Tips for Preventing Altitude Sickness

TRAINING | by DI WESTAWAY | 12 May '18

Tips for Preventing Altitude Sickness on your World Class Trek

  • Gain altitude slowly. As a rough guide, above 2,500m the maximum height gain between sleeping altitudes should not exceed 300m per day, with a rest day for every 1000m of ascent or every third day. 
  • Only ascend when there are no symptoms of Acute Mountain Sickness. (Acute Mountain Sickness, or AMS is not life threatening and is very
  • common).
  • Avoid over -exertion and avoid getting out of breath while acclimatising, especially if experiencing symptoms of AMS.
  • Drink enough liquid to keep your urine pale and plentiful. 
  • Avoid alcohol, caffeine, excess salt. 
  • Use the buddy system to keep an eye on each other for symptoms of AMS.
  • Use technical walking during the ascent, focusing on “The Brigitte” technique of locking the back knee and pausing momentarily with each step. (See Chapter 1)
  • Use Diamox, which is universally considered the most tried and tested drug for altitude sickness. You must consult your doctor before using this drug. (See below for more information on Diamox).
  • Ensure your itinerary allows you to climb high, and sleep low as you’re acclimatising.
  • Avoid medications that depress respiration (eg sleeping tablets, sedatives, strong pain killers and antihistamines) as these increase the risk of AMS. If you must take any of these, consider using Diamox as well, and consult your doctor before you go.
  • If you must fly or drive rapidly to 2,500m or higher, spend a minimum of two nights at your arrival altitude, or till symptoms disappear, before ascending.
  • If ascending rapidly to 3,000m or higher, consider using Diamox. (125 to 250mg 12 hourly, start at least one day before your initial ascent and continue for three days after arrival).
  • Make your bed on an upwardly sloping angle and use a blow up pillow, or pillow case stuffed with soft clothes to elevate your head and reduce those ugly eyes that come from sleeping at altitude.


DIAMOX: To use or not to use.

Diamox is the most tried and tested drug for altitude sickness prevention and treatment. It is so universally accepted on high altitude treks that often your guide will tell you to use it and sometimes they will even supply you with the drug. It is essential to consult your travel doctor before you depart, and also to practice using Diamox at home to ensure you don’t have any unusual reactions to it.

When trekking to Everest Base Camp, Tibet, climbing Mt Kilimanjaro and trekking to Machu Picchu, our guide recommended we use Diamox preventatively to assist with acclimatisation. Most of the girls heeded this advice, but some chose to use Diamox therapeutically instead, and others used herbal and natural remedies prescribed by a naturopath. Some of the girls did not use it at all and still managed to summit and climb at altitude.

On our Kangshung Face Trek, we spent three days in Lhasa, 3,400m, then trekked over a stunning 5,500m pass within 5 days, which is quite a rapid ascent. All 18 women managed the altitude but some of the girls found it extremely challenging.

One of our more experienced team members, Sonja, was put in a Gamow Bag at 4,900m, to relieve the symptoms of altitude sickness. 

She suffered very bad headaches and eally struggled to walk. The Gamow bag, which is a compression chamber, is a sealed plastic cylinder  into which air is pumped to increase the pressure, thereby reproducing a lower altitude pressure. Within 90 minutes, Sonja’s symptoms were relieved and she continued on the trek. She climbed over the 5,500m pass and made a full recovery on descent.

The Science

Diamox does not mask the symptoms of altitude sickness, but actually treats the problem. It seems to work by increasing the amount of alkali (bicarbonate) excreted in the urine, making the blood more acidic. Acidifying the blood drives the ventilation, which is the cornerstone of acclimatisation. For prevention, 125 – 250mg twice daily starting one or two days before and continuing for three days once the highest altitude is reached is effective. Studies have shown that prophylactic administration of Diamox at a dose of 250mg every eight to 12 hours before and during rapid ascent to altitude results in fewer and/or less severe symptoms of acute mountain sickness (AMS). Common symptoms include headaches, nausea, shortness of breath, dizziness, drowsiness, and fatigue. Pulmonary, or lung function, is greater in both subjects with mild AMS and asymptomatic subjects. The treated climbers also had less difficulty in sleeping.

Some experienced high altitude climbers only use Diamox to assist with sleep. In this case, they take Diamox an hour before bed and this allows them to have a much better quality sleep. Clearly this results in less fatigue and better health for climbing through the day. 

Gradual ascent is always desirable to try to avoid acute mountain sickness. However, if rapid ascent is undertaken on Diamox and severe forms of high altitude sickness, (such as pulmonary or cerebral edema) occur, prompt descent is essential.

Possible side effects of Diamox include: uncomfortable tingling in the fingers, toes and face; increased urinary volume, nausea, drowsiness, myopia, temporary impotence, carbonated drinks tasting flat, excessive urination, and rarely, blurring vision. Diamox should not be given to pregnant women or anyone with a history of sulfur allergy.


Tips for Diamox users

  • One disadvantage of using Diamox is that it is a diuretic. This means there is increased potential for dehydration, so you must be very vigilant about drinking. 
  • As your body is acclimatising, you will get completely sick of drinking and you’ll be looking for alternatives to tea!
  • We recommend you bring your own herbal teas, de-caffeinated coffee, hot chocolate, hot cordial, Tang, Gastrolyte, Hydrolyte, packet soups and any other options you can think of to get liquid into you.
  • You will pee a lot on Diamox, so ensure that you carry a wee funnel for day time wee and a pee bottle or zip lock bag for night time wee.
  • DO NOT be tempted to reduce your liquid intake because you don’t want to pee at night. This can be very dangerous at altitude, so you need to ensure that you have “In tent” options for weeing.


The Point of No Return

I have had the great privilege of trekking and climbing at altitude around the world many times with many different women and mixed groups. I have climbed to 7,000m to the summit of Mt Aconcagua with a team of Wild Women On Top. But I have twice made the decision to turn around short of my goal: once on Mt Aconcagua at 6,000m and once on Mt Everest at 6,400m. 

On both of these occasions, I was in mixed groups, not involved in developing the itinerary and not in a leadership role. On both occasions I turned back because of fear. On the first occasion the fear came from lack of experience and on the second occasion it came from altitude sickness: Chyanne Stroke Breathing which can lead to Pulmonary Edema. On both occasions I did not have enough time to acclimatise. If your goal is to summit a high mountain or trek a particularly high pass, I strongly recommend that you ensure your high altitude itinerary allows plenty of time for acclimatisation. You will know this by thoroughly researching your trek and seeking out an itinerary which allows you to climb high and sleep low, and does not exceed the recommended 300m per day rate of ascent.

For more information on this topic, please consult Jim Duff’s book, “Pocket First Aid and Wilderness Medicine”.



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