How To Think About These Blood Pressure Changes...
Simple! Don't.
BP varies throughout the day all day long. Many, many variables can cause BP changes...such as time of day, stress levels, what you eat, how you feel, when you exercise and how hard, how hot you are or how cold, your emotions, your physical actiivity during the day, etc...
Stop worrying over BP and instead...
Do what is important!
Staying on the McDougall program 100%. You already know you have CVD issues and you need to heal them. The best way to do that is to be very strict on the program and more specifically I would recommend the Maximum Weight Loss program (MWL) along with Jeff's guidelines, principles and recommendations. Its the quickest way to heal yourself nutritionally. But you have to follow it strictly and continuously...for life if you expect the best results.
Stop worrying about whats not imporant and simply do what is. Follow the program 100% and come back in 3 months and tell us how you feel...and yes if you must, tell us your BP