(Mondial No.5, July 2017)
Athletes and adventurers are travelling further and further in pursuit of the extremes of human endurance. But what about the frontiers that lie within? RICHARD ASKWITH explores the mysteries of the exhausted brain
ON 1 JUNE 1933, Frank Smythe came within 300 metres of becoming the first person to climb Everest. The 32-year-old British climber had spent two nights camped in the “death zone”, at 8,351 metres; a fellow expedition member, Eric Shipton, had abandoned the attempt. But Smythe, “weak as a kitten”, staggered on for several hours, until he too could stagger no more. Confused and gasping for breath, he felt like a drunk driver. At one point, slipping, he nearly fell to his death. But he retained enough lucidity to realise, just in time, that he must turn back or die.
He stood for a while, swaying at “the very boundaries of life and death”. Finally, he summoned the will-power to move, and he and his remaining companion began, painfully, to descend.
Some time later, they stopped on a ledge for a rest and some Kendal Mint Cake. Smythe broke the bar in two and offered half to his companion – at which point he realised, with a shock, that he was alone. There had never been a companion – yet for all that time he had been convinced that someone else was walking beside him.
More than 80 years later, another young Briton found himself weak, cold and confused after more than 8,500 metres of ascent. But Alex Staniforth, a 21-year-old adventurer and writer from Cheshire, kept going. He had made two attempts on Everest before, each thwarted by lethal avalanches; for the second, three members of Alex’s party were among the dead. This time he was on safer ground. He was on tarmac, in Cumbria, on a bicycle, attempting to “Everest”, as the popular practice is known, by going up and down a single peak, far from the Himalayas, until he had completed the full 8,848 metres of ascent in single attempt.
The traumas of Alex’s previous attempts, on the real Everest, meant that this one, on Great Dodd Fell, was emotional as well as exhausting. He was accompanied for most of his 14-and-a-bit ascents, but by the time he approached the summit for the last time it was past 1am and he was alone. The darkness and fog were disorienting, the cold debilitating, the fatigue overwhelming. “I crossed the last cattle-grid and I was alone on the top. I stopped at the summit and sent a text to say I was on my way down. I felt elated, but it was eerie there as well. Then I felt a pat on my back – a quite distinct touch on my shoulder. It made the hairs on my neck stand up, and I headed back down at top speed. It didn’t really scare me, though. It felt warming, not threatening. It was only much later that I realised how strange it was.”
Exhausted humans have been having such experiences for as long as they have known the difference between reality and hallucination – perhaps longer. More than 2,500 years ago, the Athenian messenger Pheidippides, struggling to complete a marathon mission through 140 miles of rugged, sun-scorched Greek countryside, heard the god Pan calling to him from Mount Parthenium. Until recently, however, such experiences have been confined to those who, from necessity rather than choice, found unimagined reserves of endurance because the alternative was death.
Encounters with a “felt presence” are typically reported by explorers and climbers – Ernest Shackleton, Reinhold Messner, Stephen Venables, Joe Simpson, Doug Scott, Ann Bancroft – and soldiers. Airey Neave, the future politician, escaped from Colditz in 1944 and walked nearly 400 miles to Switzerland. He spent the final desperate push through the mountains chatting to a former colonel who wasn’t there. Three decades earlier, scores of British infantrymen reported visions, many involving angels, on their sleepless five-day retreat from the Battle of Mons.
Recently, though, something different has been happening. The ultra-runner Neil Bryant was enjoying an entirely self-imposed ordeal when, a few days into the 2014 Frostskade 500 (a 500-mile race through the wilderness of the Scandinavian Arctic), he encountered first a silent horseman in Victorian dress and then, crossing a frozen lake at night, a whole series of spectral observers. “I would see someone just ahead standing there watching me. As I got closer, he remained completely still. Then, as I would have bumped into him, I felt no resistance and passed through him.” A few metres later was another person, and then another, continuing for about 40 minutes. “Each person was very different and unfamiliar. No one was smiling. It all seemed really melancholic, but my curiosity at seeing the next face kept me going.”
