On long journeys travellers can reduce the effects of jet lag by choosing when to fly. If possible, you should fly at night and sleep for the whole journey. Make sure you feel tired before the flight. Change your watch when the flight takes off. If necessary, take a sleeping tablet, but don't take a strong one, and don't drink alcohol during the flight. Make sure the flight attendants don't disturb you. When you arrive, don't have a rest. You should do some light exercise or go out in the sunlight. Make sure you stay awake until night-time.