Experts believe that physical activity participation in youth can promote good health into adulthood. According to a recent study, one way youngsters can reduce cardiovascular disease (CVD) risk factors is to participate in brief periods of high-intensity exercise (HIT). The study subjects included 47 boys and 10 girls who were approximately 16.4 years of age. They were separated into three groups: high intensity, moderate intensity and control. Body composition, body mass index (BMI) and blood pressure measurements were taken pre- and post-intervention, and a health questionnaire was administered. Individuals in the HIT group performed 30 seconds of maximal-effort sprint four times with a 30-second rest between each sprint; they did this three times per week. As the weeks progressed, so did the exercise protocol. By week 7 the HIT group was performing 6 repetitions with a 20-second rest between each sprint.

The moderate-intensity group exercised at 70% VO2max for 20 minutes three times per week.

According to the data, the moderate-intensity group experienced improvements in BMI, body fat percentage, systolic blood pressure and HDL and LDL cholesterol levels. The HIT group saw minimal—if any—improvements in BMI and body fat percentage. However, the HIT group showed significant improvement in systolic blood pressure. Cholesterol readings showed greater improvements among the HIT group than among the moderate-intensity group.

The study authors stated, “It is not surprising, perhaps, that traditional endurance exercise [the moderate-intensity intervention] appears to have had the greatest effect on CVD risk over the 7-week intervention,” but they concluded that “brief, intense exercise is a time efficient means for improving CVD risk factors in adolescents.”

The study was published in the American Journal of Human Biology (2011; doi: 10.1002/ajhb.21166).