What do you feel when you have jet lag?
Though jet lag is temporary, it could significantly affect the quality of your vacation or the comfort and overall outcome of your business travel. And symptoms vary – either you experience only a few or most of these symptoms:
· Sleepiness during the day and insomnia (difficulty falling asleep and staying asleep)
· Daytime fatigue
· Unwell feeling
· Difficulty staying alert and focused
· Stomach problems, constipation or diarrhea
· Body aches
· Menstrual symptoms in women
What happens in jet lag?
Jet lag results from crossing time zones in too short a time, too fast for the body clock to keep pace.
Our body has a 24-hour internal clock that directs our circadian rhythm. The circadian rhythm is a synchrony of our body processes (heartbeat, temperature, sleep, hormonal balance, etc.) and the sleep-wake cycle. Our body organs have their own molecular clocks, regulated by the circadian clock control center located in the hypothalamus of the brain. The circadian clock is synchronized to the sun’s light-dark cycle. When it’s day, the clock makes the body alert; when it’s night, it induces sleepiness.
The clock is slow to reset, so that a sudden change in time zone disrupts the usual light-dark body schedule. The misalignment between the circadian clock and local time puts body processes and social activities out of sync, causing body malaise.
What can I do to avoid jet lag?
Jet lag can be aggravated by travel fatigue (not associated with crossing of time zones) due to prolonged immobility, cramped space, tension and irregular sleep times. But this kind of fatigue disappears in a day or two with adequate rest, diet and sleep. Symptoms of jet lag, however, persist until the circadian rhythm is attuned to the local time.
A clinical practice article published in The New England Journal of Medicine listed treatment strategies that coincide with the guidelines issued by the American Academy of Sleep Medicine:
Timed exposure to light. The timing of exposure to light is the most important time cue for resetting the body clock. Light regulates the sleep-wake cycle. The natural light from the sun facilitates the adaptation of the circadian clock to the local time. But it is useful to avoid light when exposure would impede adaptation. Seeking out bright light at optimal times of the day would hasten resynchronization.
For travel across up to eight time zones, seek bright light in the morning after eastward travel and in the evening after westward travel. Exposure to light in the morning shifts the clock to an earlier time, and exposure to light in the evening shifts the clock to a later time.
After crossing more than eight time zones during eastward travel, avoid bright light for the first two to three hours after dawn; starting on the third day, seek bright light in the morning. During westward travel, avoid bright light for two to three hours before dusk in the first two days after arrival. On the third day, seek exposure to bright light in the evening. This strategy is based on the theory that after a person crosses eight or more time zones, the circadian rhythm may misinterpret “dawn” as “dusk” or vice versa.
Sleep in a room with drawn blinds or dark curtains. If avoiding bright light is not feasible, wearing dark, antiglare sunglasses may be an alternative. For an indoor business traveler who is away from natural sunlight in the new time zone, an artificial bright light, such as a table or desk lamp, may simulate daylight.
The circadian system will have shifted in a few days so that light avoidance can be discontinued.
Melatonin intake. The pineal gland in the brain releases the sleep-inducing hormone melatonin for about 10 to 12 hours at night. When melatonin is taken in the evening before the body naturally releases its melatonin, it resets the body clock to an earlier time. When it is taken in the morning after secretion levels have fallen, it resets the clock to a later time.
The administration of melatonin as a sleep aid for jet lag has been extensively studied and it is now a standard treatment for jet lag disorder. Small doses at 0.5 mg to be taken 20 minutes before going to bed are the recommended doses. At higher doses, it is shown to be more hypnotic or sleep-promoting. However, whether it is a 0.5-mg dose or a 5-mg dose, the efficacy of the two doses is similar.
Scheduling of sleep times. It is not the shifting of sleep times that resets the clock; it is the fact that people sleep in the dark with their eyes closed so that exposure to light is limited.
The retina — the tissue lining at the back of the eye — detects light and transmits the light signals to the hypothalamus of the brain, which is connected to the melatonin-producing pineal gland.
Before leaving on eastward travel, go to sleep one hour earlier each night for a few nights. And if you are flying west, try going to bed one hour later for several nights. Adjusting sleep times by one or two hours approximating the destination time will shorten jet lag.
It will help sleeping in flight if it’s nighttime at your destination. Use earplugs and an eye mask to block out noise and light. Try to ward off sleep if it’s daytime where you are heading.
It takes about a day to recover for each time zone crossed; if possible, try to arrive a few days ahead of the scheduled meeting or conference.
Medications. The use of 10 mg zolpidem at bedtime for three to four nights after eastward travel across five to nine time zones have been found to improve sleep times. Short-acting zaleplon also promotes sleep during an overnight flight.
Although side effects are uncommon, it is advised that test doses be taken at home before using them during travel. Side effects may include nausea, vomiting, confusion and morning sleepiness. And they may not help with daytime symptoms of jet lag. Sleep-inducing medication during air travel may also increase the risk of deep vein thrombosis (formation of blood clot in the vein due to prolonged immobility).