In brief:
- Jet lag occurs when your internal clock doesn’t match the local time at your destination, and symptoms last about one day for each time zone crossed.
- Flying east is generally harder than flying west, because the body’s natural circadian rhythm is slightly longer than 24 hours.
- Melatonin (0.5–3 mg) taken at destination bedtime has been shown to reduce jet lag symptoms after five or more time zones.
- Strategic use of light and adjusting your sleep schedule are more effective than simply resting or drinking coffee.
How does jet lag occur and why does it disrupt sleep?
Jet lag is a circadian rhythm disruption that occurs when your internal biological clock is out of sync with local time at your destination. The biological clock regulates the sleep-wake cycle, fluctuations in body temperature and the release of hormones — above all melatonin, which the pineal gland produces as darkness falls (Sack, 2010). When you fly across several time zones, your internal clock remains out of sync with the new reality: your body needs time to adjust its rhythm to the new light-dark cycle.
Typical symptoms include daytime sleepiness, insomnia at night, reduced concentration, irritability and digestive problems. Studies show that flying east is generally harder than flying west, because the human circadian rhythm is slightly longer than 24 hours and adapts more easily to a lengthened day than to a shortened one (Waterhouse et al., 2007).
Besides jet lag, sitting still during long flights can cause physical discomfort — for example, nerve pain in the back, which is especially common on transatlantic and Asia-bound routes and which moving regularly during flights can help ease.
How long does jet lag last?
As a general rule, adaptation takes roughly one day for each time zone crossed (Eastman & Burgess, 2009). So a 7-hour shift — for example, on a return trip between Tallinn and New York — means an adaptation period of up to a week. It is important to understand that faster is not always better or healthy — you cannot force the body’s circadian rhythm to adapt faster than biological processes allow, and pushing a sleep schedule too aggressively can make things worse.
For most travelers, jet lag is temporary. If symptoms — such as insomnia, anxiety and reduced concentration — last for more than two weeks, it is worth seeing a doctor. The WHO sleep health guidelines emphasize that long-term disruption of the circadian rhythm can affect immune function, mood and metabolic health, which is why more serious cases should be taken seriously.
What methods can you use to overcome jet lag?
The most effective strategies fall into three main categories.
Managing light exposure
Light is the main synchronizer of the circadian rhythm. When flying east, avoid morning light for the first few days and seek out evening light instead; when flying west, do the opposite. Strategic light exposure can speed up adaptation by up to 1–2 days, and it is free and has no side effects (Eastman & Burgess, 2009).
Adjusting your sleep schedule
Before a long trip, try shifting your bedtime and wake-up time by 1–2 hours toward the destination’s time. Once you arrive, avoid long daytime naps, as they slow the adaptation of the circadian rhythm. A short 10–20-minute nap is recommended: it eases fatigue without disrupting adaptation.
Physical activity and nutrition
Moderate movement at your destination — for example, a walk in the fresh air — helps speed up the synchronization of the circadian rhythm. For athletes who want to get back into training shape and keep progressing quickly after a trip, it is important to combine physical activity with the right light during daylight hours at the destination. Amino acids have also been studied for supporting recovery — glutamine helps you recover faster from intense physical training load, which is especially relevant for athletes who need to be in training shape quickly after a long trip.
Does melatonin help with jet lag?
Melatonin is the most extensively studied aid against jet lag. A Cochrane systematic review that covered more than 400 study participants, both flight crew and passengers, found that melatonin (0.5–5 mg) taken at destination bedtime significantly reduces jet lag symptoms after crossing five or more time zones (Herxheimer & Petrie, 2002). The recommended dose is 0.5–3 mg taken 30 minutes before bedtime at your destination for the first 2–4 nights. Higher doses (5 mg and above) are not more effective, but they may cause headaches and daytime sleepiness (Herxheimer & Petrie, 2002).
Melatonin is sold in Estonia as an over-the-counter product. Before using it, it is worth consulting a doctor, especially if you take other medications or have chronic conditions.
References
- Sack RL (2010). Jet lag. N Engl J Med. 362(5):440–447. PMID: 20110528
- Waterhouse J, Reilly T, Atkinson G, Edwards B (2007). Jet lag: trends and coping strategies. Lancet. 369(9567):1117–1129. PMID: 17382306
- Eastman CI, Burgess HJ (2009). How to travel the world without jet lag. Sleep Med Clin. 4(2):241–255. PMID: 20357988
- Herxheimer A, Petrie KJ (2002). Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev. CD001520. PMID: 12076414
Frequently asked questions
Is jet lag a serious illness?
No, jet lag is a temporary circadian rhythm disruption that usually passes within a few days. It does not require medical treatment, but it can significantly affect performance and well-being during the first days of a trip.
How can you ease jet lag on the plane?
Drink enough water, avoid alcohol and caffeine, move regularly, set your watch to destination time and try to sleep according to the destination’s night.
Is flying east harder than flying west?
Yes, for most people flying east is harder, because the body’s circadian rhythm is slightly longer than 24 hours and adapts more easily to a lengthened day.
When should you take melatonin for jet lag?
Take 0.5–3 mg of melatonin 30 minutes before bedtime at your destination for the first 2–4 nights after arrival. Do not exceed the recommended dose.
Does drinking coffee help with jet lag?
Caffeine can temporarily ease daytime fatigue, but it does not cure jet lag. Late caffeine can make it harder to fall asleep at night and slow down adaptation.
Come and train! ArtGym
