Every year a number of travellers from Gujarat fly into Leh, step off the aircraft at well over three thousand metres, spend the afternoon sightseeing because they feel perfectly fine, and are seriously unwell by midnight. The same thing happens on the trail to Everest Base Camp, on the way up to Kailash, and to visitors who land in Cusco and head straight for Machu Picchu. It is the most predictable illness in travel and one of the most consistently underestimated, largely because of a belief that being young, fit or a regular at the gym provides some protection. It does not. Fitness has almost no bearing on who gets altitude sickness.
What matters is how high you go, how fast you get there, and where you sleep. This guide sets out how acute mountain sickness works, the ascent rules that prevent it, the two conditions that turn it from an unpleasant headache into an emergency, and the insurance question that catches Indian travellers out more than any other — because the helicopter that comes for you in the Himalaya is not free and is frequently not covered.
What altitude actually does to you
The proportion of oxygen in the air does not change as you climb — what falls is the air pressure, so each breath delivers fewer oxygen molecules to your blood. At around 3,500 metres you are taking in roughly two-thirds of the oxygen available at sea level; by 5,000 metres it is closer to half. Your body responds by breathing faster and deeper, raising your heart rate and, over days, producing more red blood cells. That adjustment is acclimatisation, and it takes time your itinerary has to allow for.
Acute mountain sickness is what happens when you outrun that adjustment. The classic presentation is a headache plus some combination of nausea, loss of appetite, fatigue out of proportion to what you have done, dizziness and poor sleep. A useful and slightly unromantic rule of thumb: if you have a headache above 2,500 metres and you cannot confidently explain it some other way, treat it as altitude until proven otherwise. Symptoms often appear six to twelve hours after arriving at a new height, which is exactly why the traveller who feels fine on landing in Leh feels dreadful that night.
The ascent rules that actually prevent it
Above roughly 3,000 metres, the widely taught guidance is to raise your sleeping altitude by no more than about 300 to 500 metres per night, and to build in a full rest day for roughly every 1,000 metres gained. The phrase mountaineers use is climb high, sleep low — walking to a higher point during the day helps acclimatisation, provided you come back down to sleep. What your body adapts to is the altitude at which you sleep, not the highest point you touched.
The awkward truth is that flying into a high airport breaks these rules before your trip begins, because you gain in ninety minutes what a walker would take a week to gain. The remedy is a deliberately empty first day: arrive, go to your hotel, rest, drink water, eat lightly, and do not schedule a monastery tour for that afternoon however tempting the light is. Two quiet days at the start of a Ladakh trip buy you the whole rest of the holiday, and travellers who skip them frequently lose more than two days to feeling ill. If you are planning that route, our Ladakh road trip guide for travellers from Gujarat sets out an itinerary with the acclimatisation built in rather than bolted on.
The two conditions that are emergencies
Ordinary acute mountain sickness is miserable but not dangerous if you stop ascending. Two less common progressions are genuinely life-threatening and both are treated the same way: descend immediately. High altitude pulmonary oedema involves fluid in the lungs — breathlessness at rest rather than on exertion, a persistent cough, sometimes frothy sputum, extreme fatigue and a blue tinge to the lips. High altitude cerebral oedema involves swelling in the brain — confusion, unusual behaviour, severe headache unrelieved by painkillers, and a loss of coordination that shows up as an inability to walk a straight line heel to toe.
Both can develop within hours and both can be fatal. Descent of even 500 to 1,000 metres often produces dramatic improvement, and descent should never be postponed until morning for the sake of convenience. Supplemental oxygen and a portable hyperbaric bag buy time; they do not replace going down. The one piece of judgement worth rehearsing before you travel is this: in a group, the person who is unwell is often the last to recognise it, particularly with cerebral symptoms. Agree in advance that anyone can call it for anyone else, and that nobody has to justify a decision to descend.
Medication: what helps, what does not, and what to ask your doctor
Acetazolamide is the drug most commonly prescribed to speed acclimatisation, and it is taken preventively starting a day or so before ascent rather than as a rescue treatment. It is a prescription medicine with real side effects — tingling in the fingers, frequent urination, an odd metallic taste, and it is unsuitable for people with certain allergies and conditions — so the conversation belongs with your doctor, well before departure, not with a pharmacy at the trailhead. Dexamethasone and nifedipine appear in emergency protocols for the two severe conditions above, and are for use under medical direction rather than self-prescription.
