Sprint better than marathon

Exercise is important for preventing cardiovascular disease, especially in children and adolescents, but is all exercise equally beneficial?

New research published in the American Journal of Human Biology reveals that high-intensity exercise is more beneficial than traditional endurance training.

“Cardiovascular disease is a leading cause of mortality throughout the world and its risk factors have their origins in childhood,” said lead author Duncan Buchan from the University of the West of Scotland. “Our research examines the effects of brief, intense exercise when compared to traditional endurance exercise on the markers of cardiovascular disease in young people.”

Mr. Buchan’s team recruited a group of volunteer schoolchildren, 47 boys and 10 girls, and randomly divided the group into moderate and high-intensity exercise teams.

The two groups performed three weekly exercise sessions over seven weeks. The high-intensity group’s training consisted of a series of 20-metre sprints over 30 seconds, while the moderate intensity group ran steadily for 20 minutes.

By the end of the study, the moderate intensity group had completed 420 minutes of exercise and the high-intensity group had trained for a shorter 63 minutes. The estimated energy expenditure for the high-intensity intervention was 907.2 kcal in comparison to 4,410 kcal for the moderate-intensity group.

The results revealed that both groups demonstrated improved heart disease risk factors. However, the total exercise time over seven weeks was six times higher for the moderate group compared to the high-intensity group. Thus, significant improvements in cardiovascular disease risk factors in the high-intensity group occurred in only 15 per cent of the total exercise time. These findings demonstrate that brief, intense exercise is a time-efficient means for improving heart disease risk factors in adolescents.

Although limited to relatively small samples, the findings demonstrate significant improvements in cardiorespiratory fitness, blood pressure, body composition and insulin resistance in healthy adolescent youth after a seven-week intervention of different exercise intensities.