How Travel Disrupts Your Sleep — And What to Do About It

You packed your bags, boarded the plane, and arrived at your destination. But your sleep did not travel with you.

It happens to nearly everyone who crosses time zones: you arrive exhausted, but when you finally get to bed, you lie awake for hours. Or you fall asleep easily but wake up at 3 a.m., wide awake and unable to return to sleep. Your body is in one time zone. Your brain is in another.

This is jet lag — a temporary but deeply disruptive condition caused by a mismatch between your body's internal clock and the local time. And the evidence from recent large-scale research shows that travel-related sleep disruption is more pervasive, and takes longer to recover from, than most people realize.

1. The Biology of Jet Lag — Why Your Body Resists the New Time

(1) What Is Jet Lag?

Jet lag is a disruption of circadian rhythms caused by a mismatch between the body's internal clock and the local time, often resulting from travel across time zones or significant shifts in sleep patterns. When you fly across multiple time zones, your internal clock — the circadian rhythm that regulates sleep, hormone secretion, body temperature, and metabolism — suddenly finds itself out of sync with the external light-dark cycle.

Your brain's master clock, located in the suprachiasmatic nucleus, receives signals primarily from light exposure. When you arrive in a new time zone, the sun rises and sets at different times, but your internal clock is still running on your home schedule. This misalignment produces fatigue, insomnia, poor mood, impaired alertness, and gastrointestinal symptoms.

(2) Eastward vs. Westward Travel — Not All Jet Lag Is Equal

The direction you travel matters enormously. Eastward travel — flying against the rotation of the Earth — is consistently more disruptive than westward travel.

A 2025 study analyzing data from 57,240 travelers across 64,847 trips found that sleep disruption was significantly more severe with eastward travel. Why? Because flying east shortens your day, making it harder for your body to advance its internal clock. Westward travel lengthens the day, which is easier for most people to accommodate.

Westward travel allows adjustment at about 1.5 hours per day, whereas eastward travel typically allows adjustment by about 1 hour per day. A flight from New York to London (five time zones east) can take nearly five days to fully recover from; a flight from London to New York (five time zones west) takes just over three days.

(3) The 1.5 Million Nights Study — What the Data Reveals

The largest study of its kind, published in Sleep in 2025, analyzed objective sleep data from wearable devices across 64,847 trips. The findings were striking:

• Sleep disruption begins before you even leave. Sleep duration was curtailed on the night before travel because of early awakening.
• Sleep duration recovers quickly. Sleep duration returned to within approximately 12 minutes of baseline after about two days.
• But sleep timing takes much longer. Changes in sleep timing and sleep architecture were considerably slower to recover, with sleep timing not returning to baseline even after 15 days.

This is a critical insight: you may feel like your sleep has returned to normal because you are sleeping enough hours, but your internal clock is still misaligned for more than two weeks after a long trip.

2. The Cognitive Cost — What Jet Lag Does to Your Brain

Jet lag is not just about feeling tired. It measurably impairs your cognitive performance.

(1) Impaired Reaction Time

A 2025 study presented at the SLEEP annual meeting evaluated the effects of jet lag on psychomotor vigilance — a measure of reaction time and attention. The study found that a simulated jet lag protocol significantly increased reaction times across all participants, with mean reaction time increasing by 25.689ms during the treatment phase.

This may not sound like much, but in real-world terms, a 25-millisecond delay in reaction time can be the difference between avoiding an obstacle and crashing. Even more concerning: the study found that this impairment occurred despite participants receiving treatments designed to reduce jet lag.

(2) Disrupted Sleep Architecture

Even when you are asleep, jet lag is disrupting the quality of your rest. The 1.5 million nights study found that while sleep duration recovered quickly, sleep architecture — the structure and quality of your sleep — remained compromised. You may be sleeping enough hours, but you are not getting the same restorative deep sleep and REM sleep that you would at home.

(3) Mood and Performance

Jet lag also affects mood, mental health, and physical performance. Circadian misalignment is associated with increased anxiety, depressive-like behaviors, and mood alterations. For athletes, jet lag can impair reaction time, accuracy, strength, endurance, and cognitive function.

3. Who Is Most Affected — And When Is It Worse?

(1) Frequent Travelers

Those who fly frequently — business travelers, pilots, flight attendants, and athletes — are at highest risk. A study of a national water polo team found that jet-lag symptoms were greatest on the first day after travel and reduced thereafter, but the severity varied significantly by destination and direction. Eastbound travel produced more severe symptoms than westbound travel.

(2) Older Adults

Aging exacerbates the effects of jet lag. Aging weakens the amplitude of circadian rhythm and shortens its period. Elderly people take a longer time to overcome jet lag. If you are traveling with older family members, be aware that they may need more time to adjust.

(3) More Time Zones, More Disruption

The more time zones you cross, the more severe the disruption. Each additional time zone adds to the mismatch between your internal clock and the local environment.

(4) The Pre-Travel Effect

One of the most surprising findings from the 1.5 million nights study is that sleep disruption begins before you even travel. The anticipation of travel — early morning flights, packing stress, and changes in routine — causes curtailed sleep on the night before departure. This means you are already sleep-deprived before you board the plane.

4. What You Can Do — Evidence-Based Strategies

The good news is that jet lag is manageable. Here are strategies supported by research and expert consensus.

(1) Shift Your Schedule Before You Leave

For travel of up to seven time zones east, move your sleep routine 30 minutes earlier per day starting three days before the trip. Do the opposite if you are traveling west — move your sleep routine later.

Start adjusting mealtimes and bedtime incrementally closer to the schedule of your destination. This gradual shift helps your internal clock begin adapting before you even board the plane.

