 65 years, hazard ratios for CVD were 0.86 (95% confidence interval (CI) 0.78–0.96), 0.87 (95% CI 0.77–0.99) and 0.88 (95% CI 0.77–1.02) in moderately inactive, moderately active and active people, respectively, compared to inactive people. Among people aged 55–65 and less than 55 years, the associations were directionally similar, but not statistically significant. The interaction term between physical activity levels and age categories was not significant (P = 0.38).

The inverse association between physical activity and the risk of CVD was significant in elderly and comparable with middle-aged individuals. In addition, we observed that modest levels of physical activity confer benefits in terms of CVD risk, compared to being completely inactive.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Thu Jan 11, 2018 8:54 am

Proper Exercise Can Reverse Damage From Heart Aging
Released: 4-Jan-2018 12:45 PM EST
Source Newsroom: UT Southwestern Medical Center
https://www.newswise.com/articles/proper-exercise-can-reverse-damage-from-heart-aging

Newswise — DALLAS – Jan. 8, 2018 – Exercise can reverse damage to sedentary, aging hearts and help prevent risk of future heart failure – if it’s enough exercise, and if it’s begun in time, according to a new study by cardiologists at UT Southwestern and Texas Health Resources.

The regimen included exercising four to five times a week, generally in 30-minute sessions, plus warmup and cool-down:
- One of the weekly sessions included a high-intensity 30-minute workout, such as aerobic interval sessions in which heart rate tops 95 percent of peak rate for 4 minutes, with 3 minutes of recovery, repeated four times (a so-called “4 x 4”).
- Each interval session was followed by a recovery session performed at relatively low intensity.
- One day’s session lasted an hour and was of moderate intensity. (As a “prescription for life,” Levine said this longer session could be a fun activity such as tennis, aerobic dancing, walking, or biking.)
- One or two other sessions were performed each week at a moderate intensity, meaning the participant would break a sweat, be a little short of breath, but still be able to carry on a conversation -- the “talk test.” In the study, exercise sessions were individually prescribed based on exercise tests and heart rate monitoring.
- One or two weekly strength training sessions using weights or exercise machines were included on a separate day, or after an endurance session.


Study

Reversing the Cardiac Effects of Sedentary Aging in Middle Age—A Randomized Controlled Trial
Implications For Heart Failure Prevention
Circulation. 2018;137:00–00.
DOI: 10.1161/CIRCULATIONAHA.117.030617

BACKGROUND: Poor tness in middle age is a risk factor for heart failure, particularly heart failure with a preserved ejection fraction. The development of heart failure with a preserved ejection fraction is likely mediated through increased left ventricular (LV) stiffness, a consequence of sedentary aging. In a prospective, parallel group, randomized controlled trial, we examined the effect of 2 years of supervised high- intensity exercise training on LV stiffness.

METHODS: Sixty-one (48% male) healthy, sedentary, middle-aged participants (53±5 years) were randomly assigned to either 2 years of exercise training (n=34) or attention control (control; n=27). Right heart catheterization and 3-dimensional echocardiography were performed with preload manipulations to de ne LV end-diastolic pressure-volume relationships and Frank-Starling curves. LV stiffness was calculated by curve t of the diastolic pressure-volume curve. Maximal oxygen uptake. (Vo2max) was measured to quantify changes in tness.

RESULTS: Fifty-three participants completed the study. Adherence to prescribed exercise sessions was 88±11%. Vo2max increased by 18% (exercise training: pre 29.0±4.8 to post 34.4±6.4; control: pre 29.5±5.3 to post 28.7±5.4, group×time P<0.001) and LV stiffness was reduced (right/downward shift in the end-diastolic pressure-volume relationships; preexercise training stiffness constant 0.072±0.037 to postexercise training 0.051±0.0268, P=0.0018), whereas there was no change in controls (group×time P<0.001; pre stiffness constant 0.0635±0.026 to post 0.062±0.031, P=0.83). Exercise increased LV end-diastolic volume (group×time P<0.001), whereas pulmonary capillary wedge pressure was unchanged, providing greater stroke volume for any given lling pressure (loading×group×time P=0.007).

