International travel is exciting, but crossing multiple time zones can often leave travelers feeling out of sync with local time. This phenomenon, known as jet lag, occurs when the body's internal clock, or circadian rhythm, is disrupted. Symptoms of jet lag include fatigue, difficulty sleeping, and trouble concentrating. Fortunately, there are several ways to minimize the effects of jet lag, and one strategy is particularly effective. By adjusting this key factor, travelers can help their bodies acclimate more quickly to the new time zone.