It’s not just ultra-runners whose minds play tricks on them. When Gavin Lewis, a 37-year-old construction site manager from Llantwit Fardre, swam the Channel in September 2016, he was sure for much of the crossing that a large black fish was swimming alongside him – which with hindsight seems improbable. And Rapha-backed cyclist Ultan Coyle spent many miles convinced that he was being pursued by farm dogs while he was competing, of his own volition, in the 2015 Transcontinental race from Flanders to Istanbul (2,700-ish miles, solo, non-stop, self-supported, lasting, in Ultan’s case, 11- and-a-half days). “I could hear them panting just behind me and I knew they were chasing me.” Later, he concluded that the noise came from his sandwich wrapping.
Ask around among endurance sport enthusiasts and you’ll soon find examples. Not all involve a “felt presence”: many people see objects. Emma Mitchell – whose agonising struggle to row across the Pacific in 2015-2016 with the all-female Coxless Crew features in the documentary Losing Sight of Shore – saw “a big sailing ship coming towards us at speed” and wondered why her fellow oarswomen weren’t concerned. And Damian Hall imagined giant Chinese lanterns during his first attempt at the 268-mile Montane Spine Race (end-to-end of the Pennine Way on foot, in winter, sleep as little as you dare) in 2014. They were so convincing, and his sense that they were there to guide him so strong, that he went seriously off-course. “I was so grateful that people would come out at 4am into this remote and hostile place to light lanterns to show me the way. It didn’t dawn on me that they were hallucinations until much later.”
Endurance athletes have always been competitive when it comes to the discomforts of their sports. (“You think that was painful? You should see my groin…”) Today it sometimes seems that the new must-have sports misfortune is the hallucination. Unreal experiences reported by cyclists in recent Race Across America events – 3,000 miles coast-to-coast – have included attacks by bears, wolves, zombies, goblins, mail-boxes and gun-toting mujahideen. And in a study of the 2015 Ultra Trail de Mont Blanc (104 rocky miles, with 9,600m of ascent and descent), 56 per cent of runners reported visual hallucinations.
Going to extremes is fashionable – and fun. “People are travelling further and further, and more and more people are doing ultra-events,” says Mark Hannaford, founder of the Extreme Medicine group and chief executive of the Society of Extreme, Expedition & Wilderness Medicine. “A lot of what was deemed extreme 10 years ago now seems commonplace.” Bucket-list events go on for days, not hours; extreme environments are easier to get to than ever before. The adventure travel market has been growing by nearly 50 per cent a year for the best part of a decade.
Yet there’s a curious gap in this brave new world of recreational derring-do. In our hunger to test the limits of our endurance, we’re exploring further and further abroad. But what about what lies within?
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IT’S A tricky frontier to explore. There are plenty of case-histories, but most involve multiple stresses: not just muscular exhaustion but sleep deprivation, altitude, extremes of temperature and, in many cases, fear or danger. How do you replicate so many variables in a laboratory – let alone isolate their different contributions to specific mental states?
A few bold researchers have succeeded in studying brain function in the field. Dr Emma Ross, Head of Physiology at the Institute of English Sport, once strapped her equipment to the sides of Nepalese yaks. But each such adventure is unlikely to test more than one hypothesis, and there is always a risk that, in the words of Ron Maughan, Emeritus Professor of Sport and Exercise Nutrition at Loughborough University, “You go to a huge amount of trouble and expense to set something up, and then the thing you’re looking at just doesn’t happen.”
There are obvious obstacles, practical and ethical, to placing people deliberately in life-threatening situations. As to what you’d learn by doing so, there’s a catch. “It doesn’t much matter what you do to stress the brain,” Professor Maughan points out. “It responds to different threats and challenges in a remarkably similar way.” Factors that contribute to “cognitive stress” include hypoglycaemia (low blood sugar, resulting from muscular exhaustion); hypoxia (insufficient oxygen – typically resulting from altitude); dehydration; hyperthermia (over-heating); hypothermia (cold); and sleep deprivation. All produce much the same repertoire of symptoms: confusion, seeing things, hearing voices, lack of awareness.
