The Dangers of Sitting Too Much

by Dr. Gabe Mirkin, M.D.

The average adult spends more than 90 percent of his waking hours sitting down. A study followed 222,500 men and women for three years, and found that compared to those who sat for fewer than four hours a day:

* those who sat for at least eight hours a day were 15 percent more likely to die in that time, and:

* those who sat for 11 or more hours a day were 40 percent more likely to die in that time (Arch Intern Med, March 26, 2012; 172(6):494-500).

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A review of the scientific literature shows that time spent sitting increases risk for chronic disease. Thirty minutes of physical activity is as protective as 10 hours of sitting is harmful (Exerc Sport Sci Rev. 2010;38(3):105-113). The more time you spend sitting, the less time you spend moving your muscles (Eur Heart J. 2011;32(5):590-597).

THIRTY MINUTES OF EXERCISE THREE TIMES A WEEK IS INADEQUATE FOR HEALTH:

We now know that exercising for only 90 minutes a week leaves 166.5 hours a week for inactivity, which is harmful to your health. People who sit for long periods are sicker, fatter and are more likely to die of heart attacks.

A LITTLE EXERCISE DOES NOT PREVENT THE HARMFUL EFFECTS OF PROLONGED INACTIVITY: A study from Finland showed that exercise does not prevent the harmful effects of prolonged sitting (Scandinavian Journal of Medicine & Science in Sports, March, 2012). Twenty-seven Finnish men and women exercised on one day and rested on the next. They wore special equipment which demonstrated that their muscles were inactive 70 per cent of the day whether they exercised or not. They spent the same amount of time sitting down on days they exercised for 30 to 150 minutes as they did when they did not exercise.

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RESTING MUSCLES ARE INERT

Contacting muscles help to clear your bloodstream of sugar and fat, thus helping to prevent heart attacks, strokes, diabetes, cancers, and premature death. A high rise in blood sugar causes sugar to stick to the outer surface of cell membranes and destroy the cell. Resting muscles require insulin to prevent this high rise in blood sugar. Contracting muscles remove sugar and fat from your bloodstream without needing insulin. When you spend a lot of time sitting, your blood sugar and fat levels rise too high, which can damage your arteries and every other cell in your body.

THE BENEFITS OF CONTRACTING MUSCLES LAST ONLY UP TO 17 HOURS

A muscle's ability to extract sugar and fat from your bloodstream without needing insulin is maximal during exercise and only for up to an hour after you finish exercising. This benefit rapidly declines to disappear completely in fewer than 17 hours.

THE MESSAGE FOR YOU: Try to exercise every day and try to avoid sitting for prolonged periods of time.