Revealed – how HIIT workouts can help ‘activate’ genes

Study finds anaerobic high-intensity interval training provides aerobic endurance benefits


In 1997, a Japanese professor called Izumi Tabata published a landmark study on endurance training that turned prevailing wisdom on its head.


He discovered that cyclists performing training sessions of 8 x 20sec high-intensity intervals with 10secs of rest in between (i.e. just 4mins of exercise) made the same gains in aerobic endurance as did those performing hour-long sessions of steady-state moderate-intensity cycling.

More recent studies on triathletes, swimmers and cyclists have indeed confirmed that small amounts of high-intensity interval training (HIIT) can indeed enhance endurance performance. This matters because short, intense interval sessions not only provide great performance returns, but are also relatively easy to fit into a busy training schedule.

But how can just 4mins of (anaerobic type) training provide the same aerobic benefits as an hour of aerobic type training? Recent advances in molecular biochemistry have allowed scientists to provide some answers; for example, we now know that repeated high-intensity efforts produces biochemical changes in muscle cells, which help ‘activate’ genes involved in aerobic energy production.

And for those who need further convincing, a newly published study suggests that HIIT really does deliver the endurance goods. Canadian scientists investigated the effects of a six-week training programme on 19 subjects who were split into two training groups: one performing HIIT (8 x 20sec intervals at 170% VO2max separated by 10secs for a total of 4mins); the other undertaking conventional training (30mins moderate intensity at 65% of VO2max).

It turned out that the gains in aerobic fitness were identical for both groups, as were the increases in muscle fibre oxidation and glycogen storage capacity, and other biochemical changes associated with increased endurance performance. In short, just 4min sessions of HIIT produced absolutely identical endurance adaptation as 30-minute sessions of conventional endurance training.

(Image: Jonny Gawler)


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