FITT stands for:

Frequency (how often?),
Intensity (how hard?),
Type (what type of exercise?),
Time (for how long?).

It is a way to tell whether a person is working hard enough to benefit from a physical activity program. Each concept is applied to a physical activity, whether it is cardiovascular (biking, walking, swimming, jumping rope) or resistance training. The answers to the questions for which each letter stands will change as a person’s fitness level improves!