John Muir Trail: Altitude Sickness, Part 2

Last week I talked about practical ways to avoid altitude sickness.

(Here’s another, less than practical solution: take a semester at Adam’s State University in Colorado, culminating a few days before the hike. The campus elevation: 7,500 feet!)

The topic this week: what does altitude sickness feel like, and how serious can it be?

First of all, you should know that the term “altitude sickness” covers a whole continuum of ailments, from minor annoyances, to something that will kill you with alarming swiftness. Even worse, the more serious complications carry the added risk of irrational behavior—you might be happy as a clam as you walk to your doom.

The most common symptoms are headaches, a little nausea and general lethargy. A good portion of the hikers who attempt the John Muir Trail are going to experience these (whether they are caused by altitude sickness, dehydration, not eating enough calories, insufficient pre-hike training, or something else). The potential remedies should sound familiar: stay hydrated, stay well-rested and make sure you’re eating enough. Sleep at the lowest elevation possible.

Truthfully, I get these symptoms every time (even though I follow the rules from last week’s post, religiously). For me, ibuprofen does a good job on the headache, and the beauty of the trail combined with the thrill of being out there is enough to distract me from the upset stomach and sluggishness. I find that these complaints disappear within a few days, although they can come back if I get sloppy in regards to hydration and calorie intake. For example, my worst case of altitude sickness came on the evening of day eight. Why? Because I had done a very poor job that day of eating and drinking.

A moderate form of altitude sickness consists mostly of the same symptoms, only worse. You might also feel lightheaded, experience paresthesia, and even get nosebleeds. Your hands and feet might swell, although they are almost certainly going to do so, anyway, from the hiking. If the remedies I describe, above, don’t do the trick, you are going to have to make a judgment call on whether or not you should continue. More about judgment calls at the end of this article.

The most serious of the types of altitude sickness are the edemas: pulmonary and cerebral. High altitude pulmonary edema (HAPE) occurs when fluid accumulates in the lungs, substantially affecting their ability to oxygenate the blood. This is an extraordinarily dangerous situation. Until this year, when I lost someone very close to me due to lung problems, I had no idea just how thin the margins are when it comes to oxygen in the blood. Most of us walk around with nearly 100% oxygenation. When that level drops below 95%, it’s a problem. Below 90% can be catastrophic. That’s what HAPE can do to you.

I experienced a mild bout of HAPE during my last thru-hike. There was a fire in Yosemite Valley on the day I hiked out, and I sucked in a lot of smoke (and, therefore, particulate matter). As the first few days passed, it got increasingly uncomfortable for me to breathe. It was especially a problem at night, when I would wheeze so loudly that it kept me awake.

When I got to Red’s Meadow, I took a rest day and went to see a doctor in the town of Mammoth. (There’s a shuttle that takes you into town.) He did a quick exam, confirmed that I had a mild case of HAPE, prescribed some medication, and told me I could start hiking the next day. I took the pills, rested the remainder of that day, and walked out of Red’s Meadow feeling great. HAPE doesn’t have to end your hike, but neither should it be ignored.

HACE means a trip to the hospital as quickly as possible!

The second of the edemas is high altitude cerebral edema (HACE). Just as HAPE is fluid in the lungs, HACE is fluid (and swelling) in the brain. This is by far the most dangerous of the potential ailments categorized as altitude sickness. A hiker with HACE might exhibit all of the symptoms I’ve already described, above, along with another that makes it even more deadly: disorientation and irrational decision making. In some cases the hiker may even hallucinate.

If you come across a hiker at high elevation who looks drunk, but isn’t, there is only one course of action: descend as quickly and as safely possible. Once you’re off the trail they need to be put under a doctor’s care.

My last recommendation is that you do more than just read a blog to prepare, medically, for your hike. Spend some time with a doctor familiar with hiking at high altitude. This is not only a good way to learn about altitude sickness, but it will also give the doctor a chance to explain how hiking at high elevation might affect YOU, specifically. (Perhaps you are on some medication that is relevant.) Learning as much as possible from a physician who knows about backcountry hiking will expand your foundation of knowledge, so that when you have to make a judgment call, it’s more likely to be a good one.

Good hiking, Ray