The excuse that there is not enough time to exercise effectively is beginning to wear thin according to evidence from a study by scientists in Canada who found that short term high-intensity interval training (HIT) can deliver in significantly less time the same health benefits as moderate long term "endurance" training.

The scientists who did the study are based at McMaster University, Hamilton, Ontario. A paper on it is about to come out in print in the The Journal of Physiology, although an online issue has been available to view since January.

Scientists have known for years that doing regular moderate long term exercise like cycling or running for several hours a week improves oxygen delivery to muscles and elimination of waste products: it also improves the efficiency of fuel burning in the tiny power houses inside cells, the mitochondria.