How long altitude sickness can last

There is no single recovery time. Symptoms may settle over a day or several days as the body acclimatises, but persistent or worsening illness is not something to wait out. Improvement should be judged by how the person feels and functions, not by a deadline on the itinerary.

The height reached, speed of ascent, sleeping elevation, exertion and individual susceptibility all influence the course. Previous fitness does not reliably protect against altitude sickness. A person who keeps climbing after symptoms start may become worse instead of acclimatising.

Mild acute mountain sickness commonly includes headache with nausea, dizziness, fatigue or disturbed sleep after a recent ascent. Recovery is more reassuring when appetite, sleep and energy return and the headache steadily eases. Symptoms from dehydration, infection, migraine or exhaustion can overlap, so an unexpected course deserves medical assessment.

Remain at the current elevation and avoid strenuous activity while symptoms are mild. Drink according to thirst, eat if able, avoid alcohol and sedatives, and tell a companion how you feel. Do not resume ascent until the symptoms have fully resolved.

If there is no clear improvement with rest, move to a lower elevation. Descent is the central response when symptoms are getting worse. Medicines may ease symptoms or support acclimatisation when appropriately prescribed, but temporary relief does not by itself show that it is safe to climb higher.

Confusion, marked drowsiness, loss of coordination, difficulty walking, breathlessness at rest, chest tightness, blue or grey lips, or a worsening cough require immediate descent and urgent medical help. Severe altitude illness can progress even when an earlier headache seemed manageable.

Seek prompt assessment for repeated vomiting, fainting, a severe headache that is not easing, or symptoms that continue after descent. Keep the affected person accompanied, reduce exertion, and use supplemental oxygen when available through trained responders.

Describe the highest sleeping point, daily elevation gains, symptom sequence and what happened after rest or descent. Ask whether the route should be slowed, whether preventive medicine is suitable, and how an existing heart, lung or neurological condition changes the emergency plan.