FRIDAY, April 8 (HealthDay News) -- All exercise is the same, right? Not so fast, suggests a small study of teens out of Scotland that found that high-intensity exercise may be better than endurance training for preventing cardiovascular disease because it can be done in less time.

The study included 57 adolescent schoolchildren (47 boys and 10 girls) who were randomly assigned to high-intensity or moderate-intensity exercise groups.

Both groups did three exercise sessions a week for seven weeks. The high-intensity group's program consisted of a series of 20-meter sprints over 30 seconds, while the children in the moderate-intensity group ran steadily for 20 minutes.

By the end of the seven weeks, teens in the moderate-intensity group had completed a total of 420 minutes of exercise, compared to 63 minutes for those in the high-intensity group. Estimated total energy expenditures per child were 4,410 kcal for those in the moderate-intensity group and 907.2 kcal for those in the high-intensity group.

Both groups of children showed significant improvements in cardio-respiratory fitness, blood pressure, body composition and insulin resistance. But the teens in the high-intensity group achieved those health benefits with only 15 percent of the exercise time put in by those in the moderate-intensity group.

The findings, published April 5 in the American Journal of Human Biology, suggest that brief, intense workouts offer a time-efficient way to reduce cardiovascular disease risk factors in teens, said study author Duncan Buchan, of the University of the West of Scotland, and his colleagues.

However, further research is needed, they added.

More information

The U.S. Centers for Disease Control and Prevention outlines recommended amounts of exercise for children and teens.