there are a number of different explanations as to why HIT seems to be more effective than endurance exercise. Firstly, exercising at low intensity only burn calories while yoy are active so that the minute you stop, you also stop burning calories. In contrast, high-intensity exercise continues to work on your metaborism a long time after you have finish - and this can be up to 24 hours later - so that you continue burning calories for longer. Secondly, HIT builds your muscles, replacing fat with muscle mass. The third theory is that the sprint-and-recover cycle doesn't give the body the change to store energy in the same way as training over a long period: the body needs to use all the energy in one go rather than maintain the same energy level over a longer period and still being able to reserve some as fat. The final theory is HIT combines both aerobic and muscle-strengthening activities and use many more muscles than regular exercise-up to 80% of the muscles in body, compared with up to 40% for moderate jogging or cycling
There have been numerous experiment into HIT. In one conducted by a team from the University of Colorado led by. Kyle Sevlts, five male volunteers were tested to measure the number of calories a typical HIT work out burns. The volunteers, aged between 25 and 31, were tested to make sure their hearts were healthy, and their body composition and resting metabolic