Q. How much exercise should I do?
In addition to the National Academies’ Institute of Medicine’s recommendation of 60 minutes of daily exercise to prevent weight gain, there are two other major U.S. guidelines for how much physical activity you need:
- The American College of Sports Medicine recommends a five- to 10-minute warm-up and then 30 to 45 minutes of continuous aerobic activity (such as swimming, biking, walking, dancing, or jogging) three to five times a week, with a stretch and cool down period in the last five to 10 minutes. The ACSM also recommends weight training: at least one set (eight to 12 repetitions) each of eight to 10 different exercises, targeting the body's major muscle groups.
- The surgeon general recommends accumulating 30 minutes of moderate-intensity activity (hard enough to leave you feeling "warm and slightly out of breath") on most, if not all, days of the week. You can do it in two bouts of 15 minutes, three bouts of 10 minutes, or one bout of 30 minutes. This recommendation emphasizes incorporating activity into your daily life -- walking instead of taking the bus, parking your car farther from the mall and walking across the parking lot, taking stairs instead of the elevator, and washing your car by hand.
Q. I don't have time to exercise. I hate exercise. 60 minutes a day?
The 60-minute suggestion is based on the National Academy of Science's recommendation for people who are trying to prevent weight gain, or keep themselves from regaining after weight loss -- not for people who are trying to increase or maintain their cardio-respiratory fitness or health. There's plenty of research to show that 30 minutes of physical activity a day will help you gain lots of health and fitness benefits.
Both guidelines will help improve your health and fitness. Following the more vigorous ACSM recommendation will make you more aerobically fit, and its strength-training component will make you stronger and more toned. The Surgeon General guideline, meanwhile, may be easier to fit into your lifestyle -- not replacing the ACSM guideline, but complementing it.
If you already exercise vigorously at the gym several times a week, there's no reason to quit. But if the ACSM recommendation is too much for you, the Surgeon General's report offers you an alternative.
The most important thing is that you do something.