"The message should always be to take it slow by setting realistic but challenging goals," says Jack Rejeski, Wake Forest University professor of health and exercise science. He recommends a walk with friends "and before you know it, you're through."
Some tips:
--The recommendation is for moderate-intensity physical activity, things like a brisk walk, water aerobics, cutting grass with a push mower, taking a dance class, doubles tennis.
--Just doing 10 minutes at a time counts. A few 10-minute activities each day add up.
--If you've been sedentary, build up gradually.
--If you prefer more vigorous activity -- like jogging or singles tennis or a fast bike ride -- the Centers for Disease Control and Prevention says 75 minutes a week is sufficient. One minute of vigorous activity counts for two minutes of moderate activity.
--The CDC says moderate-intensity means you're not breathing too hard to talk but you couldn't sing.
--In addition to the aerobic activity, the CDC urges muscle-strengthening activities at least two days a week. That can range from digging in the garden and yoga to push-ups or lifting weights.