The post-apocalyptic series Silo immerses us in a frightening fiction: to survive an air that has become toxic, human beings must recreate a society… entirely underground. But could we survive without seeing sunlight? We asked the question to Dr. Joathan Taieb, doctor at the Medical Institute of Sleep in Paris.
Living underground to avoid threats, be they toxic, alien, or even led by a horde of zombies, is a fantasy that often comes up in SF literature and among survivalists. Silo, a new series on Apple TV, is the latest to consider such a change: in a future where the Earth is devastated and the air becomes toxic, the survivors then live in a silo underground giant of 144 floors. Enough to imagine many adventures and distressing situations. But in reality, is it possible? Can we live sustainably without sunlight?
An inevitable jet lag
Consulted on the subject, Dr. Jonathan Taieb, a sleep specialist, explains to us that this decision would impact our circadian rhythm quite quickly, as demonstrated by the various “out of time” experiments carried out on the subject for decades.
“What you need to know is that we as humans have a biological clock that differs a little from the earth’s rhythm. Which is 25 hours and not 24 hours. Therefore we need spatiotemporal markers on a daily basis , so that we can constantly readjust and re-synchronize ourselves with the environmental rhythm. Benchmarks such as social contacts, food, but above all light. Without light, our clock gets out of sync and our rhythm can only become irregular. Our sleep, our food would lose quality” he explains to us. In fact, the scientists who carried out this type of experiment, no longer knew how to count the days, the hours of sleep and would find themselves having breakfast at 11 p.m….
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Cascading negative reactions
In addition to this curious jet lag, the doctor details what a desynchronization would imply on the human body. And the effect is not very enviable. Above all, we think of vitamin D, synthesized by sunlight, itself essential for the proper absorption of calcium responsible for the strength and health of the bones. Years underground would undoubtedly increase the risk of osteoporosis. But this is not the only effect to be feared:
“We have photoreceptors in the retina that capture the light signals that send messages to our biological clock from morning to night. But the lack of light will completely mess up this clock’s ability to regulate mood and health. It is our biological clock which imposes for example the secretion of several hormones, cortisol which will allow us to be alert in the morning, melatonin which promotes sleep, serotonin… Without forgetting that light also acts on the cerebral areas involved in depression. Underground, not only would we be plagued by many deficiencies, but also, without a doubt, by strong anxiety disorders, all linked to the lack of light.”
Would we survive such changes? Not sure, even if it is not necessarily possible to know with certainty. But without sunlight, there’s a good chance we’ll fall into depression, or even go mad before we physically succumb.