Jet lag is one of the most common problems confronting the world traveler, and our mission volunteers are certainly not immune. Though not life threatening, this disturbance of the sleep cycle can seriously interfere with our ability to function at full capacity. We often need to hit the ground running, take on major responsibility, make critical decisions and work long hours under difficult conditions. We do not usually have the luxury of spending several days recuperating from a jet lag caused hangover, so it becomes important to consider the cause and possible ways to lessen its severity.Jet lag is a sleep disorder that results from crossing time zones too rapidly for our circadian clock to keep pace. This clock, located in the brain’s hypothalamus, regulates alertness during the day, and sleepiness at night, in response to alternating patterns of light and dark In addition to setting time for sleeping and waking, circadian rhythms also dictate times for eating and some hormone regulation. Of interest, the severity of jet lag is not related to the length of the flight, but to the number of time zones crossed. It is also worse when traveling from the West to the East than in the reverse direction. If traveling in a North South direction, you may get tired and sleep deprived, but do not get jet lag. Some of the symptoms resulting from jet lag can be insomnia, sleepiness during the day, dysphoria, and most importantly, diminished physical performance and even cognitive impairment. There is a wide person-to-person variation in severity and specific type of effect following a given disturbance of the light dark cycle.
Many treatment strategies have been recommended for jet lag, some with more evidence of effectiveness than others. A recent review (1), recommends three approaches:
1. Promoting a realignment of the body’s circadian clock by using an appropriately timed exposure to light and the administration of melatonin,
2. Planning an optimal timing and duration of sleep
3. Using medication to counteract the symptoms of insomnia and/or daytime sleepiness.
You can readjust your circadian clock by exposing yourself to bright sunlight or strong artificial light, in the morning after eastward travel and in the afternoon after traveling to the west. Also plan to stay in the dark or in subdued light for the first few hours of daylight after long eastward fights or a few hours in the afternoon after long flights heading west. Two or three days of such a regimen should be sufficient.
Melatonin is a hormone secreted by the body during nighttime hours that has an effect on circadian rhythm opposite to that of sunlight. The ideal dose and timing of administration have not been clearly established, but it is commonly taken in a dose of 0.5 to 3mg at bedtime after arrival at your destination. It is available as a nutritional supplement in a 3mg tablet.
Plan a strategic sleep schedule prior to the trip, gradually shifting by 1-2 hour increments toward matching the projected schedule at your destination.. Flying first or business class usually means more restful sleep, as does eating sparingly and avoiding alcohol. Hypnotic agents can be used to counteract insomnia caused by jet lag. Short acting agents such as Ambien or Lunesta in modest doses are recommended to avoid next day sleepiness. The use of such agents during actual travel may be more problematic, unless the flight is of very long duration. Caffeine in moderate amounts may be useful to counteract daytime sleepiness, but taken late in the day may interfere with sleep. A relatively new agent, Nuvigil (Armodafinil), has been used to promote wakefulness in patients with narcolepsy and other conditions that cause daytime sleepiness. It is not currently FDA approved for use with jet lag, but showed promise in a recent study to promote wakefulness in patients with day sleepiness associated with jet lag.
In his review (1), Sack points out that much more research is needed to more completely uncover the causes of jet lag, and to determine the most effective treatment measures. I recommend reading this article if you want to learn more about this fascinating and troubling condition.
(!) Sack, R.L. Jet Lag: NEJM 2010;362; 440-47.
Roger Boe MD