A total body workout during your lunch hour? With circuit training, it's possible. During circuit training, you perform a series, or "circuit," of weight-training exercises (or "stations") using low weights and high repetitions with minimal rest between sets, to keep the workout intensity—and your heart rate—up. If you organize your circuit effectively and move quickly from station to station—no waiting for equipment or resting between push-ups—you'll reap an excellent combination of strength, aerobic, and anaerobic benefits in less than a 30 minutes…