How much exercise is needed to effectively manage stress and prevent diseases such as coronary heart disease and hypertension?
By: Andrew Wolf, M.S. E.D.
When you think about exercise in regard to disease prevention it is important to keep in perspective the simplicity of exercise. If you think about it all exercise can be broken down into how many calories you burn when you do that exercise. It is important to think of exercise this way because when you want to talk about “how much exercise” you are really asking “how many calories”. The other thing to keep in mind is the unimportance of what you do today and the importance of how much you have done this week. Think of exercise as an accumulation of calorie burning that occurs over seven days not whether or not you did 30-45 minutes on the treadmill today.
Keeping this point in mind I always try to get my clients to think about exercise accumulation. Doing three bouts of exercise that are 60 minutes long or doing 18 bouts of exercise that are 10 minutes long is the same thing when it comes to burning calories and preventing disease. Both approaches have you doing 180 minutes of exercise per week so in the end they are equal.
In regard to what kind of exercise I would probably suggest that most of it be cardiovascular exercise simply because it burns more calories per minute than pumping iron. This does not address the issues of bone density, posture, and strength but that is another topic for another day. When I am in the weight room lifting I usually burn anywhere from 3.5-5 calories per minute so 45 minutes of lifting usually yields 191 calories burned. If you catch me riding my bike at home at 145 beats per minute I am usually burning about 14-16 calories per minute so 45 minutes gives me 675 calories.
Now where does the calories/disease axis come in? Well when it comes to preventing coronary artery disease and diabetes I am usually trying to get my clients to get as close to burning about 2000 calories per week as they can. This can be a pretty tall order so I try to make this a long term goal, not something that you throw yourself into right away. This is also why I try to get my clients to think about how they are doing their cardiovascular exercise. The bottom line is simply this: you get more or less fit every 3 weeks. If you relax for 3 weeks you get less fit and burn fewer calories when you work out, if you challenge yourself for 3 weeks you get more fit you burn more calories. The good news is the more fit you get the less time it takes to burn the calories. Another good reason I try to get my clients to use a heart rate monitor.
When it comes to making a dent in blood pressure I am not so stringent. I am trying to get most of my clients to burn 1000+ calories per week with exercise. The problem with hypertension is that your blood pressure responds to the exercise you have done in the last 2 -3 days. This creates a situation where exercise should be done on as many days as possible in order to manage this silent killer.
On the stress issue this is a little hard to nail down but here is something I always like to think about. Your heart is covered in these little stress receptors called Beta receptors. The more Beta receptors you have the less stressed you have to be before your heart reacts. Increased fitness is accompanied by a reduced number of Beta receptors on the heart. In essence you become thicker skinned and harder to physically fluster the more fit you are.
What does it take to burn 100, 1000, 2000 calories per week. Bottom line is that most people burn about 100 calories per mile of walking or running regardless of speed. You burn calories faster when you run but it takes less time to finish the mile and vice versa for walking. Add about 10-15 percent for hills and such.
We have couched this conversation in terms of exercise and calories burned now you can think about it in terms of time spent. When you do that you will see why, when I am in consults here at Miraval, I am always trying to get my clients fitter. The fitter you are the less time it takes to prevent disease!