What’s it like to be sleep-deprived at 19,272 feet on a remote peak in the Peruvian Andes, rescuing a climbing partner who just took a nasty fall and is suffering from life-threatening pulmonary edema?
“When I thought about it afterwards, there were parts of it that didn’t make sense, particularly the timeline,” says Cordes. The pair did 23 rappels in the pitch dark and, although he was hallucinating the entire time, Cordes led the way, his partner drifting in and out of consciousness. “We knew when the sun rose that time of year, and we remember what time we stumbled back to our bivouac site below the route,” he says. The duo had lost about six hours of time; neither could account for them.
“I have no idea what happened,” he says. “We barely made it out alive.”
Few activities court more danger than high-risk, high-altitude mountaineering, where small teams hang out on vertical walls of ice and rock, living for days — or sometimes weeks — on end in order to summit sheer verticals. Top climbers like Cordes choose routes based on technical difficulty, aesthetics and remoteness, relying on strength, stamina and patience. Needless to say, getting a good night’s sleep is important; it’s also close to impossible.
First, much of the climbing takes place at higher altitudes where physiological changes conspire against rest. Second, it often takes place in the dark to avoid avalanches and rockfall, which are more common during the day. Third, biting winds and frigid temperatures can lead to exhaustion from hypothermia.
Finally, there’s the small issue of exposure. Safely securing oneself during a climb — and while preparing to sleep — is slow, deliberate, time-consuming work requiring a lot of mental energy. And much of the actual downtime (and sleep, when it comes) takes place in hammocks or ledges that have to be artfully supported thousands of feet above ground.
“The importance of sleep for human performance, both physical and mental, is crucial to climbing,” says Cordes, one of the world’s foremost mountaineers. His ascents include the planet's most remote corners, such as Cerro Torre on the Patagonia icecap, the aptly named Thunder Mountain in Alaska and deep in the Peruvian Andes.
“On big alpine routes that take multiple days to complete, getting a solid eight hours with a mint on your pillow is entirely unrealistic. So you learn to deal with fatigue, because you have to; if you don’t or can’t, then you go down. It’s complex and very simple at the same time.”
Sleeping at high altitudes alone harms sleep. The lack of oxygen not only fogs the mind, but also prevents the body from recovering in a normal fashion. (Dizziness, headaches, nausea and other signs of altitude sickness can start at 8,000 feet above sea level, and they only become worse the higher one climbs.) According to a 2001 report from Stanford University, “the result is a highly abnormal pattern of breathing during sleep at high altitude. When the brain senses low blood-oxygen levels, it forces the body to take three or four deep breaths.” These deep breaths result in a form of apnea. And the struggle is continuous: “When the blood-oxygen level again falls low enough, the cycle begins anew.”
As a result, mountaineers face impaired judgment, a drunk feeling and reduced physical strength. That's all in addition to the elements.
A renowned paraglider, ice climber and whitewater kayaker, Will Gadd grew up in the frigid shadows of Jasper National Park, where his father worked as a Parks Canada ranger. He echoes Cordes’ thoughts on sleep and has also dealt with deprivation over the years. His most important advice for fellow climbers: Be aware that your mind will get foggy, and be prepared.
“That takes really knowing your own mind and paying attention to what’s critical to your safety right now,” he says. “You have to live in the moment. No good is going to come from making potentially life-changing decisions when you’re barely hanging on.”
In other words — don’t ignore the mental struggle.
“I formulate what I call the Critical Importance Hierarchy,” says Gadd. “The first thing is recognizing how messed up you are. The second thing is knowing that a lot of really strange thoughts — even hallucinations — will invade your space, and you don’t want to pay any attention to them.”
Cordes has blogged about hallucinations in the past. For example, “On Nevado Ulta, little Peruvian men were talking to me as we climbed along the summit ridge where the ice rime can be notoriously dangerous.”
Another huge challenge that mountaineers face with sleep deprivation is that, especially if they’re cold and shivering, they simply never may wake up again. Early in his career, Gadd forced himself to stay awake while on a winter caving trip, recognizing that he was in the early stages of hypothermia.
Cordes admits he’s had many bivouacs (the climber’s name for camping outside without a tent or other adequate shelter) where he’s “floated between sleep and hypothermia,” trying not to shiver, which uses up a lot of your body’s energy. “I try to calm myself down by slowing my heart rate and my breathing,” he says. “But if I feel myself drifting off to sleep, I recognize that it’s getting dangerous, so I wake myself and do isometrics, or let myself start to shiver, or just pull myself back above that fuzzy line.”
Equipment can help. Climbers may carry oxygen tanks, and many carry caffeine in aerosol containers. But both Cordes and Gadd stick to a “light and fast” packing mentality; they limit the amount of gear they bring. To cut weight, Cordes doesn’t even bring a sleeping bag on most routes.
Ultimately, extreme fatigue is just part of mountaineering. As Cordes said, it's easy to find reasons to not climb the mountain. You have to fight through those excuses and fight through the sleep, learn to accept it.
“You have to go up more than you want to go down.”