How travellers can prepare for a high-altitude adventure | Canada Voices

One of my best friends had a habit of dropping random surprises. After his death at 53 in January, 2024, his will included a final act of friendship.

I knew Marcus Stevenson for more than 30 years. He shared my love of travel, canoe trips, hiking, good food and live music. We had a tight group of adventurous companions. Marcus left us $20,000 to take a trip of our choosing, to honour his passion for travel and the outdoors.

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We settled on a hike in the Cordillera Huayhuash, a remote mountain range in Peru with peaks towering upward of 6,000 metres and campsites above 4,000 metres. We’d need support and hired Andean Raju Expeditions to take us on a seven-day trek.

But this is not a story about the trek. It’s a tale about a trek interrupted. At least for me.

We arrived in Huarez, at an elevation of 3,000 metres, in early June. With two nights at a hotel, we took day hikes to reach more than 3,600 metres. (Later I discovered that three days of acclimatization would have been better.)

The day we set off for the Cordillera base, we climbed for seven hours up steep slopes and down hard-scrabble trails, levelling off through a scenic pass before ending at a mossy campsite at the foot of a glacier.

A celebratory beer was in order, followed by a hearty dinner of fish and vegetables. I wrote in my journal and called it a night around 9 p.m. Then I stared at the ceiling for the next nine hours, unable to get a resting heartbeat and tracking a pulse-oximeter oxygen reading I considered low.

I assumed I had altitude sickness, the one variable of a high-altitude trek I couldn’t prepare for or control. We were in a remote region. Every day took us deeper into the mountains and made it more difficult to exit. I consulted with our guide and decided to walk back down and catch a ride to Huarez. I was done.

I have no regrets about my choice, but I did want to learn more. I reached out to Dr. Peter Hackett, specialist in high-altitude medicine and a professor at the University of Colorado School of Medicine.

Would you have done anything differently?

It’s hard to say. The safest thing – if you’re in doubt about having any effect from the altitude and you’re uncomfortable – is to go down. Were you on a group trek?

We had a couple of guides and a cook. There were six of us.

So that’s one of the problems with going with a group – you’re on a fixed itinerary and things like this happen. The guides generally do not want to split up the group and they don’t want to have the whole group stay one day behind, for example. If you’re on your own, it’s a little different than if you’re with a group and your decision-making might be a little different.

What symptoms mean it’s time to pull the plug?

For classic altitude illness, we describe two red flags. One is you start to get pulmonary edema, that’s the fluid collection in the lung. Those symptoms are big-time shortness of breath when going uphill, mild shortness of breath when going straight and not really shortness of breath at rest, yet, and then a cough – usually that develops during the night.

If you don’t catch that early, then the next day that person will be really short of breath and will be struggling if they have a high heart rate, high respiratory rate and a very low oxygen saturation. If the lungs are filling with fluid and you’re having trouble breathing, you need to get out of there.

The second is if the brain is going off and that means a person starts acting drunk, a little confused, maybe slurring, not slurring their speech but not being able to walk a straight line very well, and balance goes off. That’s the second red flag. Those are life-threatening conditions.

Would age and lifestyle factor in, or is genetics the most important factor?

You can’t think that being fit is going to prevent altitude illness or improve your acclimatization. Smokers tend to not have much of a problem unless they have lung disease from their smoking. Alcohol should be minimized at high altitude because it does depress the breathing a little bit. One beer is fine, but you do not want more than that, and caffeine is very good at high altitude. If you use caffeine regularly, you do not want to stop it because you’ll get altitude sickness. You’ll get a bad headache.

The bottom line is anybody can get altitude illness.

In 1982, you established a medical camp on Denali in Alaska. What have you learned about altitude?

We still haven’t improved very much on going down as the main treatment, and oxygen if you have it. We’ve done a lot of work with Diamox, showing it’s beneficial for prevention and somewhat for treatment. It’s not a terribly well-studied area, even though there’s a lot of people at risk. And I think that’s because most of the time altitude sickness is pretty harmless. It’s like a hangover. It goes away by itself.

But we’ve learned a lot about molecular mechanisms and cellular mechanisms that will lead, I’m sure, to better prevention and treatment strategies, and we’ve also learned about things like preacclimatization, which has become a big thing now. People sleeping in oxygen-deprivation tents when they’re at home before they go on their climb.

Based on your research, what percentage of hikers at altitude tend to get some measure of altitude sickness?

For skiers in Colorado it’s 25 per cent. In Nepal it’s 20 to 30 per cent, and for people flying into to Cusco, it’s about 30 per cent. You fly into La Paz, and stay at El Alto, there it’d be 80 per cent because it’s at 14,000 feet.

Hikers need to educate themselves about high-altitude acclimatization and illness and visit a travel practitioner or somebody who knows a little bit about it and can prescribe Diamox. They need to carry Diamox and dexamethasone. Those two medicines are the only two they need to carry, and go slow. Everybody’s body is different.

This interview has been edited and condensed.