Syndrome Jet Lag is the clock-mediated persistence of the internal timing of wake and sleep tendencies, now at odds with new local time that produces insomnia by night and daytime hypersomnolence. The symptoms usually persist for 2-14 days depending on the number of time zone crossed and the direction of travel. For westward travel, the circadian clock can be shifted with preferential evening light exposure. Conversely, morning light exposure will facilitate adjustment to earlier hours after eastward travel. Short acting sedative hypnotic medications at new bedtime.
Effects are generally small.
The requirement of alertness and optimal performance by night and sleep during the day is at odds with natural tendency. Even with a limited exposure to daylight, the circadian clocks of shift workers remain fixed in a normal diurnal variation with the peak of alertness in the early evening and the trough in the early morning. The cumulative effects of repeated night shift exposure result in chronic sleep restriction and partial sleep deprivation. Treatment Shift work schedules should be individualized for each workplace. Empiric data suggest that forward rotating shifts are generally better tolerated.