Does altitude sickness cause nausea?

After a rapid ascent, the body may need time to adjust to thinner air. Nausea can appear with headache, dizziness, tiredness, reduced appetite or poor sleep. Continuing to climb while unwell can make symptoms harder to assess and may allow a serious altitude illness to progress.

Nausea during travel is not specific to altitude. Food illness, motion sickness, infection, dehydration, heat and medicines can produce a similar feeling. Recent ascent and the combination of symptoms give useful context, but a clinician may be needed for a safe assessment.

Stop ascending and rest at the same altitude. Take small, frequent sips of fluid if you can keep them down, choose light food when able, and avoid alcohol and strenuous activity. Tell someone in your group that you feel unwell.

If symptoms persist, worsen or prevent you from drinking, seek medical advice and descend to a lower altitude when advised. Do not take unfamiliar medicines without checking that they are suitable for you.

Seek urgent help for repeated vomiting, confusion, unusual drowsiness, trouble walking, breathlessness at rest, or a severe or worsening headache. These signs can point to a serious altitude problem requiring rapid descent and medical care.

Ask how to acclimatise safely, what to do if you cannot keep fluids down, which medicines may be appropriate for your trip, and which symptoms require immediate descent.