(2) Use Light Strategically

Light is the most powerful tool for resetting your circadian rhythm.

• For eastward travel: Get bright light exposure in the morning and avoid it in the evening. Wear sunglasses in the morning to delay your internal clock.
• For westward travel: Seek bright light in the evening to help you stay awake longer than you normally would.

(3) Consider Melatonin

Studies have shown that melatonin effectively reduces jet lag symptoms and improves sleep quality. A low dose of melatonin (0.5–3 mg) taken 45 minutes before local bedtime can help you fall asleep in the new time zone.

For eastward travel, take melatonin around local bedtime. For westward travel, only take melatonin if you wake up in the second half of the night to help you fall back asleep. Dr. Vishesh Kapur of the University of Wisconsin Sleep Medicine Center suggests taking low-dose melatonin up to three days before the trip to prevent jet lag.

(4) Set Your Clock Early and Stay Hydrated

As soon as you board the plane, set all your devices to the time of your destination. This simple mental shift helps prepare your body for the new schedule.

Drink plenty of water to combat dehydration, which worsens the effects of jet lag. Avoid alcohol and caffeine, as they promote dehydration and can disturb your sleep.

(5) Nap Strategically

On long flights, take short naps — no longer than 20 minutes — to refresh without interfering with your ability to sleep at your destination. After arrival, avoid the temptation of long naps. If you absolutely need to sleep, take a short nap (no more than 20 minutes) early in the day.

(6) Be Patient

Re-alignment of sleep timing to a new time zone takes significantly longer than most people realize. Even after sleep duration has returned to normal, your internal clock may still be adjusting. Allow yourself time to recover, and consider delaying your return to work or working shorter hours for a few days.

5. The Role of Environment — Supporting Sleep During Travel

Here is what we believe at Moihug: your environment shapes your rest. Not by curing anything, but by removing friction — physical friction, sensory friction, environmental friction — so your body can do what it already knows how to do.

Travel creates environmental friction: unfamiliar beds, strange noises, different temperatures, and the disorienting effect of being in a new place. Your body is already working hard to adjust its internal clock. The least it deserves is a comfortable place to rest.

The Moihug Deep Sleep Pillow is not a treatment for jet lag, circadian rhythm disorders, or any medical condition. It is a long plush body pillow — an environmental comfort tool that can help you create a familiar, comfortable sleep environment no matter where you are.

What it offers:

• Gentle, automatic patting — slow, rhythmic tactile input that may help calm an active nervous system as you wind down in an unfamiliar place
• Wireless audio — stream white noise, nature sounds, or guided relaxation through the pillow to mask unfamiliar sounds and create a consistent pre-sleep environment
• Adjustable warmth — gentle heat up to approximately 110°F for added comfort in unfamiliar climates
• Voice recording — record your own calming messages or positive affirmations to play as part of your travel sleep ritual

Think of it this way: travel disrupts your sleep schedule, your light exposure, your meal times, and your environment. A comfortable, familiar pillow can be one small anchor of consistency in a sea of change — not a cure, but a comfort.

👉 Create a familiar sleep environment wherever you travel. Explore the Moihug Deep Sleep Pillow here.
🔗 https://moihug.com/collections/deepsleep-biometric-comfort-pillow

Summary: Travel Disrupts Your Sleep — But You Can Prepare

You packed your bags, but your sleep did not travel with you. Jet lag is a real, measurable, and deeply disruptive condition caused by the mismatch between your internal clock and the local time.

The evidence from 2025 is clear. A study of 1.5 million nights of sleep data found that while sleep duration recovers within about two days, sleep timing and architecture can take more than two weeks to return to baseline. Eastward travel is more disruptive than westward travel. And sleep disruption begins even before you leave.

But jet lag is manageable. Shift your schedule before you leave. Use light strategically. Consider melatonin. Stay hydrated. Nap strategically. Be patient with your body as it adjusts.

Your body knows how to sleep. It always has. But when you cross time zones, you are asking it to do something difficult — to reset its internal clock. Your job is not to force it. Your job is to create the conditions — the right light exposure, the right schedule, the right environment — that let it do what it already knows how to do.

Start with one change on your next trip. Not everything. Just one. Notice what changes.

References

1. Willoughby AR, Vallat R, Ong JL, Chee MWL. Insights about travel-related sleep disruption from 1.5 million nights of data. Sleep. 2025;48(7):zsaf077.
2. Bartel H, Mak N, Youngstedt S, Patel S. 0873 The Effects of Jet Lag and Circadian Acclimation of Performance, Sleep, and 6-sulfatoxymelatonin on Psychomotor Vigilance Reaction Times. Sleep. 2025;48(Supplement_1):A379-A380.
3. Boutrin MC, et al. Improved jet lag recovery is associated with a weaker molecular biological clock response around the time of expected activity onset. Frontiers in Behavioral Neuroscience. 2025;19:1535124.
4. Botonis PG, et al. Effects of Consecutive Long-Haul Travel on Jet-Lag Symptoms: Case Study of a National Water Polo Team Preparing for World-Class Events. International Journal of Sports Physiology and Performance. 2025;21(2):267-273.
5. Xu YX, et al. Association between behavioral jet lag with subjective and objective circadian rhythm among Chinese young adults. Social Science & Medicine. 2025;366:117689.
6. Johns Hopkins University. How to prevent jet lag from ruining your vacation. Wellbeing. 2024.
7. Equinox Hotels. Dr. Matt Walker‘s Strategies to Combat Jet Lag. 2024.
8. Harvard Health Publishing. How to avoid jet lag: Tips for staying alert when you travel. 2025.