Short bursts of exercise could be just as good at helping prevent heart disease as longer endurance sessions, research suggests.

Fast but intense sprints could help limit the risks linked to heart disease just as effectively as longer, 20-minute runs, according to a study on teenagers.

Some 57 boys and girls were split into three groups for the research, published in the American Journal of Human Biology.

All children performed three weekly-exercise sessions over a period of seven weeks.

The first group worked at moderate intensity,with 20 minutes of continuous running within a 20-metre area at 70 per cent maximum oxygen uptake.

The second high intensity group repeated sprints as fast as they could within a 20-metre area, with 20 to 30 seconds recovery in between, while the third group acted as a control.

The total time spent exercising was 420 minutes for the MOD group and 63 minutes for the HIT group.

Those in the MOD group burned more than four times as many calories but both groups saw improvements in factors that could lead to heart disease.

In the HIT group there were significant improvements in blood pressure, aerobic fitness and body mass index.

In the MOD group, there were significant improvements in aerobic fitness, percentage body fat, body mass index and levels of insulin.

Overall, traditional endurance exercise appeared to have had the greatest effect on heart disease risk over the seven weeks.