Duration
	The length of each of your workout sessions depends on your fitness goals, the intensity of your workout, your current fitness level, and the commitments and demands in your life.
	Obviously, the longer you run or lift, the more calories you will burn. However, there becomes a point where over exercising will cause more damage than good. A well developed program should take you no longer than 45 minutes a day.
	Strength Training
	20 - 45 minutes of properly performed exercises.
	Cardio Training
	For health benefits, a minimum of 20 minutes per session is recommend three times per week.
	For weight-loss exercise, 30-45 minutes per session three times per week.
	Interval Training is a cardio training session where you go from very high to very low intensities, all in one session. The beauty of this type of training is that almost no muscle is lost as a result. Studies have shown that intervals lasting a total of 15 minutes were more effective in changes of body composition than longer sessions (30-60 min) of regular moderate intensity exercise.