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. On a 1-10 scale of perceived exertion, high intensity can be considered anything over an effort level of 7. When using max heart rate (MHR) as a guide, high intensity can be considered exercising above 80% of MHR. 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. 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.
Gellish et al. formula for MHR: 206.9 – (0.67 X Age)
What is a typical HIIT session like?
A 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. Once the body is warmed up, it is then time to begin the work intervals. The appropriate work to recovery ratio for HIIT is 1 minute of work to every 2 to 3 minutes of active recovery. 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. Start with a lower number of work intervals and work up to doing 10-12 high intensity work intervals.
Sample 30-minute HIIT Workout
5-minute warm-up – moderate jog
8 intervals – 30-second sprints, followed by a 1 -2 minutes recovery walk or slow jog
5-minute cool-down – walk and stretch
Sample Outdoor HIIT Workout
5-minute warm-up – moderate jog, Running at the fastest pace possible on a track for 200 meters, then jogging at a slower pace for 400m (or twice the length of time required to run the 200 meters). 5-minute cool-down – walk and stretch.