How common is headache in altitude sickness?

At higher elevations, the body has less available oxygen than it is used to. During adjustment, a headache may develop with nausea, poor sleep, dizziness, fatigue or reduced appetite. The timing matters: symptoms that begin after ascent are different from a familiar headache that happens to occur while travelling.

A headache does not by itself establish altitude sickness. Dehydration, missed meals, alcohol, migraine and other illnesses can also cause pain. New or unusual symptoms deserve attention, especially when they worsen as you remain at altitude.

Stop further ascent while you assess how you feel. Rest, drink fluids and avoid alcohol or strenuous exertion. Tell a travel companion or local guide about the symptoms, and follow any acclimatisation plan given for your trip. If the headache is not improving, seek local medical advice before continuing higher.

For future trips, allow time for gradual acclimatisation. Discuss prior altitude illness and any planned preventive medicine with a clinician before travel, particularly if you have heart or lung disease.

Descend and get urgent medical help if headache becomes severe or is accompanied by confusion, unusual behaviour, poor coordination, trouble walking straight, severe breathlessness at rest, a persistent cough, blue or grey lips, or fainting. Do not continue climbing with these symptoms. If emergency services are available, contact them.

Could my planned elevation and rate of ascent increase my risk of altitude illness? What symptoms mean I should stop ascending or descend? Are any medicines or health conditions relevant to my travel plan?