Jet lag: what is it, symptoms, prevention

Many of us dream about traveling the world. Maybe you’d love to see the Northern Lights, take a photo in front of the Eiffel Tower, go surfing in Hawaii, or taste authentic Thai cuisine. No matter which destinations are on your bucket list, it’s likely that traveling there will involve a few days of feeling “off” and sleepy due to jet lag.

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Jet lag, also called desynchronosis, happens because your body’s internal clock (known as circadian rhythm) has trouble adjusting when you travel across multiple time zones (Ambesh, 2018). Jet lag is not just a pesky inconvenience; it’s technically classified as a (temporary) sleep disorder (Sack, 2007).

Jet lag is a group of symptoms that occur in the days after air travel across multiple time zones. They tend to be more severe when you travel eastward compared to westward, especially the day after you arrive at your destination (Basit, 2021). 

Jet lag symptoms may include (Roach, 2019; Schwab, 2020; Fowler, 2017): 

• Headache

• Irritability

• Mood changes

• Daytime sleepiness

• Trouble falling asleep

• Waking up during the night

• Generally not feeling well

• Stomach problems such as nausea and constipation

• Trouble concentrating or performing tasks

• Reduced motivation

• Decreased physical or athletic performance

Some people, such as business executives and airline crew, frequently travel internationally. This can cause the symptoms of jet lag, such as fatigue (lack of energy), to persist long-term, and may increase the risk of developing depression, heart disease, digestion problems, and other medical conditions (Schwab, 2020; Choy, 2011).

Our bodies follow an internal, 24-hour clock known as circadian rhythm. The human body relies on this internal clock to perform certain biological functions, like releasing melatonin (a hormone that helps you sleep) and regulating body temperature (Basit, 2021). Exposure to cycles of light and darkness affects our circadian rhythm. Dim light causes an increase in melatonin release about two hours before your usual bedtime (Ambesh, 2018).

Jet lag occurs because your natural circadian clock lags behind the rapid transition across multiple time zones made possible by modern air travel. It results in a disconnect between the local time and your body clock (Ambesh, 2018).

Older adults, especially those ages 60 years and older, may have more trouble recovering from jet lag. This is likely due to reduced melatonin production and circadian rhythm irregularities that occur with age (Lee, 2017). 

After a few days, your body clock usually adjusts to the new time zone without specific treatment. How long until you’ll feel adjusted? It depends on your direction of travel and the number of time zones you’ve traversed in your long-haul flight (Ambesh, 2018). In general, your body will adapt to the new schedule as follows:

• When you travel from west to east, your body can naturally adjust to one time zone change per day.

• When you travel from east to west, your body can naturally adjust to 1.5 time zone changes per day.

For example, suppose you’re flying westward, from London to New York City. Since you’ll cross five time zones on this trip, your body will likely need 3 to 4 days to adapt to your destination’s time zone. 

The American Academy of Sleep Medicine (AASM) recommends using light exposure and melatonin to help overcome the effects of jet lag. With light exposure, you intentionally spend time in natural sunlight upon arrival in your new time zone, if possible. For example, after you drop off your suitcase at your hotel, you might consider going for a long outdoor walk to explore the area. Sunlight exposure and physical exercise can help to reset your body’s internal clock (Choy, 2011).

In a sense, these cues can help to “trick” your body into thinking that it’s time to be awake, even though you’d be asleep if you were home.

Supplements and medications

Also, taking an over-the-counter melatonin supplement an hour before bedtime for three days after arrival may help you overcome the symptoms of jet lag sooner (Lee, 2017). Taking melatonin can also help you fall asleep at bedtime that’s appropriate for the local time. There’s no standard dosage for melatonin, but the usual dosage range is 0.5 mg to 5 mg taken one hour before bedtime (Shane-McWhorter, 2020). 

Some medications are sometimes prescribed “off-label” by a healthcare provider to help relieve jet lag symptoms (Arendt, 2018). A few examples include:

• Benzodiazepines, such as lorazepam (Ativan), can be taken as needed to help with trouble sleeping due to jet lag.

• Sedatives, such as zolpidem (Ambien), may help overcome temporary insomnia caused by jet lag.

• Stimulants, such as modafinil (Provigil), may help improve daytime sleepiness due to jet lag. 

However, these are powerful prescription drugs. They carry risks of drug dependence and serious side effects, especially if they’re taken with certain pain medications or alcohol. Although limited quantities of these drugs could help relieve short-term jet lag symptoms, they’re not commonly prescribed for jet lag. 

Safer options include the above-mentioned melatonin supplements, exposure to bright light to help reset your internal circadian rhythm, naturally adjusting with time, along with some mitigation strategies.

You can take steps to minimize or reduce jet lag, but it’s usually impossible to completely prevent jet lag. This is especially true when you’re long-hauling across multiple time zones within a day’s travel.

One strategy is to start changing your sleep schedule in advance of a trip. Taking melatonin before bedtime may help you adjust your sleep-wake schedule in preparation for travel. It’s recommended to take melatonin to help you fall asleep closer to the target bedtime of your destination at least two days before departure. This strategy is much safer than taking prescription medications, especially for older adults (Lee, 2017). 

However, this strategy isn’t usually helpful for very short trips or people who constantly travel, such as airline crew (Choy, 2011). Instead, for these situations, it may make more sense to keep your body on your usual bedtime schedule, minimizing the interruption to your body’s circadian rhythm and reducing the effects of jet lag. 

Losing sleep while traveling can make jet lag symptoms worse. If you can, book an airline ticket for a seat that allows you to recline fully. This may help you get more sleep during your flight (Ambesh, 2018). It may also help to use an eye mask to help block out bright light while in-flight.

Dehydration can make the effects of jet lag worse. You can prevent dehydration by drinking plenty of water while you’re traveling. This is also helpful to prevent constipation, which is common among travelers. While caffeine may seem to help you beat travel fatigue temporarily, it can lead to poor sleep quality (Ambesh, 2018). 

According to the Sleep Foundation, it’s best to resist the temptation to take a long nap while you’re trying to overcome jet lag. Instead, try to limit naps to 30 minutes and avoid them completely in the eight hours before your planned bedtime.

There’s nothing that will help you completely prevent the symptoms of jet lag, but with an intentional approach, you can overcome it more comfortably. You can limit the effects of jet lag by upgrading to a seat that reclines to help you get more sleep during your long-haul flight, drinking plenty of water while traveling, and staying away from alcohol and caffeine until you’ve adjusted to your new time zone.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

June 21, 2021

Written by

Patricia Weiser, PharmD

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.