The duration of rest is highly variable depending on volume, intensity, and a person’s general fitness level. For example, if an individual starts with a large amount of muscle mass, which generally requires a longer time for recovery to rebuild the muscles damaged from the workout. Whereas individuals who have less muscle mass will not require as long a duration of rest between workouts. A good rule of thumb is that your goal should be one full day of rest for every day spent working out in high-intensity intervals or training sessions. For example, if you work out twice on Monday and work out again Tuesday at heavy intensity, you should aim to take two days off before doing another heavy workout Wednesday.