What it is
The higher you go, the lower the air pressure and the partial pressure of oxygen. If your body cannot adapt quickly enough you get acute mountain sickness (AMS). Risk starts above roughly 2,500 m and becomes common above 3,000 m.
Symptoms
- Headache — the most common, usually frontal or at the back of the head
- Dizziness, fatigue, loss of appetite, nausea
- Insomnia and periodic breathing at night
- Raised heart rate, cold hands and feet
- Severe: breathlessness at rest, confusion, unsteady walking — descend and seek medical help immediately
How we pace it
- No activity at all on arrival day at altitude.
- Gradual ascent: three full days in Lhasa (3,650 m) before Namtso (4,718 m).
- Oxygen in the vehicle; hotels chosen with lifts and good heating.
- Daily plans adjusted to how you actually feel that morning.
- Guides know the location of local hospitals and oxygen chambers.
Before you go
- Consult a doctor if you have cardiovascular disease, serious respiratory disease, anaemia or sleep apnoea.
- Preventive medication such as acetazolamide is prescription-only and usually started the day before ascent.
- For the first days avoid strenuous activity, alcohol and very hot baths.
- Drink plenty of water, eat small frequent meals, and stay warm — getting cold makes symptoms markedly worse.
Altitudes at a glance
- Xining 2,200 m — most people notice nothing
- Qinghai Lake 3,196 m and Chaka 3,100 m
- Jiuzhaigou 2,000–3,100 m and Huanglong 3,500 m
- Lhasa 3,650 m, Shigatse 3,836 m, Namtso 4,718 m
- Everest Base Camp 5,200 m — border pass required
When to turn back
With persistent vomiting, clear breathlessness, unsteady walking or altered consciousness there is only one correct action: descend and get medical help. Continuing upward makes it worse quickly. We will change the itinerary immediately — safety always overrides the plan.