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Adventurer in time An extraordinary experiment on himself showed Michel Siffre that the body does have its own clock. Laura Spinney went Spinney went to meet him
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N JULY 1962, Michel Siffre took off his watch and descended into the abyss of Scarasson in the French Alps. There, in a cave 130 metres below the surface, he set up camp next to a glacier. With a torch as his only light source, and deprived of all reminders of the passage of time, he lived underground, alone, for 63 days. When he emerged, wearing goggles to protect his eyes from the sun, the world’s press was waiting. Siffre was a geologist, but what he had originally planned as an expedition to study the glacier had become famous as something completely different: the first study of the human response to living with no information about time. Siffre was the first to show that our body might have its own clock. Since then, chronobiology has become a hugely important field of research. Now nearly 80, Siffre lives alone in a small apartment in Nice. It is so crammed with souvenirs, including giant fossil ammonites, that it resembles a cave itself. A ball of energy despite his age, he apologises for the disorder, although everything here, from the framed photos of his exploits to climbing equipment hung on the wall, demonstrates how this energy has been a defining feature of his life. As he shows me a tube of the electrode paste used on Apollo missions, he describes how the space race was his inspiration. Yuri Gagarin had just become the first man in space and the US and USSR wanted to know what effect long lo ng missions would have on astronauts. Without seeing day and night, it was assumed, a human would continue to function according to a 24-hour cycle, but that assumption had never been tested. Siffre decided to test it himself, although for the 23-year-old it was as much an adventure in timelessness as a scientific trial. “I was a geologist, not a biologist. biologi st. I raised 40 | NewScientist | 11 August 2018
Michel Siffre lived underground three times: first in France in 1962, then Texas in 1972 (right) and finally back in France in 2000 (left)
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the funds myself, picked the two months arbitrarily and invented the experimental protocol,” he says. In the cave, Siffre’s only connection to the world was a phone line to a camp on the surface, and someone was always there to answer it. He called on waking and before going to sleep, passing on information such as his pulse rate and temperature. His collaborators were instructed not to give him the slightest temporal clue.
Human dynamo His camp was on a small area of flat rock at the foot of the glacier. There was barely space to walk around. He passed the time thinking and reading the memoirs of Charles de Gaulle. Was he lonely? “Not really,
though I missed my girlfriend,” girlfr iend,” he says. “But I was 100 per cent motivated. mot ivated. I was a human dynamo.” The experience was physically harrowing, nevertheless. It was 3°C in the cave, and condensation pooled on the floor of his tent so his feet were permanently wet and cold. Worse, Worse, lumps of ice and rock would periodically fall from the glacier and crash nearby, terrifying him. After one particularly hair-raising rock fall, he stayed on the phone for more than 10 hours, though it didn’t seem that long to him. His perception of time had changed: “Two seconds passed, I perceived one.” He kept a diary. The experiment was due to finish on 14 September, Sep tember, but on what he estimated to be 20 August he learned his time was up. He was 25 days out.
by lightning that travelled down the cable connected to the electrodes on his body, giving him a violent jolt. Psychologically, however, Midnight cave took a terrible toll. Three months in, he cracked. Overwhelmed by a feeling that he was wasting his time and betraying his vocation, he ripped the sensors off his body. But he didn’t ask to leave the cave, and he carried on doing the cognitive tests. After 10 days, a sens e of duty made him connect himself back up again. “But from then on the cave became my prison,” he says. If it hadn’t been for an iron will – his philosophy of marche ou crève (which translates as walk or die) – and a small female rat he befriended, he is convinced he wouldn’t have completed the experiment. In Midnight cave, Siffre’s sleep-wake cycle
“His perception of time had changed: ‘Two seconds passed, I perceived one’ ”
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He emerged exhausted, but with his spirit intact, although there were some temporary after-effects. He would play the same record over and over again, forgetting that he had just heard it. Not much is known about the effects of timelessness on memory, but Siffre has his own explanation: “You’re a point of light in a permanent darkness,” he says. “The brain grasps no time because there is no time. Unless you write down what has happened, you forget it immediately.” It wasn’t only his perception of time that had changed. In the cave, his sleep-wake cycle had increased to 24 hours and 30 minutes. He had gone to sleep and woken a little later ea ch day, until he had become nocturnal. It showed, Siffre said, that the body had its own clock. But scientists didn’t accept that idea easily. “They thought I was mad,” he says.
Over the next decade, he oversaw a series of experiments in which other volunteers went without time cues for up to four months. These demonstrated that the body’s clock could be extended into a 48-hour cycle, something Siffre hadn’t achieved in Scarasson. That was one reason why, in 1972, he decided to test himself again. He had another motive: “People were whispering that I was happy to send others down, but not myself; that after Scarasson, I was afraid.” This time he spent six months underground in Midnight cave in Texas – the longest period of timelessness anyone had attempted to date. Technology had moved on since 1962. Electrodes stuck to his scalp and body monitored his physiological activity, and he performed daily cognitive tests. There were no physical threats, though he was once struck
stretched more slowly than it had in Scarasson, but it stretched further, and he twice achieved a 48-hour cycle. But he also got depression, which lasted for many months after leaving the cave. It wasn’t helped by his financial situation: he had been obliged to foot the bill when funding ran out. “I was broke,” he says. He went off to explore cave formations in Guatemala, and it was only in 2000, after learning that the 77-year-old astronaut John Glenn had returned to space, that he decided to undertake one last adventure in chronobiology. Now 60, his aim was to explore the effects of ageing on the body clock. After two months in a stalactite-encrusted cave near Montpellier, France, he found that his sleep-wake cycle evolved as it had in his 23-year-old self. Siffre’s investigations launched a line of study that culminated in a Nobel prize in 2017 for the three researchers who identified the genes governing what we now know to be multiple body clocks. It contributed to the invention of light therapy for mood disorders and drugs for jet lag. Revisiting those experiments, however, it is difficult not to be struck by how biomedical ethics has moved on. None of the many organisations that supported Siffre’s research questioned the ethics of it, or offered him psychological support. But then, Siffre expected nothing more. Surrounded by memories of a life richly lived, he says, “ Je ne regrette rien.” ■ Laura Spinney is a writer based in Paris 11 August 2018 | NewScientist | 41
