July 19, 2018
Canceled flight

Jet Lag: Causes and Treatments

by Berkeley Wellness  

All of us have an internal body clock tuned to the 24-hour daily cycle. Located in the brain’s hypothalamus, this “clock” tells us when to wake up and when to sleep. When something disrupts our natural daily rhythm, we tend to feel tired and out of sorts. Travelers experience this as jet lag, which occurs when they fly across time zones and their bodies don’t have time to adapt properly. Jet lag can cause extreme fatigue, daytime drowsiness, irritability, headaches, and gastrointestinal upset, as well as decreased mental alertness and strength.

Westward journeys are less stressful than eastward—it’s easier for a person’s biological clock to set itself back than forward. Thus, adding a couple of hours to the day may not disrupt sleep patterns, but losing a couple of hours almost always does. Flying north to south has no effect.

Though many sleep researchers are studying jet lag, the problem remains hard to prevent and hard to treat. Time is the only certain remedy.

Still, several strategies can help minimize the sluggishness and disorientation that follow a long flight:

  • If you’re flying eastward across several time zones, try to arrive in the late evening, so you can go to bed shortly afterwards and wake up at a reasonable hour the next day. Unfortunately, most eastbound transatlantic flights depart in the early evening and land in the morning, completely confusing a traveler’s body clock.
  • Try to reset your internal clock before the trip. You might go to bed and get up an hour earlier each day for three days before a long eastward flight. For a westward trip, go to bed and get up an hour later each day. Of course, not everybody can change sleep time so easily.
  • During an overnight flight, try to fall asleep soon after you board. A sleep mask and earplugs or noise-cancelling headphones can help.
  • Drink enough fluids (not alcohol); dehydration can aggravate jet lag.
  • Adjust to the new time zone as quickly as possible. Set your watch to the new time zone while you’re in the air. If you arrive at breakfast time, eat breakfast. Get out and walk around. That first night, force yourself to stay up until a reasonable hour.
  • Expose yourself to the sun or other bright light after arrival. Timing your exposure to bright light can help reset your body clock and ease symptoms. If you fly eastward through several time zones, get plenty of light in the morning. For those flying west, seek ample light in the evening—outside if it’s bright enough or indoors in a bright in­terior. Some veteran travelers bring along a small device that simulates natural light.

Mellow out with melatonin?

Produced by the brain’s pineal gland at night, this hormone plays a key role in regulating sleep/wake cycles. Because of this, many people have touted the benefits of melatonin supplements to ward off jet lag. Indeed, some studies suggest that melatonin supplements do accelerate the body’s adjustment to a new time zone—but only when taken at the right dose, at the right time of day, and after arrival.

The last time the Cochrane Collaboration reviewed the scientific literature on the topic, it found that 8 out of 10 melatonin studies had positive results. It concluded that the supplement “is remarkably effective in preventing or reducing jet lag” when traveling across five or more time zones, especially eastward. Its usefulness for westward travel or over fewer time zones is unclear; taking it before travel does not help prevent jet lag.

What’s the right dose? Keep it low. Low doses may be as effective as higher ones for many jet lag symptoms, though higher doses promote sleep more. In an article in the New England Journal of Medicine in 2010, a leading sleep researcher recommended, for eastward travel, ½ to 3 milligrams at bedtime after arrival, until you get used to local time. Westward travelers who wake up too early in the morning because of jet lag may benefit from taking just ½ milligram of melatonin when they awaken. For short stays lasting only a day or two, melatonin probably won’t help, since it takes a few days for it to affect the body clock.

Side effects are rare, but there have been reports of melatonin causing depression, dizziness, headache, and nausea. It can also cause sleepiness the next day, though less than sleeping pills. The safety of long-term daily use is not known.

Don't count on diet

Some travelers claim that eating a special pre-trip diet helps them avoid jet lag. One popular example, the Argonne Anti-Jet-Lag Diet, emphasizes alternating feasts of heavy, high-protein foods (such as steak, eggs, and burgers) with near fasts of liquids, fruits, and salads. Research on these diets is skimpy, however, with little or no evidence that specific foods can reduce jet lag or its symptoms.

Rx options

If you want a prescription sleeping pill to take during the flight or after arrival (to help reset your body clock), talk to your doctor about the pros and cons of various options. To combat daytime drowsiness, some travelers take the prescription stimulants modafinil (Provigil) or armodafinil (Nuvigil), which are approved to treat narcolepsy, apnea, and circadian disruptions caused by shift work. The FDA has not approved these drugs for jet lag, but they may help some people, even in small doses.

Originally published May 2016. Updated March 2017.