Exercise time or duration refers to the span of time during which exercise is performed, not including warm-up and cool-down. To benefit an exercise program, proper duration depends on many factors including total work to be done, exercise intensity, frequency of exercise, fitness level and goal. To gain cardiorespiratory benefits, duration may vary from five to 45 minutes per session. In unconditioned people, positive training effects have been seen with three to five minute periods of daily exercise. However, a duration of 20 to 30 minutes is more optimal.

High-intensity training can significantly improve physiologic capacity with 10 to 15 minute exercise periods per workout. Conversely, a 45-minute exercise period may be required to produce a training effect when exercise intensity is below the threshold heart rate (50 percent MHR). Lower-intensity exercise is offset by increased duration of training.

The basic duration guidelines are:

For the goal of fat loss, duration is increased only past the upper end of the beginner’s level (20 min.) if true physiologic adaptation has been reached or further compliance to proper food intake can’t be achieved. Exercise duration is the second component to be manipulated following intensity. Always adhere to the least amount of specific work required.