Jet lag happens when traveling across several time zones. Our internal body clock is known as the circadian rhythm and tells us when we should sleep and when we should be awake. This is set at your original time zone, and it doesn’t change automatically to the new time zone. The more time zones that are crossed, the more likely you are to feel jet-lagged. However, with some preparation before a long-haul trip, you can help to adjust to a new time zone and feel the effects of jet lag less.