Researchers at the University of Copenhagen have found that short sharp bursts of exercise lasting 30 seconds, but repeated a number of times in a single session, improves fitness more than performing steady state exercise over prolonged periods of time.

Traditionally the theory went that to improve fitness and burn body fat exercisers should exercise at a relatively low level of their Age Predicted Heart Rate Maximum, of APHRM, when working out. However, exercise science research seems to suggest that the best way to increase fitness AND burn fat is to perform repeated sprint type exercise where the exerciser works between 90 to 100 percent all out exercise for between 15 to 30 seconds, followed by 'active rest' of 45 to 90 seconds, followed again by the sprint, with teh cycle repeated 6 to 20 times (shorter sprints being repeated more than longer sprints).

Scientists believe that the effect behind these improvements are related to the amount of potassium in cells of the muscles, which is vital for muscle movement. Intense bursts of exercise result in higher potassium levels in muscle tissues, with this increased level of potassium being able to help muscles respond quicker and allowing the performer to move faster.

It is also suggested that intense exercise is little to improve muscle tone and strength, which in turn increases the metabolism, the body's fat burning engine, as well as increasing the anaerobic threshold, the point at which exercise becomes uncomfortable and less sustainable.