Circuit training is a form of strength training that entails moving through a series of different exercises with very little rest between sets. It is true that circuit training has some aerobic benefit, but the benefit really depends on your fitness level and goals.

If increasing aerobic capacity is your goal, circuit training probably isn't your best bet. One study showed that doing 20- to 30-minute circuit training workouts 3 times a week for 20 weeks improved aerobic capacity by about 7 to 8 percent. This is only about one-third the improvement that would be expected from traditional cardiovascular workouts such as running, cycling and stair climbing.

However, if you are satisfied with your aerobic fitness level, circuit training may be a good maintenance strategy for you. Evidence suggests that circuit training can be used to maintain improvements that have been already been achieved through conventional cardio exercise.