Sweat

Sweat a type of interval training in which you alternate short, very high-intensity intervals with longer, slower recovery intervals.

The idea is to work in the upper percentages of your target heart rate zone, or around a 9 out of 10 on the perceived exertion scale, meaning you go as hard as you can during the work intervals. This intensive effort takes you into your anaerobic zone, a level so high that your body can’t take in enough oxygen to the generate energy it needs for the activity.