Speed and resting time Hing Intensity Interval Training (HIIT) refers to doing almost any type of exercise at a variable pace. For example, if you are walking or doing push-ups, vary the pace of the exercise. You can walk normally for a minute or so, and then speed up a bit, and then return to normal speed several times. For exercises like push-ups, do a few slowly and do others more quickly and, like walking, repeat these faster and slower intervals several times. Interval training helps the...