The mass hallucinations reported at multi-day ultra events can be assumed to be mostly related to sleep deprivation. Even without physical exertion, 70 per cent of people are likely to hallucinate if they stay awake for long enough (ie, for up to 112 hours). These hypnogogic hallucinations can be compared to momentarily falling asleep. “It’s as if your mind is dreaming while you’re still awake,” is how Ultan Coyle puts it. “You’re in two worlds, merged together.”
The actual hallucinatory content seems largely random, although messages from the subconscious are sometimes discernible. Thus Damian Hall, lonely, exhausted and 5,000 metres up a mountain in Ecuador, “saw” a group of his friends having a picnic as he ran. (“I guess I was a long way from home and wanted to see familiar faces.”) And Felicity Aston, skiing alone across Antarctica for 59 days in 2011-2012, kept being tormented by the smell of fish-and-chips, which sounds like a classic case of wish-fulfilment. But polar environments are also associated with another kind of hallucination, based on sensory deprivation. If the senses can’t pick up enough information, the brain may fill in the gaps by guessing. Often, “hyper-vigilance” is involved: you’re so desperate for sensory input that you over- interpret the signals you do pick up. Thus the moon might become a Chinese lantern, or the rustle of some foil around some sandwiches the panting of pursuing dogs.
Muscular exhaustion may also be a factor. Lack of fuel, as supplies of brain glycogen run low, can cause neurons in the occipital cortex to misrepresent incoming images. But at least part of the explanation is likely to be lack of images. That’s why hallucinations are more common at night.
The “felt presence” is harder to deconstruct. The illusion can be created in the laboratory by applying electrical stimulation to an area on the left temporoparietal junction of the brain. That doesn’t explain why it occurs so often in near-death situations. Do multiple stressors cause the brain’s usual demarcation lines to break down? Without a decent supply of exhausted, confused adventurers who happen to be attached to brain scanners in their most desperate moments, it is hard to find out.
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WHAT WE can say confidently – with so many detailed accounts from intelligent, reputable people – is that, at extremes of exhaustion, danger and environmental stress, the mind can play tricks. Yet not every hallucination is real. When the British distance-runner Jim Peters was about to enter the stadium at the end of the Commonwealth Games marathon in Vancouver in 1954, he heard a spectator shout that his main rival had dropped out of the race. This meant that he had a huge lead and would win easily even if he walked the final 400 metres or so. But Peters, who was dehydrated, over-heated and already weaving all over the road, convinced himself, disastrously, that the voice he had heard was a hallucination. “You are being a coward,” he told himself. “You are just imagining he is out of the race.”
He began the final lap determined not to ease up. Eleven minutes later, still 200 metres short of the finish, he collapsed for the thirteenth and last time. He was in hospital for nearly a week and never raced again.
The story reminds us that, for those who experience them, the question of what hallucinations are is not just academic. They have to be dealt with. How? Experts urge caution. “Mental confusion is a big warning sign that something is very wrong which requires urgent medical attention,” says Tamara Hew-Butler, Associate Professor of Exercise Science at Oakland University. A keen distance runner, whose research methods include “lurking around the medical tents of endurance races”, she specialises in exercise-associated hyponatremia – in which, usually as a result of over-hydration, sodium levels in the blood become dangerously low. The result can be either cell shrinkage or cell swelling, either of which can cause confusion and either of which, in the brain, can be fatal. The best protection is to “drink only when thirsty and eat salt only to taste”, rather than try to outsmart the body by doing both to deliberate excess; and, if in doubt, to seek help. “The best advice – and what people don’t want to hear – is to listen to your own body and heed its warning signs.”
For many of us, unfortunately, not listening to your body is the whole point of ultra-endurance sport. Kirsty Reade, editor of Run247 and self-confessed running “obsessive”, fears that we have got into “a bit of an arms race” about how close to collapse we can push ourselves. “People wear these things like a badge of honour.” She herself has completed the Ultra Trail de Mont Blanc twice. Once she saw a centaur with the head of George Michael. The other time she was pulled over after appearing to be asleep as she ran and, after waking up, told marshalls that she had just been to the supermarket and would drive home in her car. She initially laughed at the experience, post-race, but was later advised that she might have been in the early stages of hypothermia and could easily have got herself into serious trouble. She now feels strongly that “If your body reaches a point where you start to experience hallucinations, it’s a sign that something isn’t going well. It’s a sign at least to have a rest.”
