There are a lot of competing recommendations out there about how much exercise people need to stay fit. This week, the Dept. of Health and Human Services released what it hopes is the definitive word on the subject with its "Physical Activity Guidelines for Americans."
These are based on "the first thorough review of scientific research about physical activity and health in more than a decade," and crafted by 13 advisory committee members appointed by HHS Secretary Mike Leavitt.
Without further ado, some highlights:
For adults, 2.5 hours a week of moderately intense aerobic activities, like brisk walking or gardening, is enough to yield big benefits. The 2.5 hours can be spread out over the week, but you need at least 10 minutes at a time to get your heart rate up.
Vigorous aerobic activity like jogging or jumping rope buys time: adults need only 75 minutes/week to stay healthy. You know it's vigorous if you can only say a few words before having to catch your breath.
Adults should also do muscle strengthening activities (lifting weights, sit-ups, carrying heavy stuff) 2 days/week.
Older folks should do as much as they can to meet the adult guidelines, and also do balance exercises if they are at risk of falling.
Pregnant women should follow the adult guidelines, though vigorous exercisers should talk to their doctors about whether they need to modify any activities.
Kids and adolescents need an hour or more of moderate or vigorous exercise at least 3x/week. They should do muscle strengthening and bone-strengthening activities (eg: running and jumping rope) 3x/week.
These are minimum guidelines. More exercise than this is, of course, better.