Altitude Sickness

Altitude sickness, also called “mountain sickness,” are symptoms that arise when you ascend to high elevations too quickly without suitable acclimatisation. As the elevation increases, atmospheric pressure drops. This leads to less oxygen being available with each breath.

What is Altitude Sickness

Those who live at lower altitudes will notice the air feels thinner as you get higher, many people feel they get out of breath more quickly, even at moderate altitudes of 1,500m. This becomes more pronounced the higher you go, and is why climbing the tallest peaks requires oxygen for most people.

Rapid transitions to higher elevations can overwhelm the body’s ability to adapt through acclimatisation. This is the body gradually adjusting to reduced oxygen levels which takes three to five days.

Altitude sickness usually occurs at heights of above 2,400m. The higher the elevation and faster the ascent the more likely it is to occur. It can be a serious challenge even for the fittest individuals, including athletes.

Travelling to destinations at high altitude is exciting and very rewarding. But it’s also challenging with there are additional risks. So you should have a travel insurance policy that covers high altitude, including medical evacuation and repatriation.

Symptoms and Types of Altitude Sickness

There are three types of altitude sickness with:

Acute Mountain Sickness (AMS): The mildest and most common form of altitude sickness. AMS is often compared to a hangover, presenting symptoms like headaches, dizziness, muscle aches, nausea, fatigue, shortness of breath, loss of appetite and sleep disturbance.
High-Altitude Pulmonary Edema (HAPE): This is a serious condition as it involves fluid accumulation in the lungs which can be life-threatening. Symptoms include those above, but also severe breathlessness, a cough producing frothy sputum and chest tightness.
High-Altitude Cerebral Edema (HACE): The most severe form of altitude sickness. With HACE you get fluid on the brain, leading to confusion, severe headaches, an inability to walk and even falling into a coma. Immediate medical intervention is crucial.

Symptoms of altitude sickness typically emerge within 12 to 24 hours of reaching a higher altitude. It is common for mild symptoms to pass over time. But they can also get much worse very quickly.

Prevention of Altitude Sickness

The key to preventing altitude sickness is acclimatisation. The following is recommended:

Gradual Ascent: Avoid rapid ascents to altitudes above 2,400m. Begin below 3,000m and ascend slowly, ideally not exceeding 300m overall gain per day. For every 900-1,000m that you climb, take a rest day.
Climb High, Sleep Low: You can ascend to higher altitudes during the day but return to lower altitudes to sleep.
Hydration and Diet: Drink 3-4 litres of water daily and maintain a diet high in carbohydrates. Avoid alcohol, tobacco and sedatives, especially in the first 48 hours at altitude.
Medications: Acetazolamide (Diamox) can speed up acclimatisation by promoting breathing and oxygen absorption. However, it does not replace the need for gradual ascent.
Awareness: Be vigilant for early symptoms of altitude sickness in yourself and others. Be prepared to descend immediately if symptoms develop.

Treatment of Altitude Sickness

You can usually overcome mild altitude sickness by resting at the current altitude. Stay warm and keep yourself hydrated. Over-the-counter medications like ibuprofen can alleviate headaches.

If symptoms persist or get worse, descent to a lower altitude is essential. Rest and acclimatise until you are fit enough to resume the trek. If AMS does not improve, abort the trek, as nothing is more precious than your life.

Carrying oxygen and/or Portable Altitude Chambers (a.k.a. Gamow Bag/Hyperbaric Bag) can be a life saver. A Gamow Bag simulates the atmosphere at 1000m lower, and is particularly useful in the middle of nowhere, or where it is difficult to descend.

Severe AMS, HAPE and HACE are life threatening. So, if altitude sickness worsens, communicate with emergency services, directly or via your host/guide, to arrange immediate rescue.

In severe altitude sickness cases, such as HAPE or HACE, immediate descent and medical treatment are critical. Supplemental oxygen, steroids like dexamethasone for HACE, and medications such as nifedipine for HAPE, are often necessary.

Considerations for Pre-existing Conditions and Pregnancy

Anyone, regardless of fitness or health, can develop altitude sickness. But fast ascents, high altitudes reached and the height at which you sleep are all contributing factors.

Living at altitude provides acclimatisation, but sudden ascents to significantly higher elevations still pose a risk. Age, previous experiences with altitude sickness, and preexisting conditions like sickle cell anaemia, COPD, heart conditions, recent heart attacks or strokes also play a role. So, consult healthcare professionals before travelling to high altitudes.

Pregnant women should also seek advice from their obstetrician or midwife to ensure safe travel plans. It is also recommended that babies under three months old are not taken to moderately high elevations, for example on a ski holiday, if they usually live at a low altitude.

Conclusion

Altitude sickness should always be taken seriously. It is a potentially life-threatening condition that requires awareness, preventive measures and prompt treatment. Understanding the symptoms, recognising risk factors and suitable acclimatisation significantly reduce the chance of it ruining your trip.

Whether you’re a super fit athlete, seasoned climber, unfit skier or a casual traveller, altitude sickness can affect you. If you start to feel ill, tell someone immediately, even if it is just a headache or mild nausea. If conditions get worse they can help, but they won’t know if you don’t tell them!