Simple paracetamol or ibuprofen handles an altitude headache reasonably well. Alcohol and sedatives are best avoided in the first days at height, because both suppress breathing during sleep, which is precisely when your oxygen levels are lowest. Drink water steadily, though do not overdo it to the point of drinking litres beyond thirst. Carry everything in the cabin in labelled original packaging with a doctor's letter — our guide to carrying prescription medicines across international borders covers the documentation that keeps security and customs straightforward. Nothing in this article is medical advice, and anyone with heart or lung disease, sickle cell trait, diabetes, or a pregnancy should take the question to their own doctor before booking a high-altitude trip at all.
The insurance gap that catches Indian travellers out
This is the part most people discover too late. A standard travel insurance policy frequently excludes trekking above a stated altitude — often somewhere between 2,500 and 4,000 metres depending on the insurer — and excludes mountaineering and high-altitude activities entirely unless a specific rider is purchased. A policy that covers your flight delay and your lost bag may pay nothing at all towards a helicopter evacuation from a Himalayan valley, and those evacuations are expensive enough to reshape a family's finances.
So read the altitude limit in the policy wording, not the brochure, and tell the insurer the maximum height on your itinerary and the activities planned. Confirm in writing that emergency evacuation and repatriation are included at that altitude, and check whether the insurer requires you to call them before authorising a rescue, which is impractical in a valley with no signal and is worth knowing about in advance. Our travel insurance guide for Indian travellers explains what the different covers do, and it is worth reading before you buy rather than after.
Where this bites: the trips Gujarati travellers actually take
Ladakh is the most common and the most underestimated, because you fly straight into it. The Kailash Mansarovar yatra is the most demanding, involving sustained time above 4,500 metres and a pass higher still, with limited evacuation options — our Kailash Mansarovar yatra guide from Gujarat covers the preparation that route genuinely requires. Nepal trekking routes are generally kinder because you walk up, which builds acclimatisation naturally, though the Everest region still needs its scheduled rest days.
Further afield, Peru surprises people: Cusco sits higher than many Himalayan hill stations, and the standard advice there is to spend the first nights lower in the Sacred Valley before returning up — our Machu Picchu travel guide from India sets out that sequence. Bhutan's passes are high even when the towns are not, as our Bhutan travel guide notes, and Kilimanjaro remains a notorious case precisely because it needs no technical skill, which encourages people to rush it. For older travellers on any of these, pace matters more than anything else, and our guide to travelling abroad with senior citizens and parents is a useful companion to this one.
Eating, drinking and sleeping at height
Appetite commonly falls at altitude just as your energy needs rise, so eat regularly even when you do not feel like it, favouring carbohydrates, which are slightly easier for the body to process on less oxygen. Dehydration is easy at height because the air is dry and you breathe harder, and its symptoms overlap confusingly with mild altitude sickness. Water safety matters here too, particularly on tea-house routes — our notes on food and water safety abroad apply squarely to Himalayan trekking, where a stomach upset and dehydration at 4,000 metres is a far worse combination than either alone.
Expect broken sleep for the first nights. Periodic breathing, where your breath pauses and then catches up, is common at altitude and alarming the first time you notice it in yourself or a companion, but is not in itself dangerous. What matters is how you are during the day: steadily improving is the normal trajectory, and steadily worsening is the signal to stop going up.
Frequently asked questions
Does being fit protect me? No. Fitness helps you enjoy the walking, but it does not predict who gets altitude sickness, and fit young travellers are over-represented among casualties precisely because they ascend faster and are slower to admit they feel unwell.
If I was fine at altitude before, am I safe now? Not necessarily. Susceptibility is reasonably consistent for a given person but not guaranteed, and a faster ascent profile on a new trip can produce symptoms you have never had before. Previous success is not a licence to skip rest days.
Do children get altitude sickness? Yes, and they can be harder to assess because a young child cannot describe a headache well and simply becomes irritable, clingy or off their food. Ascend more conservatively with children and have a lower threshold for descending.
What about oxygen cylinders sold in hill towns? Small canisters give brief symptomatic relief and can be useful, but they are not a treatment and they are certainly not a reason to keep climbing. The treatment for serious altitude illness is descent.
Planned properly, a high-altitude trip is one of the most rewarding journeys available — and the planning is mostly a matter of putting rest days in the right places and buying the right insurance. Explera Vacations builds Ladakh, Nepal, Bhutan and South America itineraries from Surat with acclimatisation designed in rather than squeezed out, and we will tell you plainly when a schedule you have seen advertised is too fast to be sensible. Send your dates and the group's ages to our team through the contact page, or look through our tour packages from Surat and we will build the pacing around the people actually travelling.
