Written by
Eric Suni, Staff Writer
Medically Reviewed by
Dr. Abhinav Singh, Sleep Physician
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Long-distance plane travel is infamous for being inconvenient and uncomfortable. Due to the logistics of check-in, the stress of security lines, and hours being stuck in a confined space, many people find extended plane trips to be seriously taxing.
Jet lag frequently contributes to the physical burden of long flights. Jet lag refers to the misalignment of your body’s internal clock with the local time at your destination. This phenomenon often occurs when flying across three or more time zones.
Jet lag can throw off your sleep and cause other bothersome symptoms that persist for days or even weeks after a flight. Whether you’re traveling for business or pleasure, jet lag can negatively impact your trip.
For travelers, knowing about jet lag — including its symptoms, causes, and ways of reducing them — can make long-distance trips more pleasant and less disruptive to sleep and overall health.
Jet lag is a circadian rhythm sleep-wake disorder that occurs when your 24-hour internal clock, known as your circadian rhythm, does not match the local day-night cycle.
Under normal circumstances, a person’s circadian rhythm aligns with daylight, promoting alertness during the day and sleep at night. This internal clock synchronizes with the 24-hour day to promote quality sleep as well as physical and mental health. A person’s geographic location affects their circadian rhythm since sunrise and sunset occur at different times in different locations.
Jet leg generally happens when a person travels east or west across three or more time zones. For example, if you fly from Los Angeles to New York and arrive at 8 p.m., your body might still operate as if it’s in L.A. at 5 p.m. This jet lag can cause you to stay up later than you’d like, sleep at odd hours, or feel more tired than usual, among other symptoms.
The most common symptoms of jet lag include:
These symptoms arise after long flights to different time zones because the disruption to your circadian rhythm impacts how and when your body produces hormones that affect sleep and other bodily processes.
People with jet lag experience one or more of the symptoms listed above. Symptoms can begin immediately or set in a few days after arrival. Many people sleep well the first night after a flight only to encounter sleep problems in the following days.
Jet lag lasts anywhere from a few days to a few weeks. In general, symptoms persist for 1-1.5 days per time zone crossed, but the duration of symptoms varies depending on the person and their trip details.
Jet lag is usually a short-term problem that goes away once the body’s circadian rhythm has adjusted to the local time. For people who frequently take long-distance flights, such as pilots, flight attendants, and business travelers, jet lag can become a chronic problem.
A chronically out-of-sync circadian rhythm can create persistent sleep problems that may give rise to insomnia. A healthy internal clock is important for the overall health of the body, therefore chronic circadian rhythm disruption may raise the risk of disorders like diabetes and depression as well as some types of cancer.
Plane travel that crosses three or more time zones causes jet lag. Symptoms may be more pronounced as more time zones are crossed.
Most people find that jet lag is worse when traveling east than it is when traveling west. Jet lag differs based on the direction of travel because it’s generally easier to delay your internal clock than advance it. Jet lag does not occur on north-south flights that do not cross multiple time zones.
Not everyone who takes a long-distance flight gets jet lag. Multiple factors influence the likelihood and severity of jet lag:
Because there are many factors involved, it is hard to know exactly who will develop jet lag, how severe it will be, and how long it will last. However, it is common for at least mild jet lag to occur when more than three time zones are crossed during flight.
It’s normal to feel wiped out after you’ve had a long travel day. While this can be confused with jet lag, it’s often a result of travel fatigue. Travel fatigue includes symptoms like tiredness and headaches that can arise because of the physical toils of travel.
Airplane cabins, which have cool, dry, low-pressure air, can cause dehydration and susceptibility to respiratory problems. Air pressure changes can lead to bloating, and long-term sitting can cause leg swelling. It’s often difficult to sleep upright in an airplane seat, especially with in-flight interruptions, so getting quality rest in transit can be challenging.
All of these factors contribute to feeling exhausted after a long flight; however, this is distinct from jet lag.
