What should you know about altitude and headaches?

Pause further ascent, rest and pay attention to whether symptoms settle or progress. A headache that worsens despite rest, or occurs with poor coordination, confusion or breathlessness at rest, calls for descent and urgent medical help.

Air pressure falls with elevation, reducing the oxygen available with each breath. The body needs time to adjust its breathing and circulation. Ascending quickly, exerting yourself soon after arrival, poor sleep and dehydration can make a headache more noticeable.

Timing matters. An altitude-related headache begins after a gain in elevation and may occur alongside loss of appetite, nausea, lightheadedness or unusual fatigue. Nasal congestion, heat illness, migraine and infection can also cause head pain, so the surrounding symptoms and response to descent help guide assessment.

Stop climbing and take it easy at your current elevation. Drink according to thirst, eat if you can and avoid alcohol or intense exercise while unwell. A familiar over-the-counter pain reliever may help if it is normally safe for you, but relief should not be used as permission to climb higher.

If symptoms do not improve, move to a lower elevation with a companion. For future trips, allow more time for acclimatisation and build rest into the ascent. People with long-term medical conditions or previous severe altitude symptoms should discuss travel plans with a clinician beforehand.

Descend and obtain urgent medical help if a headache is severe or worsening, or if there is confusion, unusual drowsiness, loss of coordination, difficulty walking, weakness, fainting, repeated vomiting, chest tightness or shortness of breath while resting. Do not leave an affected person alone.

A sudden explosive headache, new speech or vision trouble, a seizure, stiff neck or one-sided weakness also needs emergency assessment, whether or not altitude seems relevant.

Discuss whether your route allows gradual adjustment, which medicines are suitable for you, and how an existing heart, lung or neurological condition changes the plan. Tell the clinician how high you travelled, how rapidly you ascended, when pain began, what other symptoms occurred and whether descent helped.