Wednesday, March 9, 2011

When Exercise is Bad for Your Heart

Several friends have sent me links to a scientific study that hit the media this week as a means to justify their sedentary lifestyles...as in, "See I told you exercise is bad for you!"

The study looks at medical images of the hearts of competitive endurance athletes more than 50 years of age.  Turns out, those athletes that had exercised the most over their lifetime had more damage to their heart muscle.  Is that a reason not to exercise???

Alas my friends, no.  It suggests that you may not want to become an ultra-marathoner over a lifetime.  It suggests that if you are an ultra-marathoner or if you consistently exercise hours a day every day over a lifetime that you may want to talk to your physician about your heart.  But it doesn't mean you should not exercise at all.

This study illustrates something Dr. Dorks refer to as "the therapeutic window".  In normal-people-talk, this translates to "get what you need, no more/no less".  Here is the concept:

Too little of X: Bad
Just the right amount of X: Good
Too much of X: Really bad

The "just the right amount" category is known as the therapeutic window.  It's the amount that you need of 'X' for optimizing health. 

In the world of nutrition, there are several examples of 'X': exercise, folic acid, vitamin D, beta-carotene, vitamin E, dietary fat, alcoholic beverages....to name a few.  In the case of exercise, too little exercise is associated with things like obesity, constipation, depression, loss of muscle mass, etc.  And too much exercise has been shown to suppress the immune system, resulting in more colds and flu, and now heart damage.  It's best to stay in "the therapeutic window" and follow the recommendations which suggest 30-90 min of daily physical activity most days of the week.

Vitamins and minerals are very similar.  Little can be gained by taking too much of any one nutrient, despite what the bottle or some website tells you.  In some cases, having too much of a nutrient is worse than not having enough.    
I'm off to enjoy what I know will be the "therapeutic window" with some girlfriends in the mountains.  This is what happened last year when I was with them:



I did strange facial expressions and weird things with my hands.  This year, I hope to avoid looking like an idiot....at least in front of the camera.  But of course I was, am and always will be a giant Dr. Dork...in Chicago or Wyoming.      

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