Unlike jet lag, travel fatigue does not involve circadian rhythm disruption. For that reason, while travel fatigue usually goes away after a good night’s sleep, jet lag can persist for days or weeks until a person’s internal clock becomes realigned.
It is possible to have both travel fatigue and jet lag after a long-haul flight, but jet lag is far more likely to cause lasting and extensive symptoms.
Jet lag can have ruinous effects on a vacation, business trip, or athletic competition. As a result, travelers of all kinds strive to minimize the effects of jet lag.
The key to preventing and reducing jet lag is quickly realigning your circadian rhythm to synchronize with the time zone of your destination. Until this is achieved, steps can be taken to manage symptoms.
For very short trips, you may be able to avoid jet lag by scheduled activities, including sleep, to keep your circadian rhythm aligned with your home time zone. In this way, you avoid circadian disruption both during the trip and after you’ve returned home.
For travel lasting more than a few days, minimizing jet lag requires acclimating to the day-night cycle at your destination. The following sections address methods of reorienting your circadian rhythm and practical tips for reducing jet lag.
Light is the most powerful influence on circadian rhythm, and strategic light exposure may help adjust your internal clock to avoid or reduce jet lag.
The effect on circadian rhythm depends on the level and timing of light exposure. Sunlight has the highest level of illumination and the strongest circadian effects. Different types of artificial light can also influence circadian timing to a lesser degree.
Indiscriminate light exposure doesn’t resolve jet lag because the timing is critical. At certain times, light exposure can either advance or delay your internal clock.
Properly timed periods of both daylight and darkness can help sync your circadian rhythm with local time. When access to natural light is limited, light therapy lamps, also known as lightboxes, can deliver bright light exposure with greater circadian influence.
Melatonin is a hormone that the body produces that helps to both make you feel sleepy and govern your circadian rhythm. Melatonin is normally produced in the evening, a few hours before bedtime, but this schedule can get thrown off by jet lag.
There are both prescription medications and dietary supplements that boost the body’s levels of melatonin, and some research suggests melatonin can reduce jet lag.
Other types of sleeping pills, including prescription and over-the-counter drugs and natural sleep aids, may help you fall asleep or stay asleep, but they do not work to change your circadian rhythm. In some cases, they may even mask an ongoing case of jet lag.
Sleep aids can have side effects, including a heightened risk of falls and accidents if they increase drowsiness. Before taking melatonin or any other sleep medication, it’s best to consult with a doctor, ideally prior to your trip, to discuss the benefits and risks pertaining to your specific situation.
Some methods of preventing jet lag are based on modifying your sleep schedule in the days leading up to your trip so that when you arrive at your destination there is less of a discrepancy between your circadian rhythm and the local time.
In addition to changing your bedtime, this approach often involves carefully timed melatonin and light exposure to proactively alter your circadian rhythm.
While this approach may be beneficial in some cases, it may not be practical depending on your daily schedule, and professional, family, and social obligations.
The optimal plan to avoid jet lag depends on many factors including the direction of your flight, the number of time zones crossed, how long you will remain at your destination, and your schedule and obligations during your trip.
Taking these factors into account, you can create a personalized plan to reduce jet lag. Light and melatonin together can help you realign your circadian rhythm, but without proper timing, they can exacerbate rather than reduce jet lag.
A doctor, travel nurse, or sleep specialist may be available to help you prepare a plan for managing jet lag. Several online resources and apps can help you generate tailored schedules to help reduce jet lag based on your trip details.
A number of practical tips for before, during, and after your flight can help reduce sleep disruptions and travel fatigue so that you make the most of your trip.
Staff Writer
Eric Suni has over a decade of experience as a science writer and was previously an information specialist for the National Cancer Institute.
Sleep Physician
MD
Dr. Singh is the Medical Director of the Indiana Sleep Center. His research and clinical practice focuses on the entire myriad of sleep disorders.
