If you want to improve your health you don't have to spend hours slogging away at the gym, say experts. In fact short bursts short bursts of intense exercise could be just as good at helping prevent heart disease.
That's the verdict of a study published in the American Journal of Human Biology, which followed the exercise patterns of 57 schoolchildren over the course of seven weeks. The volunteers were split into moderate and high-intensity exercise groups, and took part in three exercise sessions each week.
Both groups concentrated on running as their main form of exercise, with the high-intensity group taking part in fast, intense but short springs, and the moderate group running for 20 minutes at a time.
At the end of the study period, the moderate group had exercised for 420 minutes - whereas the high-intensity group had only worked out for 63 minutes.
Unsurprisingly, the moderate group burned loads more calories - four times as many as the high-intensity group. But both groups displayed improvements in health factors such as blood pressure, insulin resistance and cardiorespiratory fitness, all of which benefit the heart.
So if you're working out because you want to lose weight, long, sustained exercise sessions may be the way forward, as you'll burn more calories. If you simply want to improve your health, on the other hand, the research suggests short, sharp bursts of exercise are equally as effective as working out for longer periods.
Why do you exercise? To be healthy, or to look good?