How Much Do I Need to Do to Gain All These Benefits?

It doesn't take all that much aerobic exercise to accrue lots of fitness and health benefits. There are two physical activity recommendations to choose from in the United States. One is the Surgeon General's "lifestyle" recommendation, where you can accumulate activity and incorporate it into your day (a nice way to save time for busy people), and then there's the formal "workout" recommendation from the American College of Sports Medicine (ACSM).

1. Surgeon General: The Surgeon General recommends 30 minutes or more of accumulated moderate intensity physical activity on five or more days per week to improve health and fitness. "Accumulated" means you can do it in shorter bouts throughout the day (for example, 10- or 15-minute intervals throughout the day), and "moderate intensity" means you feel warm and slightly out of breath when you do it. You can read more about the Surgeon General's "lifestyle" recommendation at: www.cdc.gov/nccdphp/sgr/sgr.htm.

2. ACSM: The American College of Sports Medicine recommends 20-60 minutes of continuous activity, three to five times a week, at 60-90% of maximum heart rate, and two to three days of resistance training. You can read more about the ACSM formal workout recommendation at: www.acsm-msse.org/pt/pt-core/template-journal/msse/media/0698a.htm.

Both recommendations include aerobic exercise, and your health and fitness will improve if you follow either. Choose the Surgeon General's lifestyle recommendation if you are unable or unwilling to follow the ACSM workout recommendation, and stick with the ACSM recommendation if you're already putting in time at the gym or you like the buzz of vigorous exercise. Of course, incorporating lifestyle activity and formal workouts into your exercise plans will give you the best of both worlds.