How to

16 May 2016

Dealing with High Altitude

Whether you’re hiking, skiing or mountaineering, the cold isn’t the only thing you have to be concerned about. The higher you get, the thinner the air becomes, meaning you can’t draw as much oxygen from it. Low oxygen saturation (levels of oxygen in the blood) can lead to dizziness, exhaustion, nausea, headaches and other complications. Beyond that you can experience pulmonary oedemas – fluid collecting in cavities in the lungs, making it harder to breathe. If this condition occurs and is allowed to carry on unaddressed, it can be life threatening.

For these reasons, if you’re planning on going somewhere with altitudes of 2,500 meters or higher, you need to know how to deal with altitude sickness. Knowing what to expect, and what approach to take, could mean the difference between a fulfilling expedition and a medical emergency, and it could even save your life.

It’s Not Just About Height

You could be forgiven for thinking that the biggest factor in altitude sickness is, well, altitude, but this isn’t necessarily the case. As the air gets thinner, your body has to work harder to keep itself running at even normal rates, so overexerting yourself is going to place you in much greater risk. It’s often said that younger, fitter people are at greater risk of altitude sickness, simply because they’re more likely to try and race up to the summit, just because they can.

Rushing doesn’t allow your body enough time to acclimatise, and as you ascend, the rate of atmospheric extremity intensifies. Simply put, your best bet is to move slowly to give your body time to adjust to the changing air density. The higher you climb, the longer your body needs to adjust, which is why climbers will spend days at a time at base camps beyond a certain height.

Hydration and Nutrition

Breathing isn’t the only way your body absorbs energy, food and drink are just as important, and far more so at height. Since you’re absorbing far less energy through respiration, you need to take in that much more in other ways. Altitude sickness, at any level, will make you less interested in food, so it’s better to bring a litany of high carb snacks, palatable and easy to eat quickly. Sweets like lemon drops, hard candies and jelly beans are good, but beyond that you want to look at energy bars, granola, dried nuts and rice-based meals, especially freeze dried ones.

As far as staying hydrated is concerned, you need to be drinking water constantly, regardless of how thirsty you may or may not feel. In fact, if you feel thirsty, you have a problem, because that means dehydration has already started to set in, and if that’s the case you need to stop and rest until the thirst subsides. A camel back is always a wise idea, as it means that you never have to go to any significant effort to get your water. If you’re climbing really high, be sure it’s insulated. Other liquids can act as an additional source of carbs; isotonic drinks like Gatorade are good, as is (non-alcoholic) cider, and hot drinks like cocoa and tea.


If you’ve never been on a high altitude expedition before, it’s important not to rush into it without getting some idea of what you’re in for. Doing interval training sessions with all the gear you’ll be taking at normal altitude is important, as is spending some time simply existing at height, just to get a sense of what it will be like when you actually go on a climb.

If you’re already at least somewhat used to the feeling of being at high altitude before you actually go on a proper expedition, it’s one less thing to be concerned about, and if you’re used to carrying all the gear, and know how to move properly through the snow drifts and whatever else, so much the better.


If you’re going to take any kind of medication at height, you have to consult a doctor first. Many climbers find that aspirin can be helpful when you start to reach certain heights, as headaches are a common symptom of even the most mild altitude adjustment. Any kind of depressant should be absolutely avoided – any kind of opiate, tranquiliser, anything with alcohol, barbiturate, or sleeping pills. The last is particularly important because it’s very difficult to sleep when the air is thin, but it’s something you just have to learn to cope with.

Medications specifically designed to help with issues brought about by high altitude do exist, but once again you need to speak to your doctor about those, as many have side effects.

Know When to Quit

Low levels of altitude sickness (AMS) should not deter you from carrying on. As long you take enough time to acclimatise before carrying on to each subsequent leg some symptoms are fairly normal, and should be accordingly addressed by either slowing down, stopping to rest, eating, drinking or taking medication, as described above. If symptoms intensify you need to start thinking about heading back down, or even getting emergency medical attention.

Always speak openly about your symptoms, and hike in the company of more experienced climbers who can recognise the distinction between mild and pronounced AMS. Typically, if the headaches become more severe, the nausea causes vomiting or, most significantly, co-ordination drops (ataxia), the AMS is no longer mild enough for you to continue. The ataxia is easy to test for, simply attempt (or ask the potential sufferer to attempt) to walk heel to toe, like a drink-driving test. If they can’t do it they need to start descending immediately, but at a steady pace, before they lose the ability to walk altogether.

At that stage, time spent at a slightly lower altitude can allow the symptoms to subside enough for them can carry on. If the AMS reaches the point of severity, this is no longer an option. There are two conditions associated with severe AMS, both of which are considered medical emergencies – pulmonary oedema and altitude cerebral oedema. 
The first is a build-up of fluid in the lungs, and can be identified through the following symptoms:

  • Shortness of breath, even at rest
  • A tight, constricted feeling in the chest
  • Coughing up white or frothy fluid
  • A feeling of weakness and tiredness
  • A feeling of suffocation at night
  • Confusion and irrational behaviour

The second is a swelling of brain tissue, and can be identified through these symptoms:

  • Persistent headaches
  • Confusion and disorientation
  • Decreased consciousness
  • Memory loss
  • Hallucinations
  • Psychosis
  • Lack of co-ordination
  • Coma

If you exhibit, or see anyone else exhibiting any of these, it is a potentially life threatening emergency, descent and evacuation to a medical facility is mandatory in either case. There will be someone on the expedition with you who is properly trained to deal with such an issue, and it is vitally important that they are made aware immediately.

Callum Davies

Callum is a film school graduate who is now making a name for himself as a journalist and content writer. His vices include flat whites and 90s hip-hop.