Jet Lag and Sleep

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.

What Is Jet Lag?

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.

Symptoms of Jet Lag

The most common symptoms of jet lag include:

• Sleeping problems: It may be hard to fall asleep when you want to, or you may wake up earlier than planned. Jet lag can also cause sleep to be fragmented.
• Daytime sleepiness: Jet lag frequently causes you to feel drowsy or tired during the day.
• Impaired thinking: You may experience problems with attention or memory or simply feel like your thinking is slowed.
• Hampered physical function: Your body may feel tired, and peak physical performance may be affected, which is especially notable for traveling athletes.
• Emotional difficulties: Some people with jet lag feel irritable, and evidence indicates that jet lag can exacerbate mental health problems, such as mood disorders.
• General malaise: Jet lag may make you feel malaise, which is a general feeling of discomfort, illness, or uneasiness
• Stomach problems: Jet lag can induce gastrointestinal problems like reduced appetite, nausea, or even constipation and irritable bowel syndrome.
• Sleep paralysis and seizures: In rare circumstances, jet lag may impact sleep architecture which may increase the risk of sleep paralysis and nighttime seizures.

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.

Can Jet Lag Have Long-Term Consequences?

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.

Causes of Jet Lag

lane 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:

• Trip details: The total distance, amount of layovers, time zones crossed, direction of travel, local daylight hours, length of time at the destination, and other specifics of a trip can affect jet lag.
• Arrival time: When you arrive at your destination may affect your circadian rhythm. For eastward travel, some evidence indicates that jet lag is reduced with afternoon arrivals compared to those in the early morning.
• Age: A person’s age may play a role in jet lag, although studies have found mixed results. People over 60 experience circadian changes that can make it harder for them to recover from jet lag, but some research in pilots found jet lag to be worse in younger people.
• Sleep before travel: Poor sleep in the days leading up to a flight can increase a person’s propensity for jet lag after traveling.
• Stress: Being stressed-out can keep the mind and body on-edge in ways that interfere with sleep and make it harder to cope with jet lag.
• Use of alcohol and caffeine: Many people drink alcohol and coffee during flights, and these substances affect the brain in ways that can disrupt sleep.
• Past history of jet lag: People who have previously had jet lag are prone to have it again.
• Individual variation: For reasons that aren’t fully understood, some people are more likely to experience circadian rhythm disruption with long-distance flights than others.

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.

How is Jet Lag Different From Travel Fatigue?

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.

How Can You Prevent or Reduce Jet Lag?

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 Exposure

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 and Sleep Aids

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.

Pre-Adjusting Your Internal Clock

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.

Creating a Plan for Overcoming Jet Lag

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 detaails.

Practical Tips for Reducing Jet Lag

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.

Before Traveling

• Schedule the first days of your trip: Make sure to give yourself time to sleep and follow your plan for light exposure. Build buffers into your schedule just in case you feel sluggish, and if possible, try to arrive days in advance of an important meeting or event so that you have time to acclimate.
• Minimize travel stress: Don’t wait until the last minute to pack or leave for the airport. Being in a rush can heighten stress and make your travels more difficult.
• Get quality sleep: Focus on getting quality rest for at least a few nights before your trip so that you’re not already sleep-deprived at the beginning of the trip.

During Flight

• Stay hydrated: Drink water to replenish fluids and counteract the dehydration that can occur in-flight.
• Limit alcohol and caffeine: Reduce alcohol and caffeine intake on-board or skip them entirely.
• Eat smart: Reduce the risk of digestive problems by eating healthy and light. Opt for fruits and vegetables over heavy, calorie-rich, fatty snacks.
• Stand up and move: Blood clots and stiffness can occur if you are seated for too long. Walking, standing, and gently stretching a few times during the flight may reduce these risks.

After Arrival

• Exercise: Find time for a walk or other light physical activity. Exercising outside to receive appropriately timed daylight exposure will help recalibrate your circadian rhythm.
• Limit alcohol, caffeine, and heavy meals: Avoid excessive caffeine, alcohol, or heavy and calorie-rich meals.
• Nap with caution: Avoid the temptation to take an extra long nap. Try to keep naps less than 30 minutes and only nap eight or more hours before your planned bedtime.