Phase delays, when travelling westward, call for light in the evening or melatonin in the morning. Studies by Dr. Lewy, who pioneered research into seasonal affective disorder, indicate that melatonin doses as low as 0.5 mg taken in the morning or afternoon caused greater phase shifts in the correct direction and were more effective at eliminating the symptoms of jet lag than a 5 mg bedtime dose. Unless you pre-treat yourself for several days and set yourself up for the new time zone, you won't be able to eliminate it. So if you travel three time zones, you only have jet lag for one day. Jet lag symptoms include poor sleep quality, daytime fatigue, and impaired concentration and alertness.
Severity varies by age, rhythm stability and the number of time zones crossed.
Eating meals when an endogenous clock is out of whack has been associated with raised triglyceride levels, which can be a risk factor for coronary heart disease. You need to get that clock shifted to the new time zone as quickly as you can. The three main pharmacological treatments for jet lag include psychostimulants to increase alertness, chronobiotics to ease time zone adjustment and hypnotics for sleep promotion. Choosing a treatment depends on the length and purpose of a trip. Subjects in the melatonin group experienced a significantly reduced sleep latency as reported in their sleep logs, said Dr. Suhner, who further noted that many over the counter formulations of melatonin have been shown to be of questionable quality and purity.