Exercise by the numbers

Fitness is essential for good health, but for optimal benefits you need to focus on the right exercise duration and intensity.

Any aerobic activity that gets the heart pumping helps you reach the proper intensity.
Image: ConnieTBallash/Thinkstock

The standard guideline for fitness, from both government agencies and health organizations, is 150 minutes of moderate-intensity exercise per week. "It does not matter how you reach those 150 minutes," says Dr. Elizabeth Matzkin, a sports medicine physician with Harvard-affiliated Brigham and Women's Hospital. "It could be 50 minutes three times a week, or 30 minutes five times a week, or some other combination. Even a short burst of 10 minutes at one time is beneficial."