Why are Long Flights so Exhausting? The Truth about Jet Lag

jet lag


  • Jet lag is disruptive to your sleep and your health

  • You can prepare for jet lag in advance to reduce its effects

  • Treat symptoms of jet lag by resetting your circadian rhythm

Have you recently taken a trip and haven’t quite felt like yourself since? If you are thinking that one flight couldn’t possibly be the cause of your sleep problems, think again! Jet lag is incredibly common for people traveling across multiple time zones because your circadian rhythm (you know, the thing that’s supposed to tell your body when it’s time to sleep?) gets thrown out of sync.

What exactly is jet lag?

Jet lag is a temporary sleep disorder that occurs when your body is synced to a different time zone than your current environment. Essentially, it’s like your body is in one time-zone while your mind is stuck in another.

For every day you’re in a different time-zone, the area of your brain that adjusts your circadian rhythm can only readjust by about one hour. This equates to about one to two time-zones per day. Not ideal if you’ve just crossed six!

How might jet lag be impacting my sleep?

It causes insomnia: When your circadian rhythm is out of sync, your body may not be tired during the “appropriate” sleep times. This can make it difficult to fall asleep and stay asleep at night.

It reduces sleep quality: Disruptions to your circadian rhythm can mean that your body is sending wakefulness signals while you try to sleep. As a result, the quality of your sleep declines, leading to extreme sleepiness and lethargy throughout your day.

How could jet lag impact my health?

Jet lag places physiological strain on several different areas of your brain that are important for regulating your circadian rhythm. When your brain is starving for sleep, it causes your brain cells to work at a much slower pace. Sleep deprivation caused by jet lag can affect all key areas of functioning:

  • Brain: The neurons in your brain are firing more slowly when they are tired. This can lead to poor concentration and performance, slower reaction times, and can affect your balance and coordination.

  • Body: Lost sleep can weaken your immune system, increase your blood pressure, put you at a higher risk of heart disease, and cause headaches and gastrointestinal problems.

  • Mind: The strain on your brain and body can cause you to feel cloudy, unsteady, anxious, and irritable. More severe cases of sleep deprivation can lead to depression, and can even cause hallucinations.

Does the direction I'm travelling make a difference?

Yes, knowing the direction you are traveling (east to west, or west to east) can make a difference in how jet lag might impact you. You can use this information to better implement strategies to deal with the symptoms. It is easier for your brain to stretch a day than to shrink it, so the symptoms of jet lag may be harder on your body if you are traveling west to east.

Are there ways I can prevent jet lag from happening?

Great news! If you try implementing these changes into your life before your travel plans, you may be able to prevent jet lag from taking over your trip!


  • Adjust your time to your “destination time”: Try shifting your sleep-wake schedule by an hour each day, for the few days leading up to your trip. Westward travelers would shift their schedule by 1 hour later. Eastward travelers would shift their schedule by 1 hour earlier. Setting your watch to your “destination time” can also help you adjust in advance of the time change.

  • See the light: Using light therapy ahead of time can help prevent the severity of jet lag symptoms. See the table below to ensure you’re using the right light therapy strategy, as it changes depending on your direction of travel:

Avoid bright light for the first few hours after waking up and try to get as much natural light exposure in the early evening to avoid feeling sleepy prematurely. Light exposure in the evening can shift your circadian rhythm forward and help you adjust better.
Getting plenty of light exposure in the morning boosts your hormone production for natural wakefulness. This helps you to shift your circadian rhythm into your new time zone in advance.
  • Hydrate, hydrate, and hydrate: Planes are very dry. Dehydration can make symptoms of jet lag much worse. Keep well hydrated before (and during) your flight to ease or prevent the effects of dehydration. Try to avoid alcohol during your flight or offset it with some extra water.

  • Arrive early: If possible, try to arrive at your destination as early as possible to get a head start on dealing with those jet lag symptoms!

What are the best ways to deal with jet lag?

You can’t always prevent jet lag but you can use some strategies to make it more tolerable. By working with your body’s circadian rhythm, improving your sleep environment, and some quick-win strategies– you can take some of the lag out of your trip.


Your body’s rhythm has been disrupted, its signals are mixed, everything is a mess. Fortunately, you can help your brain sync to your new time zone using some of these strategies:

Light therapy

Light is the strongest mechanism available for synchronizing our circadian rhythms. Light exposure can help to reset the timing of the circadian pacemaker. For each day of your trip, try adjusting the timing 1 hour earlier/later depending on your direction. Use the table below to determine the right advice for your direction of travel:

Avoid exposure to light in the morning. Use sunglasses or window shades to avoid natural sunlight, and wait to get your light exposure between 12pm-2pm.
Avoid exposure to light first thing in the morning. Try getting a bunch of light exposure between 9am-12pm.


