Jet lag
Jet lag can have several symptoms. It usually takes the form of fatigue and insomnia. Also, headache, depression, even nausea may strike people. Sufferers can use caffeine or sleeping pills as a way of treatment. Using caffeine (such as in tea or coffee) is helpful, either in the morning when going westward or in the afternoon when going eastward. The hormone melatonin is said to help people sleep. Also, doing things like changing sleeping patterns several days before departure may help people adjust to the new time zone.