Jet Lag Explained: Causes, Symptoms, And Treatments

If you've traveled by air across the country or across the globe, you've likely experienced jet lag. Crossing several time zones in a short period of time disrupts your internal body clock, which can cause a host of uncomfortable symptoms. These may include fatigue, insomnia, mood changes, and digestive upset (via Sleep Foundation). As if long-distance travel isn't uncomfortable and exhausting enough.

Occasional jet lag isn't serious, but it can affect how you feel, and it can make the first few days of your trip less enjoyable. If you're traveling for work or competition, it can also affect your performance. If you're a frequent long-distance traveler, some research has shown that chronic jet lag could have long-term health consequences (via Aging). 

There isn't a cure for jet lag (via Cleveland Clinic). Like the common cold, you just have to wait it out. But there are things you can do to help speed up your body's adjustment to a new time zone. There are also steps you can take pre-travel to minimize jet lag's effects. 

Time difference is the main cause of jet lag (via Sleep Foundation), but there are other contributing factors. Individual physiology and how sensitive your body is to change can influence how you experience jet lag (via Circadian Rhythm). The time of day at which you make your voyage can also make a difference. If you take an overnight flight and you're not able to sleep well on the plane, you're going to feel much worse when you arrive at your destination in bright sunlight the next morning (via The Washington Post).

According to an article in Sleep Medicine Clinics, jet lag tends to worsen with age. The body becomes less "phase-tolerant," and older people will suffer more from circadian misalignment than younger people. In addition, the amount and quality of sleep you had before your trip can make jet lag better or worse. If you were already in a sleep debt, or you were getting poor-quality sleep, jet lag's likely going to have a bigger impact. 

Several other things can contribute to jet lag, including extended periods sitting on a plane, low oxygen and air pressure in the cabin, and dehydration from the typically dry, warm air circulating inside airplanes (via Cleveland Clinic).

Just as there isn't any one-size-fits-all answer to what symptoms you can expect or how they will affect you, there's also no single answer to how long jet lag will last. It depends on a variety of factors, including what you do in the days leading up to travel and once you get off the plane. It could be a few days to a few weeks. The general guideline, however, is that the farther you travel, the longer jet lag will stick around. This makes sense since the more time zones you cross, the more your sleep schedule is impacted. According to the Mayo Clinic, it typically takes one day per time zone crossed to recover. So if you've crossed seven time zones, you can expect to be feeling better within a week. 

Jet lag may subside faster if you travel from west to east, according to a 2011 research review in Pharmacy and Therapeutics. Jet lag from eastward travel, in which you lose hours of the day, typically lasts longer than jet lag from westward travel, in which you gain hours. 

Unfortunately there's no cure for jet lag, and it's nearly inevitable that you will suffer some symptoms with long-distance travel. But there are some tried-and-true methods to help alleviate some of your suffering. The Cleveland Clinic suggests adopting the sleep-wake schedule at your destination as soon as possible. Although it may be tempting to stay in bed until 1 p.m. the day after your arrival, it will be better for you in the long run if you wake up earlier. 

To avoid gastrointestinal upset, eat smaller meals and avoid new foods for the first couple of days. This will alleviate stress on your digestive system. You should also avoid alcohol. While it might be customary to have a cocktail or two on when you're on vacay, it's going to make matters much worse. According to a 2015 research review in Alcoholism, Clinical and Experimental Research, any amount of alcohol can reduce sleep quality by disrupting the later stages of sleep, which can cause you to wake up earlier than planned. Likewise, while caffeine can help you feel alert first thing in the morning, avoid it for at least six hours before bedtime (via Sleep Foundation). 

The Centers for Disease Control and Prevention (CDC) says that if you are tired during the day you can take short naps to help you feel better. However, keep them to 20 minutes, because naps that are too long can make it harder for you to fall asleep at bedtime. 

Sunlight has a significant effect on your internal clock by helping to regulate melatonin production (via Mayo Clinic). Cells in the retina of the eye send signals to your brain to reduce melatonin production when exposed to bright light. At night or in low light, those cells send signals to the brain to increase melatonin production. You can use sun exposure strategically to help get your sleep schedule back on track. If you've traveled eastward, getting some sun first thing in the morning will signal to your body that it's time to be awake and alert; if you've traveled westward, exposing yourself to sunlight later in the afternoon tells your body it's not time for bed yet. If you don't have access to daylight, you can use artificial light from a bright lamp or from a light box. 

In a 2016 study by Stanford University School of Medicine, researchers found that pre-voyage light therapy could be used to prevent or lessen jet lag. Instead of daylight exposure, however, they discovered that light exposure during sleep was most effective because circadian rhythms have increased sensitivity to light during the night. This is true even when the eyelids are closed. They also found that short flashes of light were more effective than continuous light therapy for resetting the internal clock. This helped study participants to adjust more quickly to a new time zone, and subsequently feel less jet-lagged. 

Jet lag symptoms, including fatigue and nausea, can also be symptoms of viral infections, such as the flu (via Medical News Today). So, the general feeling of malaise in the first few days after your flight can feel like the onset of an illness. But jet lag symptoms should dissipate relatively quickly (via Healthline). If your symptoms get worse or you develop other symptoms not commonly associated with jet lag, then you may be dealing with another issue. If your symptoms haven't gone away or have gotten worse within a week after your arrival, you should call your doctor. 

The stress of travel, cabin air pressure and quality, dehydration, and proximity to other passengers' germs can increase your chances of getting sick while you're traveling, per Cleveland Clinic. If you're running a fever, experiencing nausea or vomiting, or if you have a cough or sore throat, it's a good sign that it's not jet lag you're fighting but a potential virus. 

Pilots, flight attendants, and business travelers may experience chronic jet lag and long-term circadian rhythm disturbances (via AASM). Not only can this affect their physical and mental capabilities in the short-term, but it may also have deleterious effects on long-term health. The body's biological processes are closely tied to circadian rhythms regulating hunger, sleep, metabolism, fertility, and mental state (via NIH). Long-term circadian rhythm disruptions are linked to several chronic physical and mental health conditions, including diabetes, depression, obesity, and bipolar disorder (via Physiology, Circadian Rhythm). 

Some early research shows that chronic let lag may even contribute to cancer development. According to a 2021 article published in the journal Aging, studies in mice show that chronic jet lag potentially increases cancer risk by altering molecular and metabolic processes. A 2018 study published in Environmental Health found that certain types of cancers were more common in flight attendants compared to the general population. More research is needed to confirm these findings and to determine ways to prevent potential long-term health risks for frequent flyers.