You can train for the walking. You cannot train for the altitude. Above about 3,000 m the air holds less oxygen, and no amount of fitness changes that — what changes it is time, and giving your body enough of it is the single most important thing a well-run trek does. So we design the whole journey around altitude rather than treating it as an afterthought. Here is how, in plain terms.
Why altitude is the real challenge
At sea level the air you breathe is dense with oxygen. As you climb, the air thins, and each breath delivers less. Your body responds — it breathes faster, makes more red blood cells, adjusts over days — but that adjustment takes time. Push up too fast and the adjustment cannot keep pace, and you feel it: headache, poor sleep, loss of appetite, a general flatness. That is altitude sickness in its mild form, and left unheeded it can become serious.
The good news is that it is almost entirely preventable. The rule that prevents it is simple and old: climb high, sleep low, and go slowly. Everything we do at altitude is a way of holding to that rule even when the summit is tempting and the schedule is tight.
Acclimatisation, built into the route
Acclimatisation is not something you do at the end. It is designed into the shape of the walk itself — into how many metres you gain in a day and where you sleep at night.
This is why our itineraries are longer than the rushed versions you will see elsewhere. Our Everest Base Camp trek is twelve days, not ten, precisely so acclimatisation is real. It builds in dedicated rest days — an active day in Namche, another in Dingboche — placed exactly where the body needs them most before the higher stages. The Annapurna Circuit acclimatises for two nights at Manang before the Thorong La. The Manaslu Circuit takes two full acclimatisation days, at Sama Gaon and Samdo, before the Larkya La.
Those extra days are not slack in the schedule. They are the schedule doing its most important work.
Why rest days work
A rest day on our treks is rarely a day spent lying down. It is what mountaineers call an active rest day: you climb a few hundred metres higher during the day — up to the Everest View Hotel above Namche, say, or toward the Ice Lake above Manang — and then come back down to sleep at the lower elevation.
That is climb high, sleep low in miniature. The daytime climb signals your body to adapt to the greater height; sleeping lower lets it recover and consolidate that adaptation overnight. Do this for a day at the right elevation and you arrive at the next high camp measurably better prepared. It feels like a gentle day. It is doing a great deal.
What SpO2 is, and why we take it twice a day
SpO2 is the percentage of your blood's haemoglobin that is carrying oxygen. A small clip on your fingertip measures it painlessly in a few seconds. At sea level a healthy reading is around 98 to 100 per cent; at altitude it drops, and that is expected — the number tells us how well your body is coping with the thinner air, and it tells us early, before you necessarily feel anything.
That early warning is the point. From day three onward on Everest Base Camp, and daily on Annapurna and Manaslu, your guide takes an SpO2 reading twice a day and notes it. A single low number is not alarming on its own — everyone's varies — but a trend that keeps falling, or a reading that drops below our safe threshold, tells us to slow down, rest, or descend before a problem develops rather than after. It turns altitude from something we react to into something we can see coming.
Oxygen above 4,000 m, and a guide trained to use it
On every stage above 4,000 m we carry supplementary oxygen. It is a contingency, not something you will normally use — most travellers never need it — but it is there, on the trail, every day you are high, rather than a phone call away. Your senior guide is wilderness-medicine trained and knows how to use it, when to use it, and, just as importantly, when the right call is simply to turn around.
That last point is the quiet backbone of the whole approach. If a reading or a symptom says stop, we stop. If it says descend, we descend. No summit, no view, and no schedule is worth pushing a body past what it can safely do that day — and part of what you are paying for is a team with the judgement and the authority to make that call without hesitation.
Read more, or ask us
This note is the short version. Our safety page sets out the full protocol — the training our guides carry, the monitoring, the contingencies — in more detail, and it is worth reading before any high walk.
And if you are new to altitude and it worries you, say so. It is one of the most common and most sensible things travellers raise, and answering it honestly is a large part of what the first conversation is for. Tell us your history and the trek you are considering, and we will tell you plainly how we would look after you on it. Begin a conversation whenever you are ready.