The word is out about the benefits of exercise.  Some recent publications (e.g., US Department of Health and Human Services: “Physical Activity Guidelines for Americans”) have put some numbers to it.

First, some definitions.  The guidelines speak to “moderate physical activity” and “vigorous physical activity.”  The former includes brisk walking and everyday activities such as mowing the lawn, carrying groceries, easy bike riding, etc.  The latter refers to more vigorous activity such as jogging, running and fast biking.  The key is to do something that increases heart rate and makes breathing a bit harder.  How do you know which is which?  If you can talk while exercising, but not sing, you are probably doing moderate activity.  There is a spectrum of activity, and the more you do, the better.  Two minutes of moderate activity equals approximately one minute of vigorous activity, and whatever is done should include some resistance training at least twice a week (i.e., anaerobic work), such as weight lifting.

The Numbers 

Numerous observational studies that include millions of individuals demonstrate rather dramatic data.  One meta-analysis (i.e., a paper that combines research from several similar studies) demonstrated a 60% reduction in all cause mortality in people who did about 150 minutes per week of moderate activity compared to people who did little or no exercise.  Even 10 to 15 minutes of activity per day resulted in a 45 to 50% reduction in mortality.  A trial of previously sedentary people who undertook moderate activity achieved a 20% reduction in mortality compared to those who remained on the couch. 

It goes on and on, and data show that any level of activity, in terms of reducing risk of a multitude of causes of death, is superior to just sitting around.  The sweet spot is 150 minutes per week of moderate activity or 75 minutes of vigorous activity per week, but benefit accrues on a continuum that starts with something as simple as standing rather than sitting (you burn almost 25% more calories while standing).  So the elderly and/or infirm can benefit from exercise even if 150 minutes of activity per week is impossible.  And there appears to be no upper limit–the more you do, the greater the benefit. 

Finally, what if you cannot do exercise every day?  Can you cram your 150 minutes into, say, the weekend, and still achieve the benefit?  Resoundingly, the answer is YES.

Comment

The benefit of exercise is so striking that I wonder how it compares to statins.  I would love to see a trial that compares statins to exercise (Pause here while pharmaceutical executives pick themselves up from the floor).

At any rate, the benefits of exercise are even more amazing, and manageable, than I knew.  In the words of the late, great Cubs announcer, Harry Caray, “Holy Cow!”