How to Avoid Jet Lag: What Actually Helps

Why does jet lag happen?

Your circadian rhythm is a roughly 24-hour internal clock driven largely by light signals received through your eyes. It coordinates when you feel sleepy, when you are alert, when your core body temperature rises and falls, and when digestive hormones are released.

Rapid travel across multiple time zones moves your local clock faster than your body can follow. Eastward travel is generally harder than westward because advancing the clock — moving it earlier — is more difficult for most people's biology than delaying it. The more time zones you cross, the more pronounced the mismatch 1Ref 1Centers for Disease Control and Prevention (2023).CDC Yellow Book 2024: Health Information for International Travel.Jet lag biology, eastward vs. westward difficulty, light exposure and sleep strategies for travelers, alcohol and caffeine effects in-flight.

Should you shift your schedule before you fly?

If your trip allows a few days of preparation, gradually shifting your sleep and wake times toward your destination's schedule can reduce severity:

• Eastward travel: go to bed and wake up one hour earlier each day for two to three days before departure. Get bright light in the morning.
• Westward travel: shift sleep and wake times later. Get bright light in the evening.

During the flight, set your watch to destination time right away and eat and sleep according to that clock if possible. Even one hour of pre-adaptation per day makes a measurable difference 1Ref 1Centers for Disease Control and Prevention (2023).CDC Yellow Book 2024: Health Information for International Travel.Jet lag biology, eastward vs. westward difficulty, light exposure and sleep strategies for travelers, alcohol and caffeine effects in-flight.

Is light exposure really the most powerful tool?

Yes. Light is the primary cue that resets the circadian clock 1Ref 1Centers for Disease Control and Prevention (2023).CDC Yellow Book 2024: Health Information for International Travel.Jet lag biology, eastward vs. westward difficulty, light exposure and sleep strategies for travelers, alcohol and caffeine effects in-flight. At your destination:

• Eastward travel: seek bright outdoor light in the morning local time and avoid bright light in the late evening.
• Westward travel: seek light in the early evening local time.

Sunlight is most effective; a bright indoor environment or a light therapy box is a reasonable substitute in poor weather. Avoiding light at the wrong time is equally important — evening screen use delays melatonin release and can accidentally reset your schedule in the wrong direction 2Ref 2Chang AM, Aeschbach D, Duffy JF, Czeisler CA (2015).Evening Use of Light-Emitting eReaders Negatively Affects Sleep, Circadian Timing, and Next-Morning Alertness.Evening light exposure delays circadian timing and melatonin release — relevant to avoiding screen use at the wrong time when managing jet lag. Blue-light-blocking glasses or avoiding bright screens late in the evening can help.

When and how should you use melatonin for jet lag?

Melatonin is a hormone your brain naturally releases as darkness falls, signaling sleep onset. Taken at the right time — not just any time before bed — low doses can help shift your rhythm toward the destination time zone.

A Cochrane review found that melatonin is effective for preventing and reducing jet lag when taken at the appropriate phase of the new time zone 3Ref 3Herxheimer A, Petrie KJ (2002).Melatonin for the Prevention and Treatment of Jet Lag.Melatonin is effective for preventing and reducing jet lag when taken at the appropriate circadian phase; timing matters more than dose. For eastward travel, taking a small dose at your destination's target bedtime is the typical approach. For westward travel, the evidence is less clear.

Timing matters more than dose. Taking it at the wrong phase of your rhythm can worsen rather than help. Doses in commercially available products are often higher than what has been studied for circadian shifting — more is not necessarily better.

A clinician or pharmacist can advise on appropriate timing for your specific itinerary, especially if you take other medications or have health conditions.

What should you do on the plane and at your destination?

On the plane: - Stay well hydrated — aircraft cabin air is very dry, and dehydration worsens fatigue. - Avoid or limit alcohol and excess caffeine, as both disrupt sleep quality 1Ref 1Centers for Disease Control and Prevention (2023).CDC Yellow Book 2024: Health Information for International Travel.Jet lag biology, eastward vs. westward difficulty, light exposure and sleep strategies for travelers, alcohol and caffeine effects in-flight. - Sleep only when it aligns with nighttime at your destination; use an eye mask and earplugs or noise-canceling headphones.

On arrival: - Resist the urge to nap if it is daytime at your destination — push through to local bedtime if possible to anchor your new schedule. - Get outside for a short walk; the combination of natural light and physical activity helps. - Give yourself two to four days before important meetings or demanding activities if your schedule allows.

Does age or other health conditions affect jet lag recovery?

Age: Older adults often find jet lag more disruptive and recovery slower. The circadian clock becomes less flexible with age, making pre-adaptation and careful light management especially worthwhile.

Sleep disorders: People with insomnia or obstructive sleep apnea may experience more severe disruption and should discuss travel strategies with their clinician before a long trip.

Pregnancy: Travel fatigue and circadian disruption are often amplified in pregnancy. Melatonin supplement use during pregnancy should be discussed with a clinician before use.

Shift workers: People already accustomed to disrupted schedules may adapt differently — sometimes more easily, sometimes less, depending on their baseline rhythm.