the exerciser's point of view, it shouldn't matter, as long as the intensity is achieved. The advantage of this approach is the small time commitment required. Clear benefits in terms of aerobic fitness and insulin sensitivity have been observed with just nine minutes of exercise a week (or 90 minutes total time commitment when you include rest). But this method of training typically involves specialised equipment (such as electromagnetically braked stationary lab bikes) and due to the very high exertion and motivation required it may not be feasible for the general population. Aerobic HIIT Aerobic HIIT sessions on the other hand typically involve four to six four-minute repetitions of exercise performed at 80-90 per cent of the maximum aerobic exercise intensity. These efforts are interspersed with one to three minutes of recovery with a single session taking up to 38 minutes. Low-volume maximal HIIT This strategy involves eight to ten one-minute bouts performed at maximal aerobic exercise capacity, interspersed with 60-75 seconds of light recovery, therefore offering significant time advantages, with a single session taking around 20 minutes. Therefore its lower intensity (compared to supra-maximal HIIT) and shorter session duration (compared to aerobic HIIT) may make it suitable for sedentary or obese people, and those with existing metabolic conditions. How low can you go? We still don't really know the minimum amount of exercise required to induce significant health and fitness benefits. But a recent study has cut down the exercise time even further, showing that just six ten-second all-out