Managing Jet Lag
Jet lag can be better managed with behavioral techniques.
Posted Nov 16, 2009
In general, it takes about 1 day to acclimate to each time zone crossed. Some laboratory studies suggest that bright light can help shift the circadian rhythm by as much as 2 to 3 hours per day, potentially speeding up recovery from jet lag. Crossing one or two zones usually does not result in major symptoms. Crossing three time zones is usually enough to cause significant symptoms. These symptoms may last a few days to more than a week. Traveling around the world can result in significant symptoms that persist for weeks. Of note, it also appears that it is more difficult to adapt to jet lag as we get older. Shift workers also tend to have a more difficult time with jet lag.
The main thing to keep in mind is that travel across time zones forces "phase shifts" in the circadian rhythm. Eastbound flights force a phase advance. This means that you will have to go to bed at an earlier circadian time to match the clock time in the new time zone. For example, if you travel east over 3 time zones your usual bed time of 10:00 PM now falls at a circadian time of 7:00 PM so that it will be difficult to fall asleep. In the same way, a local clock time of 7:00 AM is the circadian time of 4:00 AM so that it will be difficult to wake up and be alert. Westward travel tends to be less difficult than eastward travel as it is easier to stay up later than go to sleep earlier. In this case 10:00 PM local time falls at a circadian time of 1:00 AM and 7:00 AM clock time is the circadian time of 10:00 AM. An eastbound flight forces a phase advance with sleep onset problems and daytime fatigue while westbound flights force a phase delay with fatigue and sleepiness.
There are two useful approaches to reducing the severity and duration of jet lag symptoms. There are preventative strategies carried out before travel to help prepare for and so reduce the impact of jet lag. There are also ameliorative strategies to cope with and reduce the effects of jet lag. Both of these involve behavioral strategies, use of photo therapy, and possibly melatonin. The recommendations below are best for trips across three to six time zones. Travel over more than six time zones is more complicated when using phototherapy and melatonin. In this situation, unless very carefully timed, light therapy or melatonin could actually make jet lag worse rather than helping. It is probably best to consult a sleep specialist to help you work out the more complex schedule of use needed for these kinds of trips.
You may have encountered very complex schedules for the use of bright light and melatonin but people often find these too complicated to actually use. The techniques described below are relatively simple and generally easier to use.
Short duration trips involving travel across three or more time zones may not give enough time to significantly recover from the time shift before the return trip. In this case, it is probably best to try to maintain your regular sleep/wake schedule to the degree possible and plan meetings and activities at times that you will be most alert.
Preventative behavioral strategies involve beginning to shift the internal clock by changing the sleep schedule before travel. For eastward travel this would involve going to bed earlier and getting up earlier for a week before travel. Important meetings or vacation activities should be scheduled in the afternoon in the eastern time zone. Another strategy is to arrive several days before important activities to give time to acclimate to the new time zone. Westward travelers can benefit by beginning to gradually go to bed later and get up later during the week before travel.
It is important to decrease the effect of travel itself on jet lag. Many of the uncomfortable aspects of jet lag occur due to the stress of travel which can also affect the circadian system. Drinking a good deal of water can help as dehydration actually makes it more difficult for the body temperature adjust to the new time zone, making falling asleep more difficult. Avoidance of caffeine and alcohol on the trip will help prevent dehydration.
Sleeping medications do not shift the circadian clock, however, they can sometimes be helpful in adjusting to the new bed time. They may help improve sleep and reduce some symptoms of jet lag. Caffeine has often been used to promote daytime alertness when dealing with the typical decreased alertness characteristic of jet lag.
Unless you are staying for a very brief time in the new time zone, as described above, or are able to control your schedule so that you can use bright light effectively, it is best to try to adjust to the new time schedule even if your body does not agree. Exposure to the local sun light, meal and activity schedule will tend to resynchronize the circadian rhythm to the local time.
With regard to phototherapy, after traveling east, the recommendation is for exposure to morning sun light and decreased light in the evening hours. This will tend to advance the sleep schedule so that you will want to go to sleep earlier. For westward travel, evening light exposure may help by making it easier to stay up until the new bed time. Some frequent flyers may want to purchase light boxes and these can be used prior to travel to help prepare for the trip. The light boxes can be used several days before travel. If going east, you should use bright light in the morning and if going west, use it in the evening. Be sure to pay attention to all health warnings associated with the use of light boxes such as the safe amount of eye exposure, being sure that the box has proper shielding for ultraviolet wavelengths and not using it unless under the supervision of your physician if you have a history of mania.
There is some evidence that melatonin both helps shift the circadian clock and helps consolidate sleep. When traveling east, melatonin 0.5 mg can be taken in the evening to help advance the circadian clock. I do need to point out, however, that melatonin has not yet been shown to be fully safe and effective and no FDA approved indication currently exists for it.
Jet lag is a feature of the modern world that affects many people. Use of a few behavioral techniques can help assure that you don't end up sleepless, in say, Seattle.