What is Jet Lag: Causes, Symptoms, and More

Blog Updated: May 21, 2024

Stepping off a plane only to be greeted by disorientation, exhaustion, and a sense of being out of sync with the world is a clear sign you've encountered the mysterious world of jet lag.

Below, we'll discuss this common travel-related condition, explain why your body struggles to keep up after traveling multiple time zones, identify the symptoms of jet lag, and, most importantly, offer helpful methods to prevent and manage it.

The goal is to make your travel experiences more comfortable and your recovery faster -- ultimately conquering it!

Did You Know: Jet lag can occur anytime two or more time zones are crossed.

What is Jet Lag

It's also referred to as circadian desynchrony. [1] It can feel like your body's own version of time travel confusion! It occurs when you cross numerous time zones quickly, usually by flying. Your body has an internal clock, known as circadian rhythms.

These rhythms indicate when it's time to eat, stay awake, and when to sleep. Your body's circadian rhythms get out of sync with the time in the new place. [2]

For instance, imagine you board a flight in New York at night, arrive in Paris, and find it's already morning. Your body is saying, "Hey, it's bedtime," but it's sunny in Paris, and then your body is saying, "Nope, it's time for croissants and coffee!"

This mismatch can cause fatigue, sleep issues, and an effect on appetite. Your body is trying to play catch-up, but it takes some time to adjust to the new time zone. Basically, jet lag is when your body and the clock don't quite agree!

Social Jet Lag

Do you ever feel like you've flown through numerous time zones but have yet to leave the comfort of your home? Check out our blog about social jet lag and discover how your weekend habits might be behind your daytime fatigue.

What Causes of Jet Lag

People of all ages experience jet lag, but it is often more challenging for older adults to adapt to new time zones.

Researchers agree that traveling from west to east results in more severe jet lag symptoms than traveling from east to west due to crossing more time zones. But, when traveling from north to south, or vice versa, one may experience travel fatigue due to disturbed sleep or tiredness, as no time zone is crossed.

Which Direction is Worse for Travel?

Reports indicate that people traveling across multiple time zones to the east experience more issues than those traveling the same number of time zones to the west. This difference is primarily due to how our internal body clock, or circadian rhythm, adapts to the new time zone.

Traveling East

Traveling east shortens your day, conflicting with your natural circadian rhythms that typically extend slightly longer than 24 hours. Flying east is generally considered worse for jet lag, and there are several reasons behind it.

Our bodies find it harder to adjust to a shorter day than a longer one. When you fly east, you are essentially "losing time," and your body needs to play catch-up. You may have to force yourself to sleep and wake up earlier than your body prefers.

Adjustment to new time zones can be difficult, resulting in intense jet lag symptoms like fatigue, sleep disturbances, and cognitive impairments.

Jet Lag Sleep Study: Roughly 75% of people experience worse jet lag when traveling east compared to traveling west. [3]

Traveling West

On the other hand, westward flight is often easier on your body. This direction extends your day, aligning somewhat more comfortably with your natural circadian rhythm's tendency to run longer. When flying westward, you "gain time," and your body can more naturally adapt to this extended day.

While you might still experience jet lag, the symptoms are usually less severe compared to when you travel east.

Note: For each time zone crossed during travel, it takes roughly a day to adjust to the new location.

Jet Lag Symptoms

If you are not familiar with it, you may experience one or more of the following symptoms:

• Daytime fatigue
• Disturbed sleep patterns (insomnia, early waking, or excessive sleepiness)
• Difficulty concentrating or impaired thinking
• Restricted physical functionality
• Stomach problems, including lack of appetite or nausea.
• Tremendous lack of focus
• Headaches often occur
• General malaise, which is a feeling of discomfort or illness
• Excessive tiredness during the day
• Shifts in mood throughout the day, such as anxiety or irritability

Remember, everyone can experience jet lag a bit differently. Symptoms can kick in immediately or take a few days to appear after you arrive. It's common for people to sleep well the first night post-flight from sheer exhaustion but then encounter sleep disturbances in the following days.

Fortunately, jet lag symptoms improve steadily as the body gets used to the new time zone. [4]

Did You Know: 60-70% of long-haul travelers will experience some form of jet lag symptoms and overnight travel causes the most sleep loss.

How to Prevent Jet Lag

Have you ever experienced the uncomfortable feeling of being groggy or disoriented after a long flight? Well, you're not alone. Fortunately, there are ways to overcome those pesky symptoms and adjust to your new time zone.

Read our blog on how to avoid jet lag, which highlights 15 strategies that really work.

How Long Does Jet Lag Last?

The symptoms depend on different factors. Traveling from west to east requires a more extended recovery period, which can last four to five days. Some specialists in sleep medicine say that traveling over just one or two time zones is minimally problematic.

A good rule of thumb is about a day per time zone. Other factors to consider are the utilization of treatments and pre-flight strategies

Individuals who encounter jet lag feel better a few days after arriving at their destination. But it can take up to one week for some people to feel back to themselves.

When to Be Concerned

If you are a frequent traveler or work in the aviation industry, it's important to know when to seek professional advice about your sleep. Contact a sleep specialist or physician for long-term advice on sleep hygiene practices and medications that suit your needs. Be especially mindful if:

• The symptoms of jet lag last longer than about a week. Remember, jet lag symptoms can sometimes mimic other illnesses.
• Symptoms become serious enough to cause significant disruption to your business or vacation plans.

Seeking professional advice can help ensure your sleep health is managed effectively, allowing you to maintain your well-being despite frequent travel.