What Is Jet Lag?

The most important part of the term “jet lag” is the lag. Jet lag occurs when you go from one time zone to a new time zone. Your body clock is disrupted by this change and your body and brain both lag behind.  

Jet lag is also called travel fatigue and jet lag disorder. Symptoms of jet lag include fatigue, insomnia, and brain fog. Jet lag is a circadian rhythm sleep disorder. It’s a disruption in your natural circadian clock, which regulates your sleep and wake cycles. Jet lag causes sleep problems and daytime sleepiness.

Jet lag symptoms are often taken lightly, but they can be quite serious and impact the whole body. In addition to general fatigue, a person suffering from jet lag can experience anxiety and confusion. Physical side effects of jet lag can impact your ability to function normally. Side effects of jet lag include constipation, diarrhea, dehydration, headache, and nausea.

Causes of Jet Lag

Your body’s natural processes are affected when air travel takes you across different time zones. A change in time zones causes you to experience daylight and darkness differently than you normally would. As a result, your body clock struggles to adapt. In your body’s attempt to regulate itself, it tries to hang on to your normal sleep, wake, and eating patterns.

Your body clock is controlled by a daily biological pattern called your circadian rhythms. These circadian rhythms are internally-generated 24-hour cycles that persist even in constant conditions, allowing our bodies to predict the changing light and dark we experience as a result of the earth’s rotation.

Jet lag can be annoying, but your circadian rhythms are important body processes. Under normal circumstances, they keep you functioning and keep your body healthy with everything occurring at the right time.

Your circadian rhythm controls hunger, sleep, and wakefulness. When you eat and sleep at unpredictable times, your body becomes confused. Although you might not realize it, you likely become awake, hungry, and tired around the same time each day. The goal of your body clock is to continue that pattern to optimize your body to the environment in which you live.

The Role of Melatonin in Jet Lag

Numerous factors are influenced by your circadian rhythm. Two important examples are the secretion of the hormone melatonin and your body’s natural fluctuations in core body temperature. Melatonin is secreted at night as a signal to tell your body it is dark, and your body temperature cools when it’s time for sleep.

These two processes work together to get you a good night’s sleep exactly when you need it, though other mechanisms – such as how long you have been awake – also play an important role.

In most people, melatonin levels begin to rise about two hours before your normal bedtime. (This is why it’s so important to go to bed around the same time each night.) Melatonin secretion is associated with a drop in your core body temperature.

In the morning before your alarm goes off, melatonin levels slowly drop. At the same time, your core body temperature rises, signaling to your body that it’s time to start your day. (Again, why it’s a good idea to wake at the same time each day.)

How Does the Body Clock Work?

Certain factors influence your circadian rhythms and biological clock. These factors include bright light, exercise, meals, and even social interaction. However, the most important time cue is light.

Air travel and long flights relocate you to a new time zone. While on the plane and at your destination,  you move your body, eat, and experience bright light or darkness at abnormal times. These activities disrupt your internal clock, creating a mismatch between your biological clock and your new environment.

As a result, melatonin secretion and core body temperature will cycle at inappropriate times, contributing to the feeling of jet lag. Many people say jet lag is a “hangover” type feeling. This is as a result of your circadian rhythms telling your body to be sleepy when you need to be awake.

“Our sleep is regulated by two processes. Firstly, how long we have previously been awake. Secondly, our circadian clock helps us feel awake or sleepy at an appropriate time of day. Jet lag is the result of our circadian clock being misaligned with the time at our destination,” says Professor Stuart Peirson at the University of Oxford.

How Do You Cure Jet Lag? 

Every person’s body will react to changes in time zone and light exposure, so jet lag cannot be cured, but the symptoms of insomnia and daytime sleepiness can be addressed. The goal is to help your body’s circadian rhythm readjust to the new location. Once your body adjusts, rhythms in melatonin and core body temperature will also adjust. Over time, they will regulate your sleep-wake cycle to the appropriate times for your new timezone, and you will feel at home in your new time zone.

Your body will eventually recover from the symptoms of jet lag without any treatment. However, there are some treatments that can help you manage symptoms. With some preparation and a plan in place, you can adjust faster to a new lightness and darkness cycle in your destination time zone. Although some products might be marketed as a quick fix for jet lag, the true cure is based on allowing your body to adapt to the new time zone, which can be facilitated by sunlight, nutrition, and hydration, with light playing a particularly important role.

Jet Lag on a Short Trip

If your trip is a couple of days or less, there’s no sense planning on adjusting to the new destination time zone, as there will not be enough time for your body to adapt. Instead, focus on staying on your home schedule. Staying on your home schedule in your local time will help you return home awake and alert at the right times.

Go to bed and wake up at the same time you would at home. Eat your meals around the same time you do each day. Don’t expose yourself to bright light before your normal wake up time or after your normal bedtime.

Preventing Jet Lag

Researchers have been studying methods to lessen the effects of jet lag. Studies on bright light therapy have produced favorable results.

When you arrive in your new time zone, you can strategically expose yourself to light.  The best source of light is light from the sun itself, as it is far brighter than artificial light sources.

If you can’t get sunlight due to weather, you can also use a lightbox. These types of lightboxes can be purchased online and are often marketed for depression and seasonal affective disorder.

If you have crossed three to five time zones while travelling west to east, you want to avoid bright daylight after the sun rises on the day you arrive. Instead, seek out bright light in the mid-morning. Your wakefulness will be triggered by the bright light and your circadian clock will start shifting to your new time zone.

When you cross six or seven time zones, avoid bright light in the morning and get out in the sun in the early afternoon. Try to stay up until you are so sleepy you can’t function, or around a normal bedtime hour in your new time zone. Over the next few days, time your light exposure to be gradually earlier each day.

