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Asked by Lori Wilson, Menomonee Falls, Wisconsin
No one has been able to answer this question for me. Is it better to exercise hard for a short period of time, or is it better to exercise moderately for a longer period of time? For example, let's say you can exercise hard for 10 minutes before your body makes you stop, but you can exercise moderately for 30 minutes or more. Which is better?
Diet and Fitness Expert
Dr. Melina Jampolis
Physician Nutrition Specialist
Hi Lori
The 2008 Physical Activity Guidelines for Americans released by the Department of Health and Human Services recommends that adults age 18 to 64 engage in at least 2.5 hours of moderate-intensity aerobic exercise (brisk walking, biking) or an hour and 15 minutes of vigorous activity (like running) each week. So with these guidelines in mind, the answer to your question depends on your exercise goals.
For heart health, it is probably better to exercise moderately for at least 30 minutes five times per week. For improving fitness levels, it may be better to exercise harder for a short period of time.
I think the best approach for health, fitness and weight loss includes exercising at a variety of intensities each week (doing one or two longer, moderate-intensity workouts and several shorter, more intense workouts) or incorporating interval training into your workouts. Interval training involves alternating periods of moderately intense exercise that last one to three minutes with short, more intense exercise periods lasting from 30 seconds to a minute.
By alternating high- and low-intensity exercise during the same workout, you are able to exercise at a higher overall average intensity, burn more calories and improve fitness. This type of training can also help prevent weight loss plateaus, which often occur during weight loss accompanied by exercise because the fitter or trimmer that you are, the fewer calories you burn doing the same workout.
I recommend that my patients incorporate interval training at least twice a week for 20 to 30 minutes. No special equipment is needed (although a heart rate monitor can be helpful for gauging how hard you are working) and interval training can be done either outdoors or indoors.
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