Annapurna Circuit: altitude profile and acclimatisation

Those who want to tackle the Annapurna Circuit properly need to understand two things above all: the altitude profile and the pace at which your body can adapt. The route often feels logically constructed, but the tipping point is high. From Manang, you already sleep around 3,540 metres and then you slide on in short order to Yak Kharka, Thorong Phedi and finally Thorong La at 5,416 metres. Those who take this too lightly increase the chances of headaches, poor sleep, performance loss and, at worst, serious altitude problems.

The good news is that the Annapurna Circuit is precisely another trek that can be planned well. With a smart rest day in Manang, a controlled build-up and honest monitoring of symptoms, the route is perfectly feasible for many fit trekkers. Those who want to delve extra deeply into acclimatising at home for mountain expeditions, moreover, often leaves with more margin.

The Annapurna Circuit altitude profile at a glance

Today, the exact route varies more often than before. Some trekkers start lower, others take a jeep up to Tal, Dharapani or even higher. Still, the physiological logic remains the same: below about 3,000 metres you mainly build up general load, but from about 3,000 to 3,500 metres acclimatisation becomes really decisive. Those wanting more background on the relationship between altitude and oxygen can also check out our height to oxygen table view.

This profile immediately explains why the trek feels surprisingly tough for some. Not because the altimeters per day are absurd, but because above Manang you spend several nights at a serious sleeping altitude and then go in one push to a pass above 5,400 metres.

Why exactly Manang is the key place

Many routes have a rest day. On the Annapurna Circuit, Manang is where that rest day really makes a difference. You sleep there around 3,540 metres, so high enough to already experience considerable hypoxic stress, but still low enough that with an extra night you often recover noticeably. At the same time, it is the ideal base for a short dayhike higher up and then sleeping at the same altitude again.

This fits perfectly with the well-known principle of climb high, sleep low. So an acclimatisation day in Manang does not mean sitting still. On the contrary. The best interpretation is often a quiet hike to a higher point, for instance towards Gangapurna or Ice Lake, after which you return to sleep in Manang again. By contrast, those who skip Manang or only stay for a very short time often make the jump to the zone above 4,000 metres more aggressive than is wise.

How to smartly build your acclimatisation on the Annapurna Circuit

The golden rule remains simple: watch your sleeping altitude. Above 3,000 metres, you don't normally want to raise it too quickly. The CDC recommends that above 3,000 metres, you should preferably increase your sleeping altitude by no more than about 500 metres per day and build in extra acclimatisation time for every additional 1,000 metres of ascent. That makes the build-up Pisang - Manang - rest day - Yak Kharka - Thorong Phedi logical, as long as you keep up honest monitoring along the way.

For many trekkers, this is also the time to realise again that fitness and acclimatisation are not the same thing. A strong runner or cyclist can feel great conditionally but still get altitude sickness. Those who are more susceptible to altitude sickness would do well to also learn about preventing altitude sickness and in the question of what a normal acclimatisation rate per 1,000 metres actually means.

The most common misunderstandings

An additional nuance is High Camp. Some trekkers choose to sleep even higher above Thorong Phedi to make the pass day shorter. This may seem logistically appealing, but physiologically it is not automatically better. You gain time on the climb, but you shift your sleep to thinner air, often on a night when your sleep quality is under pressure anyway. For many people, Thorong Phedi is therefore the safer choice, especially if headaches, poor appetite or restless sleep are already present.

This is how you monitor this lens

A good acclimatisation plan is not just an itinerary. It is also an observation plan. Therefore, use the same four lenses daily: symptoms, sleep, recovery and trend. If you bring a saturation gauge, it is best to use it as a trend instrument and not as an absolute truth. At altitude, oxygen levels drop even in healthy travellers and, especially during sleep, the load can increase markedly.

The most useful decision rule is simple. Mild, stable symptoms may fit with acclimatisation. Clearly worsening complaints at the same altitude are an alarm signal. And complaints that get worse as you go higher are a reason not to ascend further. Those who want to understand more about what a saturation reading does and does not say can also read our explanation of oxygen saturation at altitude read.

When an abbreviated schedule becomes too aggressive

The Annapurna Circuit is often walked shorter these days than it used to be. This makes sense because of roads, jeeps and time constraints. But that is precisely where the pitfall lies. A logistically shorter schedule can be medically much more aggressive. For example, those who skip large stretches and start late at altitude can suddenly find themselves with too few nights in the intermediate zone. Then a route that looks feasible on paper becomes much less forgiving in practice.

For a trek to over 5,400 metres, this is an important distinction. It is not the total trip duration that determines whether you acclimatise well, but mainly how many meaningful nights your body gets between about 3,000 and 4,500 metres. This is why overly tight schedules are often not “efficient” but simply marginless.

Practical tips for fitting day

1. Start early. Not to race, but to move steadily and be over the pass well before noon.
2. Eat early and easily digestible. Appetite is often less at altitude, but an empty tank never helps.
3. Walk at a talking pace. The fitting day is a rhythm assignment, not a fitness test.
4. Keep you warm without sweating. Overheating in the climb and cooling at the crest cost unnecessary energy.
5. Descend to lower sleep. The gain of the day is not only in the pass, but also in the descent to a lower sleeping place.

Conclusion

The Annapurna Circuit altitude profile is treacherous not because it is extremely illogical, but rather because it feels manageable for a long time and then becomes very serious in a short time. Until Manang, you build up relatively gradually. Then comes the real test: how do you react to sleeping above 3,500 metres, how well do you recover in Manang and how much margin do you take towards Yak Kharka and Thorong Phedi?

Those who take that process seriously make the Annapurna Circuit not a lottery but a plan. And that is exactly how best to approach this trek: not as a race against the clock, but as a cleverly constructed acclimatisation story with Thorong La as its logical endpoint.