ANDREA KOPPEL, CNN ANCHOR: And, timing your workout to take advantage of your body clock.</s>DR. SANJAY GUPTA, CNN CORRESPONDENT (voice-over): For many people, morning workouts are like a cup of coffee -- they stimulate and get the day going strong. But for all the advantages, morning workouts could also cause...</s>DR. PHYLLIS ZEE, NEUROLOGIST, NORTHWESTERN UNIVERSITY: Injury, fatigue, you know, tearing in your muscles.</s>GUPTA: Dr. Zee studies circadian rhythms, which are the body's own daily rhythms, controlled by the brain.</s>ZEE: The best time to work out is probably in the late afternoon. And the reason for that is that your muscle strength is at its peak, it's at its highest.</s>GUPTA: Circadian rhythms, she says, control the body's internal time clock. They also control body temperature, which can be one to two degrees warmer in the afternoon when she says muscles are more supple and the risk of injury dips. Dr. Sanjay Gupta, CNN, reporting.
What is Best Time to Workout?