High altitude shortness of breath: when to act

Mild breathlessness with exertion can occur while acclimatising at altitude, but breathlessness at rest requires stopping ascent and urgent medical assessment. Rest, descend if symptoms persist or worsen, and do not rely on an inhaler or home oxygen unless it has been prescribed and you know how to use it.

At altitude, each breath contains fewer available oxygen molecules because air pressure is lower. Your breathing and heart rate may increase during activity while your body adjusts. Breathlessness can also reflect asthma, anaemia, bronchitis, COPD, a heart rhythm problem, angina, or an allergic emergency. A new cough, wheeze, chest pain, blue lips, swelling, or rapidly worsening symptoms should not be dismissed as normal acclimatisation.

Stop exercising and sit upright in a safe place. Loosen tight clothing, keep warm, and breathe slowly without forcing deep breaths. Do not ascend while symptoms continue. If you have a prescribed reliever inhaler, follow your personal asthma plan. Arrange medical advice if ordinary activity causes unusual breathlessness, particularly if you have heart or lung disease. Descent is the key measure when altitude illness is suspected.

Call emergency services for breathlessness at rest, inability to speak comfortably, chest pain or pressure, fainting, confusion, blue or grey lips, coughing frothy sputum, facial or throat swelling, or sudden wheezing. Do not travel higher. If safe, begin descent with another person while urgent help is arranged; never leave someone severely breathless alone.

Ask whether your heart and lungs are ready for the planned altitude, how to use your prescribed inhaler, and whether you need a gradual itinerary. Explain your usual exercise tolerance, previous altitude symptoms, smoking history, and all medicines.