Clinically reviewed by Dr. Ponlawat Pitsuwan, Physician, Doctor Bangkok. Last reviewed: July 2026
Jet lag after a long-haul flight to Bangkok usually lasts one day per time zone crossed. For most European travellers that means up to a week. For North Americans, potentially longer. Light exposure, consistent sleep timing, and low-dose melatonin are the most evidence-backed tools for recovery. If your symptoms include fever, leg swelling, chest pain, or fatigue that is not improving after two weeks, stop self-managing and see a doctor.
You have just landed at Suvarnabhumi. You are exhausted, slightly confused about what time it is, and wondering whether you will feel normal again before your trip is half over. If you are reading this from your hotel room at 3am Bangkok time, wide awake despite being on your feet for 30 hours, this is for you.
Jet lag is your body’s internal clock fighting the new time zone. Bangkok sits at GMT+7, which puts it six to seven hours ahead of Western Europe, eleven to twelve ahead of the US East Coast, and fourteen to fifteen ahead of the US West Coast. Australians on the east coast have it easiest at around three hours. The bigger the gap, the longer the reset.
Jet lag, travel fatigue, and burnout: three different problems
Most people use these words interchangeably. They are not the same thing, and the difference matters for how you recover.
Jet lag is a circadian rhythm problem. Your body’s internal clock is still set to home. It is telling you to sleep at noon and be wide awake at 2am.
Travel fatigue is different. It is the physical and mental exhaustion from the journey itself: sitting for fifteen hours, poor sleep on the plane, dehydration, bad food, airport stress. One good night’s sleep often clears most of it.
Burnout goes deeper. It builds over weeks or months of constant travel, relocation stress, or living out of a suitcase. It does not go away after a good sleep. If you arrive in Bangkok already running on empty, what you are dealing with is not jet lag. It needs a different conversation.
How bad will your jet lag actually be?
The rough rule is one day of recovery for every time zone you cross. That is not a guarantee, but it is a useful anchor.
Flying west is generally easier than flying east. Bangkok to London is westward. London to Bangkok is eastward, and eastward travel disrupts sleep more because it asks your body to go to sleep before it is ready.
Your natural sleep preference also plays a role. If you are a night owl at home, adjusting to an early Bangkok morning schedule will be harder. Morning people tend to adapt to eastward travel more quickly.
One pattern I see often: patients who arrive from Europe feel reasonable on day one because the adrenaline of arrival carries them. Day two or three is when it hits hardest. Plan for it.
What actually helps: the evidence-based short list
Get into natural daylight as soon as you can each morning. Even thirty minutes outside before 9am makes a real difference to how quickly your body resets.
Melatonin is the most useful sleep tool you have. Evidence supports low doses, somewhere between 0.5 and 3 milligrams, taken close to your target bedtime in Bangkok, not your home bedtime. Timing matters more than the dose. One important note: melatonin is prescription-only in Thailand, not sold over the counter like it is in the US or UK. Bring a personal supply or speak to a doctor here who can prescribe it.
Avoid long naps in the afternoon. A short rest of 20 to 30 minutes is fine. Sleeping for two hours at 4pm will push your clock in the wrong direction.
Stay hydrated. Most people land already dehydrated without realising it. Dehydration makes every jet lag symptom feel worse. Skip the alcohol on the flight and the first couple of nights. It actually reduces sleep quality and slows your circadian adjustment, despite what it feels like.
Travel fatigue and burnout in Bangkok: when rest is not enough
Some patients come in a week after landing still feeling hollowed out. They have slept well, eaten well, and done everything right. Jet lag should be resolving, but it is not.
A few things can look like jet lag but are not. Travel stress suppresses your immune system. The first week in a new city is when people are most likely to pick up a bug. A mild fever, a sore throat, or an upset stomach layered on top of jet lag can be hard to separate from each other.
There is also a more serious risk worth naming: deep vein thrombosis, or DVT. This is a blood clot that can form in the legs during long flights. Symptoms include a swollen, warm, or painful calf, usually on one side. This is not jet lag. This needs same-day medical assessment. Do not wait it out.
If you have been in Bangkok for more than two weeks and still feel deeply exhausted, foggy, or low in a way that rest is not touching, that is burnout territory. It will not resolve with melatonin and blackout curtains. What helps is a proper medical review to rule out anything physical, and then a realistic plan to slow down.