But where do you draw the line? One study of sleep-deprived athletes in the Ultra Trail de Mont Blanc found that impaired cognitive function – poor decision-making, slower reaction times – was twice as common as actual hallucinations. Yet even mild impairment has its dangers. Ultan Coyle blames his lack of sleep in the Transcontinental for a painful collision with a taxi in Bulgaria; and if you examine the (mercifully small) number of deaths that have occurred among mountain runners over the years, you’ll see that several have involved people having accidents after taking uncharacteristically poor decisions while confused – often from hypothermia.
Such tragedies should be off-set against the fact that, for most of us, the effects of the most extreme tests of endurance are overwhelmingly positive. Few thrills are so empowering as that of looking back at the end of an agonising ultra-endurance ordeal and realising that you have accomplished something that once felt impossible. “When you come back to your normal day-to-day life, and you come up against a problem, you’re quite sure that you’re going to be able to cope with it,” says Ultan Coyle. “You realise how strong you are,” says Emma Mitchell.
But do you sometimes wear yourself out as well? In June 2014, British fell-runner Steve Birkinshaw completed a continuous 320-mile circuit of all 214 peaks in Alfred Wainwright’s Pictorial Guides to the Lakeland Fells in six days and 13 hours, ascending and descending the equivalent of four-and-a-bit Everests – mostly on rough fell-side rather than recognisable trail – and knocking more than 12 hours off a 27-year-old record set by the legendary Joss Naylor. Hallucinations do not feature in his recently published account of his astonishing run, There Is No Map In Hell; there is, however, a disturbing post-script: for months after his record-breaking feat, Steve felt an overwhelming exhaustion, mental and physical. He calls it “brain fog”.
“It’s like trying to think through treacle,” he explains. “Just to type an email might take five minutes instead of one. It’s a bit like when you talk to a 100-year-old.”
According to his wife, Emma: “Sometimes I will ask him a simple question like ‘What time are you finishing work today?’, and it is as if I have spoken in a foreign language. If he was a car, he would probably need a new battery.”
For more than a year, Steve struggled with normal life. Three years on, he still doesn’t feel 100 per cent. Despite countless tests, he has no real sense of what caused the problem, beyond being certain that his Wainwrights run “definitely brought it on. I was fine beforehand and wasn’t after it. I have always ignored my body when it tells me to stop. Now it is clear to me that the abuse I put my body through has caught up with me.”
Could he be right? And, if so, could the brain be the means by which his body has taken revenge?
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IN 2009, from August to October, 67 ultra-runners took part in the Trans Europe Foot Race: a 4,487km road race from southern Italy to northern Norway. It was broken up into 64 consecutive daily stages, so sleep deprivation was not an issue. Physical exhaustion was. Forty-four of the runners took part in an exhaustive, day-by-day medical study, recording psychometric, body composition and biological measurements and daily sets of data from magnetic resonance imaging (MRI). Seven underwent repeated brain scans, before, during and after the race. The most startling finding was that, over the 64 days, grey matter in these athletes’ brains shrank by an average of six per cent. The usual rate of shrinkage is 0.2 per cent per year, so that’s equivalent to ageing 30 years.
Uwe Schütz, of the University Hospital of Ulm, speculated that the monotony of road-running might have something to do with his study’s findings. A simpler explanation would be chronic energy deficit, caused by two months of running 70 miles daily. Eight months after the race, brain size, like body weight, had returned to normal. There was no evidence of harmful after-effects, but the spectacular proof that extreme ultra-running does something to the brain whetted appetites for further study. As one researcher put it: “Having an understanding of what the brain does during an ultra-marathon event could… benefit not only endurance athletes but also military personnel… and patients affected by unexplained chronic fatigue syndromes.”
Today, the brain is one of the hottest topics in sports science. Most of the brain-power devoted to it is focused on improving performance. But understanding fatigue, and the brain’s role in it, is increasingly seen as a way of achieving that end.
