High-intensity vs. endurance workout--which is the victor?

Endurance training and high-intensity workouts--do both offer cardiovascular benefits? A study finds that each form of exercise has health benefits, with intense workouts perhaps edging out the competition.

The study focused on a group of 47 adolescents (average age about 16) who were assigned to a moderate exercise group, a high-intensity exercise group or a control group for seven weeks. The moderate exercise group did 20 minutes of steady running three times a week, while the high-intensity group did four to six repeats of an all-out sprint with brief recovery periods three times a week.

Both groups showed evidence of cardiovascular benefits at the end of the study. The high-intensity group had substantial improvements in systolic blood pressure, aerobic fitness and body mass index. Among the moderate-intensity group's improvements were aerobic fitness, body fat percentage, body mass index and insulin concentrations. No injuries were reported.

The moderate-intensity group burned more calories than the high-intensity group: 4,410 versus 907 on average. But the study authors noted that the high-intensity group exercised for a total of only 63 minutes, 15% of the 420 minutes spent by the moderate-intensity group.

Most exercise experts recommend that workouts include both endurance and interval training, which can be done outside or in a gym.

Although this was a small study, lead author Duncan Buchan of the University of the West of Scotland was optimistic about the implications of the results: "This is the first study to demonstrate the effects of a novel interval training program on both traditional and novel (cardiovascular disease) risk factors in adolescents," he said in a news release. "Larger scale and extended interventions must be undertaken so that the long term impact and effects of intermittent training programs on unfavorable metabolic profiles may be investigated further."

The study was released Wednesday in the American Journal of Human Biology.
Source: Jeannine Stein, Los Angeles Times; 4/6/11