Acclimatisation days on the Everest Base Camp trek

Acclimatisation is the process by which your body adjusts to lower oxygen levels, and it takes time rather than effort. On the Everest trail the two traditional rest stops are Namche Bazaar at about 3,440 m and Dingboche at about 4,410 m. Each gives you an extra night at the same altitude with a short, optional hike that helps the process.

Why these two places

Namche is the first big step up, and many people feel the altitude properly for the first time here. Dingboche, or sometimes Pheriche, sits at the point where the trail passes 4,000 m and the nights start to become uncomfortable for many trekkers. Putting rest days at these points follows the general rule of taking one every 1,000 m or every three to four days of climbing.

Climb high, sleep low

A rest day does not mean doing nothing. The standard approach is to walk higher during the day, then return to sleep at a lower altitude. This gives your body a taste of thinner air without the strain of sleeping there.

• At Namche: a walk toward the Everest View area or Khumjung, climbing a few hundred metres before coming back down.
• At Dingboche: a steady climb on the ridge behind the village to about 4,800 m, or a walk toward Chukhung, then return.

What to do on the rest of the day

Drink plenty of water, eat properly, wash your hands carefully, and rest. Avoid alcohol and do not use the day to climb as high as possible. Keep your pace gentle on the hike so that you finish feeling tired but not exhausted.

Signs you need an extra day

If you have a headache that is not fading, poor appetite, broken sleep and nausea, an extra day at the same altitude can help. If symptoms are worsening rather than improving, the safe answer is to descend. Do not rely on the schedule to make decisions for you.

Flexible plans work best

Itineraries with one or two spare days let you add a rest day where you need it. A tight plan with no slack leaves you with only one choice if you feel unwell, which is to stop and go down.

What changes in your body

During the first days at altitude you breathe more deeply, your heart rate rises and you pass more urine. Over the following days your body produces more oxygen-carrying red cells and adjusts the chemistry of the blood. These changes are gradual, so rest, fluids and patience do more than any gadget or supplement. People who rush often find that the benefits of a short itinerary disappear in a night of headache and sickness.

Choosing a good rest-day walk

A good acclimatisation walk takes you several hundred metres above the village and brings you back down. At Namche, popular options include the climb towards the Everest View Hotel area or the walk to Khumjung. At Dingboche, the ridge behind the village gives views of Ama Dablam and the opposite valleys. Go at a gentle pace, carry water and a warm layer, and turn around if you feel unwell. The point is not to test yourself but to give your body a mild stimulus.

Using the rest of the day well

Once you return, resist the temptation to nap all afternoon, which can interfere with sleep at night. Wash clothes, write a diary, read, play cards, walk gently around the village or visit a local museum or bakery if available. A short stroll and a good meal are better than lying down for hours. Drink plenty of fluids and keep warm in the evening.

Thinking beyond the standard plan

• If you ascended in a hurry before arrival, for example by flying straight to Lukla after a long journey, ask for an additional night low down.
• If you are a poor sleeper, consider adding an extra night at 4,400 m.
• If your guide proposes an additional day, accept it. Experienced guides recommend it for good reasons.