Now I like to get high as much as the next man, but that doesn’t mean I want to stay high for days on end, in body or mind. That way lies madness, and possibly death. You see, my puny corporeal vessel isn’t used to the depleted oxygen levels over 3,000 meters. This boy was born in humble Birmingham, UK, a meager 140 meters above sea level.

What happens to the human body in oxygen-poor atmospheres is fascinating enough to fill entire biology books, but to summarize: In thin air, less oxygen is absorbed into our blood with each breath (hypoxemia), thus our brains are not receiving the amount of O2 to which they’ve become accustomed (hypoxia) and cease to function properly.

The trademark symptoms of hypoxemic hypoxia are light-headedness, headaches, tiredness, arrhythmia, nausea, euphoria, disassociation from self, memory loss, disorientation, and eventually loss of consciousness. Most of the time these symptoms abate soon after descent to a lower, more oxygen-rich environment.


But not for me. Not anymore.

I’m not a highly accomplished mountaineer by any means, but I used to rock altitude. I’d experience shortness of breath, of course, but apart from a touch of light headedness, my mental faculties were unaffected. Yes, I could handle 6,000 meters with no problems. Until I couldn’t.

It was Aconcagua, where I first noticed a change. I was working as a trekking guide. My small group had dropped out one by one due to AMS, fitness issues or, most frustratingly, some sort of glacier lassitude reminiscent of Tom Burley’s in The Ascent of Rum Doodle. We were at the bottom of the Canaleta, about 6,650 meters, when one of my clients announced she’d done enough, and didn’t feel the need to go any further. It was early on a beautiful summit day, and she was physically strong, but we just couldn’t persuade her to finish the job, so we started back down.

I was affected by the altitude at this point, and I knew it. The thing is … I didn’t care. I was euphoric. I strode back along the exposed traverse known as the Travesia, a 30° snow slope with a run-out that would have Reinhold Messner groping for his ice screws. To slip here would have been problematic, potentially fatal, but although I saw the danger, I didn’t take any special precautions against it. I just skipped blithely along, content that if I tripped, slipped and died, it wouldn’t really matter. It was the epitome of disassociation from self.

The author, contemplating the dragon, Aconcagua. 

Such wild abandon is in itself not unusual, but after sleeping at Camp 4 that night, descending to base camp, then trekking back towards Puente del Inca, I still hadn’t come to my senses. I’d remember things I’d done seconds ago with a wistful nostalgia more suited to recollections of my childhood. It was trippy.

However, the elation of this dream-state was beginning to wear off, replaced by mild worry at my continued negligence. No one else in my team was still dancing with the magic dragon, so why was I? None of the other classic symptoms persisted, but I’d wake up every morning and concentrate for a few seconds before thinking, yep, still high as a kite.’ It must’ve lasted a week.

I’m aware that every trip to altitude is unique and can result in markedly different reactions from the same body. Even seasoned mountaineers with years of problem-free climbs can suddenly be severely affected, but my increased susceptibility to mental detachment has never receded. I don’t scale those dizzy heights anymore, but on a recent trip to Mount Stanley in Uganda’s Rwenzori range (5,109 meters) that familiar feeling of enraptured recklessness assailed me and, true to form, dogged me relentlessly throughout the descent.

Knee-deep in a river of mud one day, I realized this prolonged feeling of giddiness is exactly what people are seeking when they engage in so-called ‘breath play’, or auto-erotic asphyxiation. I’d inadvertently achieved a state that around 1,000 people per year die chasing.

Once safely home, I asked some mountaineering friends for their experiences. Casual diagnoses, admittedly unprofessional, ranged from mild HAPE, to ‘oxygen paradox’ (whatever that is) to basic dehydration. Andrew Lock (first Australian to climb all the 8,000ers) told me he’d never experienced prolonged hypoxia himself, and had always noticed his body responding immediately to the increased oxygen on descent. Tim Macartney-Snape (first Australian to climb Everest) also smashed his recoveries, although he did offer a morsel of hope: “I’ve seen people with a glazed look in their eyes even a week after coming down,” he said. “Sorry I can’t be of more help,” he continued, “If only I’d not gone to altitude so much.” Thanks, Tim.

