Staying active during the recovery period allows the muscles to remove the metabolic waste and produce more energy for the next bout of high intensity exercise. The appropriate work to recovery ratio for HIIT is 1 minute of work to every 2 to 3 minutes of active recovery. Once the body is warmed up, it is then time to begin the work intervals. HIIT training calls for challenging work-rates such as sprints (whether on a bicycle or running) for short time frames lasting from thirty seconds to two minutes.Ī typical HIIT session would call for a warm-up of 5-10 minutes where the intensity gradually increases from a RPE of 3 to a RPE of 5. Modes of HIIT can include outdoor activities such as running or cycling, or using equipment such as treadmills, elliptical runners, stair-climbers or stationary bikes. When using max heart rate (MHR) as a guide, high intensity can be considered exercising above 80% of MHR. On a 1-10 scale of perceived exertion, high intensity can be considered anything over an effort level of 7. High Intensity Interval Training (HIIT) is a system of organizing cardiorespiratory training which calls for repeated bouts of short duration, high-intensity exercise intervals intermingled with periods of lower intensity intervals of active recovery.