Exercise can shift the human body clock, with the direction and amount of this effect depending on the time of day or night in which people exercise. That’s according to new research in published in The Journal of Physiology. These findings suggest exercise could counter the effects of jet lag, shift work, and other disruptions to the body’s internal clock (e.g. military deployments) helping individuals adjust to shifted schedules. The circadian “body”’ clock is the 24-hour cycle that regulates many physiological processes including sleeping and eating. Many factors affect this internal body clock including light and time cues. Exercise has been known to cause shifts in the circadian clock however very little is known about this effect. This study found that exercising at 7 am or between 1 and 4 pm advanced the body clock to an earlier time, and exercising between 7 and10 pm delayed the body clock to a later time. Exercising between 1 and 4 am and at 10 am, however, had little effect on the body clock, and the phase-shifting effects of exercise did not differ based on age nor gender. The researchers at University of California, San Diego and Arizona State University examined body clocks following exercise in 101 participants for up to five and a half days.