Still none the wiser, I contacted Bill Crozier, a Brisbane-based anesthesiologist and expedition doctor, who warned the effect of altitude on the nervous system is undoubtedly profound. “Many studies have shown cognitive impairment for several days to weeks, in even the best climbers. Simple testing, such as hand-nose co-ordination and sorting shapes and colours, is some measure of impairment and recovery. Brain scans have also been used of late, and show focal problems that can arise on any expedition. Small retinal haemorrhages are common, although we’re mostly unaware of them.”

At least now I was in the company of “even the best climbers.” Crozier also pointed me at some seminal works on the subject. Thomas Hornbein’s paper, The High Altitude Brain (Hornbein, 2001), contends that neuro-behavioral changes often persist after returning to lower altitudes. One study of a group of mountaineers (Regard et al, 1989), who had climbed above 8,500 meters without supplemental oxygen, showed impaired concentration, short-term memory and cognitive flexibility, plus EEG abnormalities, between two and ten months after descent. Ten months! I might still be suffering even as I write this.

The evidence was mounting that I wasn’t alone in my altitude hangover, or as it was now being worryingly referred to in these scientific papers—brain injury. Despite trudging through several deeply technical studies measuring various bodily changes using large and expensive machines with three-letter acronyms, I could find none that satisfactorily explained the permanence of my disability.

And then a clue: according to Hornbein, a higher Ventilatory Response to Hypoxia (HVR) is associated with decreased cerebral blood flow accompanied by increased arterial oxygen content; i.e. the brain is starving while the muscles are feasting on O2. This combination of impairment in brain function with an operational body was commensurate with my experiences. Maybe my HVR had gone through the roof? Unfortunately, a measurement of that complexity couldn’t be done at home with a paper bag and an iPhone app, and so my ignorance continued.

No place for a blissful miscalc. 

In a last ditch attempt at enlightenment, I went to Brenton Systermans, expedition doctor with the Himalayan Rescue Association and the Australian Antarctic Division. His cautious diagnosis was HAP – High Altitude Psychosis. Temporary insanity? I could live with that. Possible symptoms of psychosis include hallucinations, delusions, disorganized speech, depression, mania, and impaired cognition, although only the latter applied to my condition. The worrying medico-speak didn’t end there either; Ryn’s Psychpathology in Mountaineering (Ryn, 1988) noted that ‘acute organic brain syndrome’ had been found to occur above 7,000 meters, and featured impaired judgement or psychosis which could directly threaten survival. No shit.

In support of his reasoning, Systermans pointed me towards a more recent paper (Hufner et al, 2018), which concluded that “psychosis can occur … in the absence of other signs and symptoms of HACE. Isolated HA psychosis should thus be considered a distinct and separate HA-related syndrome.” This explains why, along with 28% of the cases in the study, I didn’t experience the bubbling lungs, splitting headaches, or indeed, death, associated with pulmonary or cerebral edema. Interestingly, of those 28%, 33% reported depersonalization, i.e. the persistent sense that one’s surroundings aren’t real. Bingo!

Both explanations were plausible, but why the sudden onset? Age was the obvious culprit. According to one paper (Griva et al, 2017), “Age was significantly associated with decline, and notably with delayed recovery. This suggests that cognitive recovery from hypoxia may persist longer in older people.” Hey – I was only about 35 when this started! Nevertheless, the study concluded that “whilst cognitive performance improved on descent … it remained impaired when compared to pre-trek levels and even to those recorded at greater altitude on ascent. Thus, return to lower altitude does not immediately restore the cognitive effects of exposure to hypoxia.”

And there I reached the extent of the current research. HVR, acute organic brain syndrome, psychosis, old age, breath play; I hadn’t been able to determine the exact cause of my condition, but I guess the message is clear – do as much altitude as you can, while you safely can, because one day you might find yourself dangerously high in more ways than one, and cruising along at Care Factor zero.

Photos courtesy of the author. You can see more from Dan at his Instagram page, thisisnotaholiday.


Want to learn more about dealing with the physiological stresses of altitude? Check out Training for the Uphill Athlete: A Manual for Mountain Runners and Ski Mountaineers, by Steve House, a legend in the field.

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