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Jet Lag: Symptoms, Risk Factors, and More

If you’ve ever travelled across the country, or even halfway across the country, you’ve likely felt the effects of jet lag. Jet lag is that general lethargy and crankiness we feel after bouts of air travel.

While jet lag is extremely common, it’s also fairly simple to prevent, given you take the right precautions. Keep reading to learn how to recognize when you have jet lag, how to avoid it, and how to recover if you do end up feeling it.

What Is Jet Lag?

Definition

Jet lag is a temporary sleep disorder categorized as a circadian rhythm sleep disorder resulting from traveling across different time zones.  The internal “clock” of the body, the circadian rhythm, becomes misaligned within the new time zone.

Circadian rhythm is the body’s 24 hour cyclical regulation of wake and sleep which relies heavily on external environmental stimuli; light exposure in particular. The circadian rhythm works in collaboration with the body’s homeostatic sleep debt process to create a regular sleeping schedule. The body’s homeostatic sleep debt process refers to the cyclical drive to sleep following periods of wakefulness; meaning the longer someone is awake the drive or “pressure” to sleep begins to increase until it has reached a maximum peak. Once sleep is obtained, the drive decreases allowing the cycle begin again upon waking.

The role of light is vital to sleep regulation in the brain. The level of light indicates to the brain whether or not it is time to be alert and high functioning or whether it is time to begin relaxing and preparing for sleep. Light exposure determines when the brain initiates melatonin production.

Melatonin levels vs body temperature and sleep cycle

Melatonin is a hormone produced in the brain responsible for the gradual descent from full wakefulness to drowsiness, to sleep.  Following the extrinsic factor of daylight, melatonin steadily begins to increase in the evening as daylight begins to wane, peaks at night during sleep and is lowest in the morning and during the day.

The importance of light exposure can be seen in those experiencing seasonal affective disorder or seasonal depression.  Common in regions where sunlight is decreased during particular seasons like winter, seasonal depression can result in decreased energy, lethargy and hypersomnia or excessive sleeping.  Due to the lack of sunlight, there is an overproduction of melatonin resulting in an increase in sleepiness.

Therefore, when traveling far distances, the amount of light exposure received by your brain can be altered depending on location.  Such changes can create discord within the circadian rhythm of the body; losing light sooner in the evening by traveling east or far north or losing light later than the body is used to by traveling west or south can disrupt natural sleeping patterns.

What Is Social Jet Lag?

Social jet lag, though different than standard jet lag, can occur with or without travelling. Social jet lag refers to the misalignment of a person’s own biological time and that of traditional social time, time spent at school or work or out in public.

People affected by advanced sleep-wake phase disorder (ASWPD) or delayed sleep-wake phase disorder (DSWPD) have sleep-wake cycles that are out of sync or offset from normal, conventional sleep-wake cycles. The circadian rhythm does not match with common social constraints and leaves people with ASWPD or DSWPD feeling mismatched within the social world around them. The results include a sensation similar to that of standard jet lag; difficulty being alert, sleepiness or trouble focusing.

Social jet lag can also refer to sleep timing discrepancies that may occur between work days and free days. Different sleeping patterns on the weekends or on days away from work can negatively impact sleeping patterns that occur during the work week.

For example, if someone typically goes to bed at 10pm and awakens at 6am during the work week, but then on Friday does not go to bed until 1am and then sleeps until 9am or later, the internal shift that occurs creates a similar sensation to that of someone experiencing traditional jet lag.  Trying to return to a 10pm bedtime on Sunday may be difficult due to the differences in the timing of sleeping patterns during the weekend hours or days off from work.

Jet Lag Symptoms

About a third of people experience jet lag to a minimal extent, while another third experience more extreme symptoms. Common symptoms of jet lag include:

  • General malaise
  • Daytime sleepiness
  • Difficulties initiating or maintaining sleep (i.e. insomnia)
  • Early waking
  • Impaired performance
  • Reduced alertness and difficulty focusing
  • Increased irritability
  • Digestive and bowel movement problems

Symptoms are worse the farther you travel, but traveling east is always worse than traveling west. Eastward travel generally results in difficulty falling asleep and westward travel in difficulty maintaining sleep.

Jet lag can also be made worse by the airplane itself. Airplanes tend to have poorer air quality, lower humidity, and cramped conditions. Lower humidity results in dehydration, while being forced to sit still for a long flight makes the body achy.

Who’s at Risk for Jet Lag?

Morning larks, or those who consider themselves “morning people” and do not have difficulty waking early in the morning are more affected that those who consider themselves night owls.  Night owls typically enjoy staying up later and do not have an easy time awakening early in the morning. Adults over the age of 50 are at greatest risk.

People who travel frequently, such as flight crews and business travelers, are most at risk for jet lag, since they are constantly in different time zones and therefore their body has trouble settling into a steady circadian rhythm.

People with pre-existing sleep issues or stress also tend experience stronger symptoms, as well as anyone who overindulges in caffeine or alcohol.

How Long Does Jet Lag Last?

These symptoms usually last for several days until the traveler adapts to the new time zone. A good rule of thumb is that it takes about a day per time zone traveled to recover.

Senior citizens generally need longer to recover from jet lag. Their circadian cycles are slower to adjust to the new time zone.

Eastward travel (requiring advancing circadian rhythms and sleep-wake hours) is usually more difficult to adjust than westward travel.

If you travel somewhere with a higher altitude, expect that to lengthen your recovery time, too. It can take as long as 3 weeks for your body to fully adjust, thanks to the lower oxygen levels at altitudes of 13,200 feet or more.