The crucial concept is “central fatigue” – the idea that the limits of physical endurance are set not by the muscles but by the central nervous system. Supposedly exhausted muscles that are electrically stimulated directly (involuntary stimulation) are capable of more work than they are if they activated indirectly, by will-power or via stimulation of the motor cortex (transcranial magnetic stimulation). All other things being equal, “central fatigue” is greater than “peripheral fatigue”. Even in elite athletes, the brain quits before the muscles do.
“What you perceive as effort is not what’s going on in the legs,” says Professor Samuele Marcora, Director of Research at the University of Kent’s School of Sport & Exercise Sciences. “It’s the intensity of the brain activity necessary to keep your legs going. We call it central motor command.”
The mechanisms, purpose and even precise location of central fatigue remain only partially resolved. Hypotheses range from alteration of motor-neurone properties to exercise-induced metabolic changes. But not knowing exactly how it works does not prevent us from using what we do know to train the brain to unlock performance gains. Professor Marcora calls this the psychobiological approach.
Recent research has focused on which factors increase central fatigue. Dr Guillaume Millet, of the University of Calgary, has found that certain kinds of muscle damage – for example, from downhill running – seem to increase perception of effort in the motor cortex. Dr Stuart Goodall, working both at Northumbria University (where he is Senior Lecturer in the Sport, Exercise & Rehabilitation department) and in the mountains of Bolivia, has shown that altitude does the same, “causing the motor cortex to sub-optimally drive the quads”. Professor Marcora has shown that sleep deprivation has a similar effect, as does mental fatigue – for example, from performing complex calculations while attempting to train. The perception of effort may also be increased by stress or heat.
Such findings can be adapted into strategies to limit central fatigue: by modifying gait, for example, or making time to acclimatise; or by practising performing mental and physical exertions simultaneously. Professor Marcora has even devised a Brain Endurance Training programme to help athletes to do this. In one experiment, soldiers who used it improved their “time to exhaustion” three times as much as those who did not.
Such gains are impressive. For many of us, though, they are only part of the story. What really matters to us is not just performance but experience; and also, when we push ourselves to our utter limits, magic. Every endurance athlete has felt the euphoria produced by endorphins. Sometimes, too, we find ourselves in an altered mental state akin to meditation, especially when pushing hard. “I’ll go out and train, and I’m so focused on what I’m doing that all of the sudden the four hours has just gone,” is how Alexis Ryan, the Canyon/SRAM cyclist, describes it. “Nothing’s going on: there’s just the hum of the bicycle. I can’t even tell you what I thought about, because I didn’t really think of anything.”
And occasionally – usually when surrounded by natural beauty – the exhausted athlete experiences a sense of connection with the world that feels close to mystical: as when Emma Mitchell, rowing on a starry night between Hawaii and Samoa, “had a sudden realisation of how tiny we were and was quite at one with the ocean”. In such moments, says Damian Hall, “I can feel kind of reborn.”
There are known links between sustained exertion and the brain behaviour known as “transient hypofrontality”, in which the frontal cortex, which is associated with higher cognitive functions such as decision-making, temporarily loosens its grip. The same behaviour is associated with meditative states, so you’d expect similarities. What’s harder to explain is a rarer kind of magic, in which the athlete feels not only euphoric but also, in some dream-like way, unstoppable.
For Ultan Coyle, it came in the final stage of a Paris-Brest-Paris race: “For the final 300-400km, whatever happened, my body just switched into working really well. I could push harder and harder and harder on the pedals: your body becomes so efficient, it’s responding the whole time. I’ve never felt like that again, but it was amazing.”
For Neil Bryant, it came at the end of a 200km mountain race in Switzerland in which he had suffered badly nearly all the way, only to find himself flying up the final mountain. “I felt like I could go on for another 200km. I felt mentally wired, awake and happy. My energy levels were really high and there was no soreness in my muscles at all. I’ve done enough big races to know how the peaks and troughs come and go, but this was different. This was special.”
Professor Maughan, who was a top-class distance runner before he became a sports scientist, refers to such moments as “those days when you can’t keep up with yourself”. You’re unlikely to experience one if you haven’t devoted years of hard slog to your sport, but beyond that the causes are a mystery. “If only we knew,” he says.
“It may only happen to you once in a life-time. But that’s enough to keep you coming back for the rest of your life, hoping it will happen again.”