Abstaining from food through intermittent fasting and then indulging in a big meal can shift your circadian rhythm by tricking your mind into thinking it’s morning.

Try fasting for 16 hours prior to when your flight is set to arrive at its destination to reset your biological clock. Fasting does not include hydration! Do not forget to hydrate, hydrate, hydrate!

When you arrive at your destination have your big meal as close to your usual eating time as possible. So, if you normally have breakfast at 8am you should wait until 8am destination time to eat your big meal.

It is best to use this method only if you are already accustomed to fasting or if you have been advised by a professional to do so.


Moderate-intensity physical activity (65-75% heart rate) can help shift your circadian rhythm. Use the table below to determine the right advice for your direction of travel:

Exercise for at least 1 hour in the afternoon to help create an earlier bedtime.
Exercise for at least 1 hour in the evening to help push your bedtime later.


Creating a cozy sleep environment can help ease your body into slumber, even in the face of jet lag.

  • Earplugs: If you sleep better in silence, make sure to pack a pair of earplugs to cancel out environmental noise.

  • Soothing sounds: White noise, pink noise, or environmental sounds (such as wind chimes or ocean waves) create a calming environment that helps you relax before falling asleep. You can use apps on your phone to bring the sounds with you anywhere you go.

  • Sleep masks: A darker environment helps to signal your melatonin production. Melatonin is a hormone in your body responsible for regulating your sleep cycle.

  • Lower the room temperature: Set the temperature to 65℉ (18.3℃). Sleeping in a room with a cooler temperature can also give you a better night’s sleep.

  • Melatonin: It is recommended to take a small dose (0.5mg) of melatonin after dark, approximately 30 minutes before you want to fall asleep.

Learn how to build yourself a sleep sanctuary with our step-by-step comprehensive guide.


Jet lag causes stress to your mind and body, and sometimes you need to decompress. Try stepping up your mental decompression with these techniques. 

Deep breathing

Deep breathing activates your parasympathetic nervous system (the calm you down system). It’s easy to do– take a deep breath in through your nose, hold it (about 3 seconds), then, slowly breathe out through your mouth. Repeat this four times to go to Relaxville. Learn more breathing techniques for relaxation.


Try a guided track or simply set a timer for 5-10 minutes and sit comfortably with your eyes closed while focusing on your breathing. Release your thoughts as they come and sink into calmness. Learn more meditations techniques for relaxation.

Soak yourself

Researchers have found that taking a warm shower or bath one or two hours before bedtime can help people fall asleep 36% faster. Adding some lavender bath salts or oils can also help to prepare you for sleep, as lavender has been known to aid in relaxation and sleep.

Take a walk

Walking is a great way to let go of stress. Walking outside is even better as fresh air can help reduce stress and improve sleep.

Now that you know what to do, lets talk about what not to do...

Strategies to avoid:

Some popular ways to manage the effects of jet lag can leave you worse for the wear. Here’s what you need to avoid:

  • Alcohol before bed: Drinking alcohol within three hours of bedtime may help you doze off but is very disruptive to your sleep cycles as it’s metabolized. These negative effects on sleep can occur from drinks consumed six hours before bed. jet lag makes the issue worse, so try and avoid booze while adjusting (or time it well and do it in moderation).

  • Caffeine: Caffeinated beverages like coffee, tea, or pop can give you the energy boost you need during the day, but it can come at a cost. Caffeine has a half-life of four to seven hours, which means if you have 200 mg of coffee at 5 pm, by 10 pm there’s still 100 mg kicking around inside of you. Heavy doses during the day can seriously disrupt your body’s mechanisms that regulate your sleep drive.

  • Try skipping a night of sleep: Could it be so bad to just stay awake instead of struggling to get to sleep at night? The short answer is yes. Unless you’re under the guidance of a physician, sleep deprivation is generally a bad idea. Any sleep is better than no sleep.

  • Take a long daytime nap: Naps are tempting (and easy to do) while in a state of jet lag. Unfortunately, long naps can cause more disruption to your nighttime sleep. If your body needs a nap during the day, try napping for no longer than 30 minutes.


  • Prepare for your trip ahead of time by using techniques like light exposure
  • Travel with sleep-aids such as sound machines, sleep masks, and earplugs
  • Avoid disruptive strategies like alcohol before bed or too much caffeine
Bottom Line: Jet lag can be a very annoying travel companion. You can minimize its impact in advance by adjusting your schedule in the days before your trip, or using techniques like light and activity to help adjust to your new time zone after you’ve landed. Amp up your sleep environment and add some quick-win strategies to help ease your adjustment period. Jet lag doesn’t have to ruin your trip, just approach it with a little circadian wisdom.


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