This being the era of the space race, and just a few years after President Kennedy’s call to put a man on the moon, the subjects, researchers, and NASA alike saw the cave jaunt as a window in to what astronauts might experience on long, lonely space missions.

The experience was definitely trying. Upon her exit, Laures told the Associated Press:

I am so happy to have lasted it out, that I have forgotten everything. I can tell you though that it became very difficult toward the end and I felt terribly worn out … At the start of my stay I read, and then I lost the desire. I didn't suffer from the cold. I was well heated in my little tent. My tape recorder refused to work the first few days, but later I managed to repair it and I listened to music. Outside of that I knitted, and knitted some more, and looked forward to the time when I would finally see the sun.

But aside from that, the many old AP and Reuters articles I read about Senni and Laures didn’t say much about their physical and mental states post-emergence. Senni was apparently pronounced “in very good physical shape” by someone at the control point. And Michel Siffre, the speleologist who oversaw the experiment, told the AP that Laures was “in perfect health” after her stay, according to the hospital tests, though he noted that she had some temporary color-blindness, and trouble getting back to a normal sleep pattern, which does not sound perfect to me.

Later studies on isolation have found not only effects on sleep cycles but anxiety, hallucinations, and a decline in mental performance. These were sensory deprivation studies, though, and at least in the caves, the subjects were welcome to read or knit or listen to music.

Siffre’s isolation studies, of which Laures’s and Senni’s was but one, drew criticism as well as admiration.

“Some people think he is a bad boy,” the chronobiologist Franz Halberg told The Los Angeles Times in 1988. “But Siffre does what nobody else will do. He has, by far, the longest records of people in isolation. Others who have studied similar situations have done it for weeks; he has done it for months.”

Siffre also experimented on himself. In 1962, a couple years before Laures and Senni descended into their own stalagmite-studded holes, Siffre spent two months in a glacial cave in the Alps. Ten years later, in 1972, he did an even longer stint—six months in a cave near Del Rio, Texas.

“Physically it was not tiring, but mentally it was hell,” Siffre told the German magazine Der Spiegel, in 2014.

Siffre was so lonely in the Texas cave that he attempted to catch a mouse to keep as a pet. According to Der Spiegel, he spread jam on the floor of the cave, and while the mouse was licking it, brought a dish down over it to trap it. But he aimed poorly, and when he lifted the dish, the mouse had been crushed to death by the dish’s edge. “Desolation overwhelms me,” he reportedly wrote in his diary.

Laures, too, turned to rodents for friendship during her time in the cave, but with happier results. “A white mouse was her sole companion during the three-month ordeal,” the AP reported. “It came through the experiment in good shape.”