These recommendations include at least 60 minutes of moderate-intensity aerobic exercise a day, such as brisk walking, plus high intensity activity three times a week.

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The 2008 Physical Activity Guidelines for Americans released by the Department of Health and Human Services recommends that adults age 18 to 64 engage in at least 2.5 hours of moderate-intensity aerobic exercise (brisk walking, biking) or an hour and 15 minutes of vigorous activity (like running) each week.

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Strength training, aerobic exercise and stretching can prevent muscles from withering, reduce disability and even reduce pain intensity by 10% to 50%, Rainville says.

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