CONCLUSIONS: In previously sedentary healthy middle-aged adults, 2 years of exercise training improved maximal oxygen uptake and decreased cardiac stiffness. Regular exercise training may provide protection against the future risk of heart failure with a preserved ejection fraction by preventing the increase in cardiac stiffness attributable to sedentary aging.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Fri Feb 09, 2018 12:22 pm

One more for the benefit of even light physical activity. The biggest bang for the buck comes from moving from being sedentary to doing light to moderate physical activity. Beyond that, there is diminishing returns and increasing risks

Jeff

Replacing sedentary time with physical activity: a 15-year follow-up of mortality in a national cohort.
Dohrn IM, Kwak L, Oja P, Sjöström M, Hagströmer M.
Clin Epidemiol. 2018 Jan 25;10:179-186. doi: 10.2147/CLEP.S151613. eCollection 2018.
PMID: 29416378
https://www.dovepress.com/replacing-sed ... ticle-CLEP

Abstract
BACKGROUND:
Sedentary behavior is associated with health risks in adults. The potential benefits of reducing sedentary time may be dependent not only on decrease per se, but also on the type of activity it replaces. Few longitudinal studies have investigated the effects on mortality when replacing objectively assessed sedentary time with another physical activity (PA) behavior.

OBJECTIVE:
To investigate the effects of replacing objectively assessed sedentary time with time in light-intensity PA or moderate-vigorous PA (MVPA) on all-cause mortality, cardiovascular disease (CVD) mortality or cancer mortality in a cohort with 15 years follow-up time.

METHODS:
In total, 851 women and men from the population-based Sweden Attitude Behaviour and Change study were included. Time spent sedentary, in light-intensity PA and in MVPA were assessed using an Actigraph 7164 accelerometer. Mortality data were obtained from Swedish registers. Cox proportional hazards models estimated hazard ratios (HR) of mortality with 95% confidence intervals (CI) and isotemporal substitution models were used to estimate the effect of replacing sedentary behavior with PA for the same amount of time.

RESULTS:
Over a follow-up of 14.2 years (SD 1.9) with 12,117 person-years at risk, 79 deaths occurred, 24 deaths from CVD, 27 from cancer, and 28 from other causes. Replacing 30 minutes/day of sedentary time with light-intensity PA was associated with significant reduction in all-cause mortality risk (HR: 0.89, 95% CI: 0.81-0.98) and CVD mortality risk (HR: 0.76, 95% CI: 0.63-0.92). Replacing 10 minutes of sedentary time with MVPA was associated with reduction in CVD mortality risk (HR: 0.62, 95% CI: 0.42-0.91). No statistically significant reductions were found for cancer mortality.

CONCLUSION:
This statistical modelling study suggests that replacing sedentary time with light-intensity PA could have beneficial effect on both all-cause mortality and CVD mortality. Replacing sedentary time with MVPA could reduce CVD mortality.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Fri Apr 27, 2018 2:12 pm

How does light-intensity physical activity associate with adult cardiometabolic health and mortality? Systematic review with meta-analysis of experimental and observational studies.
Br J Sports Med. 2018 Apr 25. pii: bjsports-2017-097563.
doi: 10.1136/bjsports-2017-097563. [Epub ahead of print] Review.

Abstract

AIM:
To assess the relationship between time spent in light physical activity and cardiometabolic health and mortality in adults.

DESIGN:
Systematic review and meta-analysis.

DATA SOURCES:
Searches in Medline, Embase, PsycInfo, CINAHL and three rounds of hand searches.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES:
Experimental (including acute mechanistic studies and physical activity intervention programme) and observational studies (excluding case and case-control studies) conducted in adults (aged ≥18 years) published in English before February 2018 and reporting on the relationship between light physical activity (<3 metabolic equivalents) and cardiometabolic health outcomes or all-cause mortality.