How to Reduce the Effects of Jet Lag

Since jet lag cannot be avoided or prevented entirely, there are multiple ways to minimize the symptoms and help your body adjust accordingly upon arriving in the new time zone.

Before Travel

  • Begin adjusting your sleep schedule more in line with the time zone you will be traveling to.  If traveling west, go to bed 1-2 hours later than usual. If traveling east, adjust bedtime 1-2 hours earlier than normal to prepare your body in advance.
  • Be sure to be as well rested as possible to prevent becoming overtired prior to leaving.
  • Try to book flights that align well with your sleep schedule to lessen any disruptions.
  • If possible, select seats with additional room for added comfort or those near the window to avoid unnecessary disruption.
  • Check with a medical professional about treatments that require a strict schedule such as insulin or titrated medications.

During Travel

  • Avoid large, heavy meals. Instead eat smaller, lighter meals with protein.
  • Avoid or minimize alcohol or caffeine consumption as both can disrupt sleep. The sugar in alcohol can cause dips in blood sugar levels causing arousals and sleep fragmentation. Furthermore it can produce an increased need to urinate which also causes sleep disruption and poor sleep quality. The “hangover” effect that occurs with alcohol will only add to the symptoms of jet lag.  Caffeine can make falling asleep difficult and should be limited to avoid any difficulties if possible. Smaller doses spread out throughout the day, if necessary, are better than consuming larger quantities.
  • Drink plenty of water to remain properly hydrated.
  • Bring anything that can aid and assist in trying to sleep or rest on the plane. This can include eye masks, earplugs, travel pillows, noise cancelling headphones, quiet, soothing music or anything personal that assists in normal sleep onset. Shorter nap periods (20-30 minutes) are acceptable while flying on long flights that are not during the overnight period.  Longer naps can interfere with the sleep cycle causing even more disruption while traveling.
  • If planning to rest or nap on the airplane remain buckled as to avoid disruption from the flight crew.
  • Get up, move around, or stretch either in the airport during a layover or during the flight to avoid sitting too long.  Sitting for extended periods can leave a person at higher risk for blood clot formation.

After Travel

  • If arriving at the destination at night, make proper arrangements for sleep while trying to maintain normal sleep hygiene as at home. Aim to get as much sleep as would normally occur within a 24 hour period; it is recommended to try and get at least a minimum of 4 hours of sleep on local time.  This “anchor sleep” is thought to assist the body’s internal clock to adjust to the new time zone. Additional sleep can be gotten the following day with short naps if necessary.
  • If arriving in the daytime try to remain awake.  If sleep is needed, limit sleep to a two hour period to avoid delaying overnight sleep onset within the new time zone.
  • Appropriate exposure to sunlight can also assist with adjusting to the new time zone.  If traveling west, spend time in the sunlight in the afternoon. If traveling east, get sunlight in the morning.
  • Melatonin may be useful in obtaining sleep.  Taken approximately 30 minutes before bedtime, melatonin serves to relax and prepare the body for sleep.  Even a small dose of melatonin (0.5mg) can be utilized for effectiveness.
  • Medications that assist with sleep onset may be helpful, but only under the guidance of appropriate medical personnel. If they are not used ordinarily, use of sleeping medication may actually add to the severity of jet lag symptoms.
  • In the absence of sunlight, bring a portable light therapy device to help you adjust. These devices come in many shapes and forms, from traditional-looking lamps to wearable visors, and are designed to mimic bright 10,000-lux sunlight without the UV rays. Use yours in the morning to help you wake up easier for eastern travel, and use it at night if you traveled west. You can get a larger lamp device for your home to help you adjust upon your return.
  • For extreme travel (8 time zones or more), you’re at risk of completely inverting your schedule, so you have to time your exposure to light accordingly to avoid your body confusing dawn for dusk, or vice versa. If you traveled west, avoid sunlight in the early evening. If you traveled east, wear sunglasses and avoid sunlight in the morning. In the late afternoon, take off the sunglasses and go outside or otherwise expose yourself to bright light. The charts below, from the Cleveland Clinic Journal of Medicine, suggest when a traveler should seek out light (L) or darkness (D).

jet lag plan for 9 time zones east jet lag plan for 7 time zones east

Jet Lag Recovery

Jet lag is a temporary experience and will resolve within 2-3 days of arriving within the new time zone. The number of days to recover or adapt equals the number of time zones that were crossed.

Additional methods to consider when trying to adjust to a new time zone include:

  • Sun exposure at appropriate local times to aid in syncing the body’s natural rhythm and melatonin production.
  • Exercise can assist in energizing a traveler in the morning and helping to relax he/she at night. However, avoid exercise at least 2 hours before bed.
  • Observe and partake in social activities within the local social schedule. For instance, go to dinner or other events when it is common for that particular time zone.
  • Practice regular and already established sleep hygiene. Whatever normal routine is done nightly should be continued in the new time zone to assist the body in preparing for sleep. Proper sleep hygiene acts as cues to the body that it is time for sleep and may help curb “first night effect.” First night effect typically occurs the first night sleeping in a new sleep environment and usually subsides quickly.
  • Try to replicate the normal sleeping environment. Adjust the thermostat to a cool mid-60 degrees Fahrenheit. Comforting smells, sounds or textures can all aid in creating a familiar place for sleep. If you typically sleep with a sleep mask, do so in the new time zone. The same is true for sounds or light. If you sleep in complete darkness mimic what would be normal to you. Try to maintain what is comforting and recognizable as a means for better quality sleep.

Additional Tuck Resources

Take a look at Tuck’s informational guides on getting to bed while you’re traveling:

Be sure to consider the products below as key tools in your suitcase for great sleep:

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