Lifetime Fitness: The Benefits of High-Intensity Exercise

New Research Supports The Benefits of High-Intensity Interval Training

Now there’s more research affirming the value of the high-intensity interval training you learned at Pritikin.

Scientists recently concluded that high-intensity intervals (one- to two-minute bouts of vigorous aerobic exercise at the high end of one’s target heart rate zone alternated with low-intensity bouts) were a safe alternative to traditional cardiac rehabilitation for people with coronary artery disease who are basically in good condition.

Moreover, interval training provided additional benefits, particularly stronger muscles, which, the authors reported, would be especially helpful for the performance of many activities of daily living, from carrying grocery bags to playing with children and grandchildren.*

In the 16-week study, researchers from the University of British Columbia in Vancouver put seven highly functional men with coronary artery disease on a traditional cardiac rehabilitation program: a 10-minute warm-up, 30 minutes of aerobic exercise at moderate intensity (65% of maximum target heart rate), and a 10-minute cool-down.

Seven additional men, also highly functioning heart disease patients, used the same warm-up and cool-down, but their workout period involved two-minute bouts of intensity exercise (85 to 90% of maximum target heart rate) followed by two-minute low-intensity phases (40% of maximum).

Improvements in aerobic fitness for the two groups were similar, but the high-intensity group achieved markedly greater improvements in anaerobic performance – “without increasing risk to the patient,” concluded lead investigator Darren E.R. Warburton, PhD, of the School of Human Kinetics at the University of British Columbia.

Anaerobic literally means “without oxygen,” that is, a level of activity where for brief periods of time the body’s demand for oxygen exceeds the body’s ability to supply oxygen.

Interval training works both your aerobic and anaerobic systems, and the benefits are amazing. Intervals help you burn extra calories because your muscles are working harder, which means intervals may help you break through plateaus you’ve hit in your efforts to lose weight.

Intervals also do a great job of helping you retain muscle while losing fat. The more muscle mass you have, the more calories you burn, and the leaner you get – in all areas of your body, including those hard-to-shed-fat areas like the stomach, hips, and butt.

Remember: Do not interval train every day. Make sure you do intervals on nonconsecutive days because your body needs a minimum of 48 hours to repair, replenish, and rebuild muscle tissue. You’ll reap all of interval training’s benefits with just two to three 30-minute sessions weekly.

In another just-published study, interval training was proven to vastly improve aerobic endurance in out-of-shape people in much less time, just two weeks, than longer, steady, moderately-paced workouts.**

* American Journal of Cardiology, 2005; 95: 1080
** Journal of Applied Physiology, 2005; 98: 1985

---