There are clocks in our other tissues too, and these are usually kept synchronised with each other by the SCN. If their timing becomes confused – as it would if you were trapped underground – then these other clocks may also become confused. Such circadian disruption has been linked to depression, insomnia, metabolic and hormonal disturbances, and impaired concentration.
Yet there is an antidote. When 33 miners became trapped in a Chilean copper mine for 69 days in 2010, special ‘circadian lighting’ was sent down to try and replicate the natural light/dark cycle outside. A similar strategy might be used in Thailand: if the artificial light used during the daytime is bright enough, this can trick the SCN into resetting itself, enabling it to synchronise with the outside world and keep the rest of the body on time.
Linda Geddes is the author of Chasing The Sun: the astonishing science of sunlight, and how to survive in a 24/7 world, which will be published by Wellcome Collection in January.
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