When traveling east to west, you may find yourself feeling sleepier earlier than desired. Exposing yourself to light throughout the day can help you get on a more manageable sleep schedule.

Decreasing the Likelihood of Jet Lag

If you’re really motivated to avoid jet lag, you can prepare for your trip across time zones by changing your sleep schedule before you leave. This may help you avoid sleep problems at your destination when you arrive.

Depending on whether you’re going east to west or west to east, you can expose yourself to bright light either one hour earlier or one hour later each day, likewise with going to bed either one hour earlier or one hour later each day. There are a number of apps and online sleep calculators offering to help adjust your sleep schedule and determine your best bedtime.

But be aware that if you are shifting your clock in advance, you will need to avoid sunlight at home when it would be dark at your destination. Otherwise, this will override your efforts to shift your clock in advance.

Start prepping for your trip at least a week before you arrive. If you’re already on the sleep and eat cycle of your new time zone, you’ll feel amazing when you reach your destination. This is an especially great plan for travelers or business people who want to squeeze a lot of hours into their trip. When you’re already adjusted, you can hit the ground running without missing a beat. 

Preparing for the Mental Strain of Jet Lag

It’s also wise to have realistic expectations of your first day or two in your new time zone. Plan on being tired, irritable, and maybe a little anxious. Then you’ll be better prepared to handle those feelings if they arise. 

Some people who are sensitive to body clock changes even say they feel depressed from jet lag. If you suffer from depression or anxiety, consider talking with your healthcare provider before you travel over a large number of time zones. They can help you create a plan of action in case you feel mentally unsafe. 

Jet lag can be stressful on your mind and your body. Stress is associated with a decreased immune response. Many people who travel fall ill while on their trip due to changes to the immune system from jet lag. You can prepare for traveling by keeping your immune system healthy. Get enough sleep, eat a diet of fresh fruits and vegetables, and make sure your vitamin and nutrient needs are met. 

Common Questions About Jet Lag

If you’re wondering about jet lag and its effects on the body, you might be in the middle of or preparing for a big trip. The sooner you recover from jet lag, the more you can enjoy your vacation or get back to business. Managing jet lag can also be critical when traveling with children who are generally very sensitive to changes in circadian rhythm. So let’s take a look at some of the most common questions about jet lag and get you answers to help you recover easier. 

What is jet lag and how long does it last?

Jet lag is a biological reaction to changes in daily habits including sleeping and eating. Jet lag mimics the feeling felt by shift workers as they flip flop from day shift to night shift. It is particularly impacted by exposure to bright light.

This is because bright light changes the time of the circadian clock which controls rhythms throughout the body. When you arrive in a new time zone feeling out of sorts, it can be alarming. You might worry you will spend your whole trip feeling misaligned.

How long do you need to recover from jet lag?

A good rule of thumb is to allow yourself one day to recover from jet lag for each new time zone you cross. (Some people are able to recover from time zone changes faster.) After one to two days per time zone in a new location, you should be feeling back to normal. Some people are much more sensitive to environmental differences and can take longer to adjust.

Common symptoms of jet lag can be exacerbated by dehydration, hunger, and stress. The changes in air pressure and oxygen you experience during air travel can lead to dehydration. Drink plenty of water and eat fresh fruits and vegetables as you try to adjust to your new time zone. Avoid slugging through the day with caffeine that could just lead to increased sleep problems. Jet leg can feel awful, but thankfully it is temporary.

Is jet lag worse from West to East?

When traveling from west to east, jet lag may be intensified. Your body’s internal clock will not feel tired until it’s far past your bedtime. When it’s time to wake up, it will feel like you are being woken in the middle of the night. Traveling west is somewhat easier. You will feel tired earlier and want to wake earlier, which most people don’t find as bothersome.

Jet lag can also be more severe when traveling from an east to west time zone while also swapping north hemisphere for south hemisphere. Flying over the equator means your new time zone will also have a different season. Temperature and light differences related to the seasons will intensify the time difference. These changes can further stress your body’s inability to adjust its body clock. Unfortunately, science has yet to identify a way to gracefully adjust to quick changes in weather and seasons.

Does drinking water help jet lag?

Yes, drinking water can make it easier to deal with jet lag. Instead of drinking a caffeinated beverage, which can throw off your sleep schedule,  Try to eat lightly as well while you’re flying because heavier meals are harder to digest at high altitudes.

Should I nap when jetlagged?

Napping can help if you’re trying to fall asleep later instead of earlier. If you’re traveling west, a nap can help you adjust to a new time zone. However, you want to avoid naps if the goal is falling asleep earlier than you’re used to. If you are feeling so tired it is hard to function, a short nap can help you adjust your routine to your new time zone.

So, What Is Jet Lag? 

The symptoms of jet lag can put a damper on your trip to a new time zone. You may feel groggy, irritable, or even dizzy. It’s not uncommon for people who travel across time zones to come down with an illness because the stress of jet lag can weaken the immune system.

Flying from east to west can worsen the effects of jet lag. Flying from north to south or vice versa adds more complications associated with a quick change in seasons.

You can help your body clock cope by avoiding bright light exposure at certain times when you arrive at your destination and seeking out light at other times when it will help move your clock to the new time zone. You can also prepare your body clock in advance by sleeping and waking at the time coinciding with the time zone to which you are traveling.

When you have a big trip coming up, it’s natural to be worried about jet lag. You want to get the most out of every minute of your trip. Preparing with an adjusted sleep schedule and light-exposure plan can help your body clock adjust before you even take off.