The most common story I hear from long-term expats at Doctor Bangkok is this: "I thought I just had jet lag, then I thought I was just tired, and now it has been three months." Do not let it get that far.
An IV vitamin drip is one option some patients find helpful during the first few days. It replenishes fluids and key nutrients directly, which can feel like a genuine reset when you are depleted from travel. It is not a cure for jet lag, but for severe fatigue and dehydration it provides real relief.
What to do if you fall ill on a long-haul flight to Bangkok
This happens more than people expect. Cabin air is very dry, and you are sitting still for many hours. These conditions can trigger headaches, nausea, and dizziness.
If you feel faint, tell the cabin crew immediately. They are trained for this. Every commercial aircraft carries a medical kit. Flight crew can give you basic first aid and oxygen, and they can contact a ground medical team by radio. If symptoms are serious enough, the pilot may divert the flight.
If you land at Suvarnabhumi feeling unwell, there is a medical centre in the arrivals terminal. For mild symptoms like nausea, a headache, or dizziness, use it or rest and monitor. For anything more serious, including chest pain, difficulty breathing, confusion, or a leg that is swollen and painful, get to a hospital emergency room without delay.
For symptoms that are concerning but not emergencies, Doctor Bangkok is centrally located and BTS accessible. A same-day consultation with an English-speaking physician is available without a referral.
If you have a significant medical condition and you are planning a long flight to Bangkok, a fit-to-fly assessment before you travel is worth doing. It identifies risks in advance and means you land with a plan, not a problem.
Feeling rough after your flight and not sure if it is jet lag, something more, or both? Doctor Bangkok offers same-day general medical consultations with English-speaking physicians, IV drip therapy for post-travel recovery, and full assessment for any symptoms that are not resolving. Centrally located in Bangkok and BTS accessible. No referral needed. Book at doctorbangkok.co.th.
Frequently asked questions
How long should jet lag last after flying to Bangkok, and when is it taking too long?
The general guide is one day of recovery per time zone crossed. For European travellers that is up to a week; for North Americans it can be longer. If fatigue, sleep disruption, or brain fog is still significant after two weeks, or if you develop fever, leg swelling, or chest tightness, stop self-managing and get a medical assessment.
Is melatonin available in Thailand, and what dose should I take for jet lag?
Melatonin is prescription-only in Thailand and not sold over the counter. Bring your own supply from home, or see a doctor in Bangkok who can prescribe it. Evidence supports doses of 0.5 to 3 milligrams taken at your target bedtime in the new time zone, not whenever you feel sleepy.
What is the difference between jet lag and travel fatigue?
Jet lag is a circadian rhythm disruption caused by crossing time zones. Travel fatigue is physical and mental exhaustion from the journey itself and often clears after one good sleep. If rest alone is not working after several days, something else may be going on.
I felt unwell on my flight to Bangkok. What should I do when I land at Suvarnabhumi?
There is a medical centre in the Suvarnabhumi arrivals terminal for mild symptoms. For anything serious, including chest pain, breathing difficulty, leg swelling, high fever, or confusion, go straight to a hospital emergency department. For symptoms that are not emergencies but need a doctor the same day, Doctor Bangkok is accessible by BTS with no referral needed.
Can a Bangkok doctor prescribe something to help me sleep and recover faster?
Yes. A GP consultation can result in a short prescription for melatonin, a mild sleep aid, or anti-nausea medication where appropriate. Same-day appointments are available at Doctor Bangkok. Self-medicating with sleeping pills brought from home carries real risks, especially combined with alcohol or disrupted meal timing in a new time zone.
Is flying east to Bangkok worse for jet lag than flying west?
Yes, for most people. Eastward travel asks your body to sleep earlier than its current setting, which is harder to force than staying up later. Returning from Bangkok to Europe is generally easier to recover from than the outbound journey for this reason.
Dr. Ponlawat Pitsuwan
Physician, Doctor Bangkok
a private medical clinic in central Bangkok. He sees expats, residents, and medical tourists for general medical consultations, post-travel illness, and recovery care including IV therapy. His focus is straightforward, evidence-based care delivered in plain language.
Dr. Ponlawat Pitsuwan is a physician at Doctor Bangkok, a private clinic in central Bangkok. He sees expats, residents, and medical tourists for general medicine, wellness consultations, and IV therapy. His focus is straightforward, evidence-based care delivered in plain language.
