<human>:  What is the difference between HIIT and HIIT?
<bot>: The first one is High Intensity Interval Training, and the second one is HIIT. HIIT is a type of exercise that alternates periods of intense exercise with less intense exercise. The goal is to perform the more intense exercise at a pace that causes the heart rate to reach a maximum level for a short period of time, then lower the intensity to a lower level for a longer period of time.