Welcome to the Mike Varney Physiotherapy News and Advice blog

Acute Mountain Sickness

In light of recent events, with our staff and patients taking on challenges that push you through both mental and physical exhaustion above 2,500m, we thought we would take a look at one of the main conditions they may be up against…

Acute mountain sickness (AMS) is an illness that can affect mountain climbers, hikers, or skiers at high altitudes, usually above 2,400 meters. It is caused by reduced air pressure and lower oxygen levels at high altitudes and can come on more dramatically the faster you climb. There is not enough evidence to suggest why AMS is connected to shortage of oxygen but some scientists believe that it is due to swelling of the brain. It is also difficult to determine who may be affected by AMS since there are no specific factors such as age, sex or physical fitness that correlate with it. There are many stories of fit and healthy people being badly effected by AMS, while their older companions have felt no effects at all.


Symptoms will also depend on the speed of your climb and how hard you push yourself. Symptoms can range from mild to life-threatening and can affect the nervous system, lungs, muscles and heart. Mild symptoms can include:

  • Difficulty sleeping
  • Dizziness or light-headedness
  • Fatigue
  • Headache
  • Loss of appetite
  • Nausea or vomiting
  • Rapid Pulse (heart rate)
  • Shortness of breath during activity

More severe acute mountain sickness can include:

  • Blue colour to the skin (cyanosis) or grey complexion
  • Chest tightness or congestion
  • Confusion
  • Coughing up blood
  • Unconsciousness or withdrawal from social interaction
  • Cannot walk in a straight line, or walk at all
  • Shortness of breath at rest

Early diagnosis is important as acute mountain sickness is easier to treat in the early stages. The easiest and main treatment recommended is to climb down to a lower altitude as rapidly and safely as possible. Extra oxygen should be given, if available but the more severe may need to be admitted to a hospital.


A gradual climb up into altitude with stops for a day or two every 600m above 2,400m will aid in preventing AMS. The body has an amazing ability to acclimatise to altitude, but it needs time. For instance, it takes about a week to adapt to an altitude of 5000m, however most tours or treks to summits are time constricted and do not allow enough time to acclimatise correctly. It is also advisable to sleep at a lower altitude when possible to aid in acclimatisation. However one of the most important preventive techniques is learning how to recognise early symptoms of mountain sickness.

If you plan on quickly climbing to a high altitude, ask your doctor about a medication called acetazolamide (Diamox). This drug helps your body get used to higher altitudes more quickly, and reduces minor symptoms. It should be taken the day before you climb, and then for the next 1 to 2 days.



Figure.1. Wilson, Newman, Imray (2009) The cerebral effects of ascent to high altitudes.



We would like to wish all our patients and staff members taking on their challenges the best of luck and good health. If you are planning a large event or charity challenge and would like advice or treatment, please contact us on 01279 414959 to book an appointment.

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