Be somnological

That Margaret Thatcher slept only four hours a night was a famous pillar of her Iron Lady persona. This “sleep is for wimps” brag is a hoary one. Napoleon made it too. And yet, when Sanae Takaichi X-ted that she’s only been taking 0-3 hours of sleep since becoming Japan’s PM, it didn’t come across as a badge of honour. Because, times they are a-changin’. Leaders who can’t “switch off” are now a red flag, because science no longer sees sleep as simply “switching off”.

The brain consumes about 20% of the body’s energy, when asleep, as much as when awake. A whole glymphatic system has been discovered, which really only works in the zzzzzz state, building memory and plasticity.

Basically, every night, your brain deliberately disconnects you from the outside world so it can do maintenance on the inner one, honing the very capacities that make you you . Literature told us this regeneration story long before science. Shakespeare called sleep “balm of hurt minds”, Homer sang about “sweet slumber”.

What our ancestors couldn’t have known is how sleep has become a socioeconomic and climatic matter. India’s largest cities are seeing people lose 65-93 hours of sleep each year, as nighttime temperatures rise. Shift work is playing hell with circadian clocks. Air-conditioning is also separating the have-sleeps and haveno-sleeps. Other inequalities rise on top of this one. Because poor sleep is linked to a range of health concerns, from heart disease to depression. In animal studies, it hastens disease and death.

But back to Thatcher, Takaichi, and Napoleon. Maybe they are among the people genetically gifted to need less sleep. Even “owlness” and “larkness” are determined by genetics. Matthew Walker proposes in Why We Sleep that this variability is because humans evolved to co-sleep as families, or even whole tribes, not alone or as couples. But today’s main truth is that sleep has become a collective want, much like clean air or safe drinking water. And politicians should note how elite footballers hire sleep coaches for enhancing performance. “I only slept four hours” is old school. “I protect my sleep” is much the cooler status update.

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