Jet Lag (cont.)
John P. Cunha, DO, FACOEP
John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
In this Article
- What is jet lag?
- What are other symptoms and signs of jet lag?
- What is a time zone?
- What causes jet lag?
- How does the body keep time?
- What is the role of melatonin in jet lag?
- Does the direction of travel matter?
- Do the symptoms of jet lag vary in intensity?
- What are risk factors for jet lag?
- How long does jet lag last?
- Should people take melatonin for jet lag?
- Are there any remedies for jet lag? Is it possible to prevent jet lag?
What are risk factors for jet lag?
The main cause of jet lag is travel across different time zones. However, there are certain risk factors that may result in symptoms being more severe or longer-lasting.
- Travel across three or more time zones: Most people can adjust rapidly to a one or two time zone change. Three or more may cause more noticeable symptoms of jet lag.
- Flying east: As stated previously, travel from west to east causes travelers to "lose" time, and this can be a more difficult adjustment.
- Age: Older adults may recover from jet lag more slowly.
- Frequent travel: Pilots, flight attendants, and frequent business travelers who are constantly in different time zones may have difficulty adjusting.
- Preexisting conditions: Preexisting sleep deprivation, stress, and poor sleep habits prior to travel can exacerbate jet lag symptoms.
- Flight conditions: The monotony of travel, immobility and cramped seating, airline food, altitude, and cabin pressure can impact jet lag symptoms.
- Alcohol use: Overconsumption of alcohol during long flights can also worsen the symptoms of jet lag.
How long does jet lag last?
Recovering from jet lag depends on the number of time zones crossed while traveling. In general, the body will adjust to the new time zone at the rate of one or two time zones per day. For example, if you crossed six time zones, the body will typically adjust to this time change in three to five days.
Jet lag is temporary, so the prognosis is excellent and most people will recover within a few days.
Complications of jet lag are extremely rare. If a person has a preexisting heart condition, the stress of the disruption in the circadian rhythm, combined with the stress of travel, the high altitude, and immobility during flight may result in a heart attack. If the jet lag results in chronic sleep deprivation, stroke may occur in certain predisposed individuals.
Should people take melatonin for jet lag?
Another option is synthetic melatonin, which is classified in the U.S. as a dietary supplement. A study in the British Medical Journal in 1989 reported that taking synthetic melatonin tablets can help travelers restore normal sleeping patterns. In that study, 20 volunteers traveling back and forth between New Zealand and England took daily doses of either 5 mg of melatonin or a placebo (a blank, or sugar pill) before, during, and after their flights. Those taking melatonin returned to their normal sleep patterns in 2.85 days on average compared with 4.15 days for those taking a placebo.
However, scientists in the U.S. and many other countries are not yet convinced that enough evidence exists to prove the efficacy of over-the-counter (OTC) melatonin tablets. These scientists also point out the following:
- No information has been compiled on the long-term effects of taking melatonin.
- No watchdog measures are in place to assure that all OTC melatonin products meet minimum standards.
In 2005, MIT released the results of a meta-analysis of 17 peer-reviewed studies using melatonin. It showed that melatonin was effective in helping people fall asleep at doses of 0.3 mg. Larger doses of melatonin seem to be less effective after only a few days' use.
For the purpose of treating jet lag, it is suggested that a dose between 0.3 mg-5 mg of melatonin be taken on the first day you travel at the time you will want to go to sleep at your destination. This may be continued at bedtime for a few days once you are at your destination. Melatonin seems to be most effective when crossing five or more time zones, or traveling east. Only adults should take melatonin. Do not drink alcohol when taking melatonin.
Be aware that higher doses of melatonin can cause sleepiness, lethargy, confusion, and decreased mental sharpness. Operating motor vehicles or heavy machinery should be avoided after taking your daily dose of melatonin. Consult a doctor if planning on taking melatonin.
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