The Centers for Disease Control and Prevention defines moderate-intensity exercise as activity that burns approximately 150 calories a day. You can achieve moderate-intensity aerobic activity in several ways and gauge how hard to push yourself by:
- Choosing any of these activities: walking at 3 miles per hour or faster, bicycling at 10 miles per hour, water aerobics, doubles tennis, or ballroom dancing.
- Taking at least 100 steps per minute when you walk. If you don't walk regularly, start with 1,000 steps in 10 minutes and build up to 30 minutes.
- Using the talk test. You should be able to talk comfortably when working out, but singing should make you catch your breath. Your breathing and heart rate should rise noticeably.
Work out at least 30 minutes a day, five days a week (150 minutes total). If you haven't exercised for the past several months, exercise for the same amount of time but at a lower level of intensity. You can split up your workouts, too. If you can't exercise for 30 to 60 minutes at one time, do shorter bursts for at least 10 minutes. In addition to aerobic exercise, you should do strength training for major muscle groups two or more days a week, as well.
Source: Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50