People who travel long distances east or west often suffer grogginess and disorientation resulting from the body’s internal clock being out of synch with the sun. The body’s circadian clock is slightly longer than 24 hours but is synchronized by various environmental factors, the most important of which is light exposure. Jet-lag occurs when the intrinsic clock cannot adjust fast enough.
Westward travel is easier since it require setting the internal clock later rather than earlier. The more time zones that are crossed, the longer lasting and more severe are the symptoms. We can move our internal clock later by 2 hours per day, but can move it earlier by only 1 or1 ½ hours. Light exposure is of primary importance in shifting the circadian clock.
The core body temperature drops 2 to 3 hours before the usual time of awakening. Exposure to bright light before this minimum will set the internal clock later; exposure to bright light after the temperature minimum sets the clock earlier. People who frequently shift time zones may do better if they remain on their home-based schedule.
Sleeping pills may be helpful in reducing jet-lag insomnia but don’t reduce daytime grogginess. Adverse effects are frequent and may include nausea, vomiting and confusion. People who take caffeine are less sleepy but have more nocturnal sleep complaints. Circadian rhythms are retrained more quickly in people who use daytime caffeine.
Jet lag can be minimized by a good sleep environment as well as strategic avoidance and exposure to light. If feasible, remaining on the home-based scheduled will minimize symptoms.
For information on a Jet Lag Plan