Circadian rhythms, jet lag, and chronobiotics: an overview.

This overview considers the origins of jet lag in terms of altered circadian rhythmicity. The properties required of a chronobiotic--an agent to cause phase adjustment of the body clock--are discussed, and an account is given of the major candidates at the present time: light, melatonin, activity, and benzodiazepines. It is concluded that current knowledge indicates that a combination of factors is likely to be most effective.