Jet lag: Causes, symptoms and prevention

If you've ever traveled across several time zones, there's a good chance you've experienced discomforts when adjusting to the local time. You may be expected to be awake when you're usually asleep in your home-based time zone, or vice versa. This effect is called "jet lag," and it affects millions of travelers.

Jet lag can cause trouble sleeping, daytime tiredness, digestive issues, trouble concentrating and mood changes. This can make it challenging to enjoy activities on your vacation or work well on your business trip. Here you'll learn more about jet lag, including what jet lag means, jet lag remedies and how to avoid jet lag.

Jet lag is a circadian rhythm sleep-wake disorder. Each person has an internal 24-hour clock that tells them when to be awake or feel sleepy. This is your circadian rhythm, and it's affected by sunlight. Your body relies on sunlight to know how much melatonin, a sleep-producing hormone, to make. The body releases more melatonin in the evening and less during the day. Traveling across two or more time zones can disrupt your melatonin production and circadian rhythms. This can affect your ability to sleep or stay alert.

Some studies show that cabin air pressure changes and high altitudes when flying may contribute to symptoms of jet lag, even when you don't travel across time zones. What's more, low humidity levels on airplanes can contribute to dehydration, which may make symptoms of jet lag worse if you don't take in enough water.

Signs of jet lag can include:

• Sleep issues, such as insomnia (trouble falling or staying asleep), waking up too early or intense exhaustion
• Tiredness during the day
• Digestive problems, including loss of appetite, nausea, diarrhea and constipation
• Trouble with concentration and physical and mental performance
• Mood shifts
• A general feeling of discomfort or illness

Jet lag is temporary and can last from a few days to a few weeks. How long it lasts may depend on how many time zones you crossed and in which direction you traveled. Jet lag may be worse when traveling east, when you "lose" time, compared to when traveling west, when you "gain" time. In general, it usually takes about one day per time zone crossed for your body clock to adjust to the local schedule. This means that if you flew across five times zones, it could take around five days for jet lag symptoms to go away.

Other factors can also affect how long jet lag lasts, including your age. Jet lag can affect anyone, but seniors often have a harder time recovering from jet lag compared to younger adults. Still, some people adjust to new time zones relatively easily compared to others for no clear reason.

Taking action before, during and after travel can help you avoid jet lag or reduce its symptoms. Try these tips:

Before your trip:

• Gradually go to bed a few hours earlier (if traveling east) or later (if going west) in the days leading up to travel. This can shift your body's internal clock.
• Get enough sleep leading up to your trip. Feeling tired before travel can worsen jet lag.
• Plan ahead. If you need to make important decisions at your destination, plan to arrive a few days early to give yourself time to get used to the new time zone.

During travel:

• Set your watch to your destination's local time as soon as you board the plane.
• Drink plenty of water.
• Avoid alcohol, caffeine and large meals, which can affect your sleep.
• Sleep on the plane if it's nighttime at your destination. But if it’s daytime at your destination, try not to sleep.

After you arrive:

• Stick to the local schedule. Try not to sleep until nighttime in the new time zone. 
• Eat meals according to local time. 
• If you're very sleepy the first day, nap no longer than 15–20 minutes and be sure it’s more than eight hours before your planned bedtime, so you can sleep at night.
• Spend time in the sun to reset your circadian rhythm.

In most cases, jet lag doesn't require treatment. But if you're a frequent traveler who is often plagued by jet lag symptoms and other remedies haven't helped, talk with your healthcare provider. They may recommend light therapy, medications, or supplements for jet lag, which may improve sleep duration and quality. 

Some research also shows that taking melatonin for jet lag may be helpful. In supplement form, melatonin may help you sleep during times you normally don't. Before taking melatonin, you should discuss with your healthcare provider whether it’s appropriate for you. They can also tell you how much to take and when to take it.

Clinically reviewed and updated May 2023.