Short Bursts of High-Intensity Exercise Bring Measurable Improvement

Athletes have long added short bursts of high-intensity effort to their workouts to pump up muscle function and exercise performance, a topic I’ve written about before. New research reveals that this technique also measurably improves the structure and function of arteries, which is good news for cardiovascular health, since healthy blood vessels play an important role in transporting blood to and from the heart and all the other muscles and tissues in the body.

At McMaster University in Canada, researchers divided 20 participants (10 each healthy males and females with no known heart disease, average age 23) into two groups. One engaged in interval training with 30-second “all out” sprints, followed by four-and-a-half minutes of recovery with low-intensity cycling three times a week… and the other completed 40 to 60 minutes of moderate-intensity cycling five times a week. After six weeks, researchers found that both sprint exercise and endurance exercise training improved the ability of a main artery in the leg to dilate, with no measurable difference between the two exercise groups.

These findings suggest that brief, intense exercise can be just as effective as longer, traditional endurance exercise in improving arterial activity. Maureen MacDonald, PhD, an associate professor in the Department of Kinesiology at McMaster University and senior author of the study, told me that it seems that interval exercise — even very brief — results in beneficial changes that facilitate relaxation of the artery walls. Changes in the actual structure of the walls may also occur. Apparently you don’t have to endure long periods of hard work to improve your health.

Results of the research were published in the July 2008 issue of the American Journal of Physiology — Regulatory, Integrative and Comparative Physiology.


According to Dr. MacDonald, not only can this kind of higher intensity training be used by extremely fit people to achieve a new level in their training, it can also be a simple, efficient way to boost fitness for healthy people in search of a way to add variety to their training or who simply need to squeeze in shorter workouts. She adds that modified interval training has also shown great promise for people with medical problems who are unable to sustain higher exercise levels for long periods of time. Such people may benefit from shorter and less intense “sprint phases,” which may be easier for them to tolerate than the 30-second “all out” sprints performed in the study, says Dr. MacDonald.

Not everyone can do high-intensity interval training, as it is quite strenuous. (Check with your doctor if you are concerned about health problems that may make this dangerous.) But then again, not everyone needs to do it that way: What this study demonstrates is that exercise — either brief and intense or slow and steady — can be used to improve the function and structure of arteries and help keep your heart healthy. That’s a prescription just about everyone can follow.