Jet Lag: Causes, Symptoms & How to Prevent It
Ana Marie Schick: Resident Sleep Expert and Certified Health Coach • Aug 23, 2022

Key Takeaways
Jet lag is a temporary sleep and energy disruption caused by traveling across time zones faster than your internal clock can adjust. It affects sleep timing, alertness, digestion, and mood until your circadian rhythm realigns.
- Jet lag occurs when your circadian rhythm is out of sync with a new time zone, leading to fatigue, headaches, and mood changes.
- Eastward travel often feels harder than westward trips because it shortens your day and challenges sleep timing.
- Gradually adjusting sleep and wake times before travel can help your body adapt more quickly after landing.
- Natural light exposure—especially in the morning when traveling east—helps reset your internal clock.
- Staying hydrated and limiting alcohol while flying can reduce the intensity of jet lag symptoms.
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, an effect on appetite, and disrupts sleep. Your body is trying to play catch-up, but it takes some time to adjust to the 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.
Beat Jet Lag by Sleeping Better!
Jet lag can really throw you off. Getting a good night's sleep before you travel is key! Our Chilipad Dock Pro bed cooling system can help you fall asleep faster and sleep deeper by keeping you at the perfect temperature (between 55-115º).
What Actually Causes Jet Lag
People of all ages experience jet lag, but it is often more challenging for older adults to adapt to time zones. [3]
Researchers agree that traveling from west to east results in more severe 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 this way shortens your day, conflicting with your natural circadian rhythms that typically extend slightly longer than 24 hours. Flying east is generally considered worse, 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 the new zones can be difficult, resulting in intense symptoms like fatigue, sleep disturbances, and cognitive impairments.
Sleep Study: Roughly 75% of people experience jet lag worse when eastern travel compared to traveling west. [4]
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 it, 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’re not familiar with the effects of jet lag, you might experience grogginess, trouble sleeping, irritability, headaches, or that all-too-familiar brain fog after a long-haul flight.
- 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 it 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, the symptoms improve steadily as the body gets used to the new time zone. [5]
Did You Know: 60-70% of long-haul travelers will experience some form of symptoms and overnight travel causes the most sleep loss. [6]
How to Reduce Jet Lag Before You Travel
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:
- When the symptoms last longer than about a week. Remember, the 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.
Jet Lag FAQs
What is jet lag?
Jet lag happens when you travel across multiple time zones and your body can’t keep up. Your internal clock is still on your old schedule, while the world around you is on a new one. This mismatch can leave you feeling tired, groggy, or out of sync until your body adjusts.
How long does jet lag last?
Symptoms usually improve within a few days, and a common rule of thumb is about 1 day of adjustment per time zone crossed, especially after long-haul flights.
Is jet lag worse flying east or west?
For most people, flying east is worse because you have to fall asleep and wake earlier than your body prefers, while flying west lengthens the day and is generally easier to adapt to.
Can melatonin help jet lag?
Yes, timed low-dose melatonin (usually in the evening at your destination) can help shift your circadian rhythm and reduce jet lag duration and severity when used appropriately.
Does napping help or hurt jet lag?
Short earlier-day naps (20–30 minutes) can ease sleepiness, but long or late naps can make it harder to adjust and may worsen nighttime insomnia from jet lag.
Does hydration actually help jet lag?
Cabin air dehydrates you, worsening fatigue/headaches/sleep issues. Drink water with electrolytes, skip alcohol/caffeine—eases symptoms but doesn't reset your circadian rhythm.
Research & Authoritative References
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Choy, M., & Salbu, R. L.
Jet Lag.
P & T: A Peer-Reviewed Journal for Formulary Management, 36(4), 221–231, 2011.
Source Type: Peer-Reviewed Clinical Review
Key Insight: This comprehensive review explains the biological basis of jet lag, including circadian rhythm misalignment, and evaluates behavioral, pharmacologic, and light-based strategies for prevention and treatment.
View Study
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Ibid.
Source Type: Peer-Reviewed Clinical Review
Key Insight: Further details evidence-based jet lag interventions, including strategic light exposure, melatonin timing, and gradual schedule shifting to accelerate circadian adaptation after travel.
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Choy, Mary, & Salbu, Rebecca L.
Jet Lag: Current and Potential Therapies.
P & T: A Peer-Reviewed Journal for Formulary Management, 36(4), 221–231, 2011.
Source Type: Peer-Reviewed Therapeutic Review
Key Insight: Expands on emerging and future therapies for jet lag, reinforcing the role of circadian biology in treatment selection and travel-related sleep optimization.
View Study
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Eastman, C. I., & Burgess, H. J.
How to Travel the World Without Jet Lag.
Sleep Medicine Clinics, 4(2), 241–255, 2009.
Source Type: Peer-Reviewed Sleep Medicine Review
Key Insight: Presents practical, science-backed travel strategies using light exposure, melatonin, and sleep timing to prevent or significantly reduce jet lag severity.
View Study
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Schwab, R. J.
Circadian Rhythm Sleep Disorders.
Merck Manual Consumer Version, June 2020.
Source Type: Medical Reference Resource
Key Insight: Explains circadian rhythm sleep disorders, including jet lag disorder, and outlines symptoms, causes, and management strategies for circadian misalignment.
View Resource
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Centers for Disease Control and Prevention (CDC).
Jet Lag Disorder.
CDC Yellow Book, April 17, 2025.
Source Type: Government Health Guidance
Key Insight: Provides clinical and traveler-focused guidance on jet lag prevention and management, including light exposure, melatonin use, and travel planning considerations.
View Resource








