How much sleep do you need? It's all in the genes.

WRITTEN BY: Mia Wood

You know that phrase, “you can sleep when you’re dead”? It used to be a badge of honor to some, and an agonizingly unobtainable standard for others. Nowadays, experts say at least seven hours of sleep a night is crucial to your health. According to neuroscientists like Athena Akrami of University College London, that’s been quite a challenge during the COVID-19 pandemic. Not only do COVID patients experience insomnia and sleep apnea, for example, but even those who have not contracted the virus endure disrupted sleep. However, there are some people who seem to thrive on limited amounts of sleep. So, who are these seemingly magical people? Neurology professor, Ying-Hi Fu, says genetics hold the answer.

Fu and her colleague, Chris Jones, were leading a University of Utah research team working on familial connections among those with a rare sleep disorder when they happened upon something even more rare: Familial Short Sleepers. Fu recalls, "Nobody had any idea that our sleep actually can be regulated by genetics until we published [our] first paper [in 2001].”

The short sleeper is distinguished from the “morning lark” sleeper, who go to sleep around 7 PM — no matter how hard they try to stay awake — and awaken at around 2 AM. Fu and Jones were studying this group when they chanced upon a family with members who didn’t quite fit this pattern. The “short sleepers” didn’t go to bed early. Nevertheless, they woke up several hours later, just like the ‘larks.’

Fu and Jones then identified a gene mutation associated with a “short sleep phenotype.” This study led to a 2018 paper which showed that, in mice, a DEC2 gene mutation is responsible for longer waking periods. Later, at the University of California, San Francisco, Fu and her team found two more gene mutations associated with short sleep: ADRB1 and NPSR1. Not only did Fu and Jones found that short sleepers require far less sleep every night and experience no typical adverse health effects, like issues with memory. Later research showed that these short sleepers were also apparently benefiting from the situation, i.e. most short sleepers exhibit optimistic, outgoing, and type A personalities.

20 years after the original paper Fu and Jones published, sleep genetics researchers are thinking less about baseline sleep requirements for everyone, and more about individual sleep rhythm. So, while some people develop significant health problems when deprived of seven to eight hours of sleep per night, others thrive on no more than four or five — and even feel unwell if they get more than that.

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