STUDY APPRAISAL AND SYNTHESIS:
Study quality appraisal with QUALSYST tool and random effects inverse variance meta-analysis.

RESULTS:
Seventy-two studies were eligible including 27 experimental studies (and 45 observational studies). Mechanistic experimental studies showed that short but frequent bouts of light-intensity activity throughout the day reduced postprandial glucose (-17.5%; 95% CI -26.2 to -8.7) and insulin (-25.1%; 95% CI -31.8 to -18.3) levels compared with continuous sitting, but there was very limited evidence for it affecting other cardiometabolic markers including mortality. Three light physical activity programme intervention studies (n ranging from 12 to 58) reduced adiposity, improved blood pressure and lipidaemia; the programmes consisted of activity of >150 min/week for at least 12 weeks. Six out of eight prospective observational studies that were entered in the meta-analysis reported that more time spent in daily light activity reduced risk of all-cause mortality (pooled HR 0.71; 95% CI 0.62 to 0.83).

CONCLUSIONS:
Light-intensity physical activity could play a role in improving adult cardiometabolic health and reducing mortality risk. Frequent short bouts of light activity improve glycaemic control. Nevertheless, the modest volume of the prospective epidemiological evidence base and the moderate consistency between observational and laboratory evidence inhibits definitive conclusions.
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Re: Exercise, Health & You: How Much Is Enough?

Postby JeffN » Fri Jun 29, 2018 6:18 am

A simple "rule of thumb" to define brisk walking


How fast is fast enough? Walking cadence (steps/min) as a practical estimate of intensity in adults: a narrative review Br J Sports Med 2018;52:776-788.
https://bjsm.bmj.com/content/52/12/776

Abstract

Background
Cadence (steps/min) may be a reasonable proxy-indicator of ambulatory intensity. A summary of current evidence is needed for cadence-based metrics supporting benchmark (standard or point of reference) and threshold (minimums associated with desired outcomes) values that are informed by a systematic process.

Objective
To review how fast, in terms of cadence, is enough, with reference to crafting public health recommendations in adults.

Methods
A comprehensive search strategy was conducted to identify relevant studies focused on walking cadence and intensity for adults. Identified studies (n=38) included controlled (n=11), free-living observational (n=18) and intervention (n=9) designs.

Results
There was a strong relationship between cadence (as measured by direct observation and objective assessments) and intensity (indirect calorimetry). Despite acknowledged interindividual variability, ≥100 steps/min is a consistent heuristic (e.g, evidence-based, rounded) value associated with absolutely defined moderate intensity (3 metabolic equivalents (METs)). Epidemiological studies report notably low mean daily cadences (ie, 7.7 steps/min), shaped primarily by the very large proportion of time (13.5 hours/day) spent between zero and purposeful cadences (<60 steps/min) at the population level. Published values for peak 1-min and 30-min cadences in healthy free-living adults are >100 and >70 steps/min, respectively. Peak cadence indicators are negatively associated with increased age and body mass index. Identified intervention studies used cadence to either prescribe and/or quantify ambulatory intensity but the evidence is best described as preliminary.

Conclusions
A cadence value of ≥100 steps/min in adults appears to be a consistent and reasonable heuristic answer to ’How fast is fast enough?' during sustained and rhythmic ambulatory behaviour.



NY Times Article

PHYS ED
Walk Briskly for Your Health. About 100 Steps a Minute.
By Gretchen Reynolds
June 27, 2018

https://www.nytimes.com/2018/06/27/well ... steps.html

“For some people, it was 98; for others, 102, but 100 steps per minute is a good rule of thumb for almost everyone.”

"Vigorous walking requires about 130 steps per minute, she and her colleagues determined, a pace at which you still are walking. Jogging generally starts at about 140 steps per minute, she says. "
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