The Young and the Rested
I overheard two teenaged girls chatting on the subway this morning.
“You look really tired,” one said.
“Yeah? I didn’t sleep at all last night and I’m exhausted. I feel old.”
And it turns out that not sleeping actually does make you old. According to researchers from the Duke-NUS Graduate Medical School in Singapore, there is evidence linking sleep duration to accelerated brain aging.
The study followed 66 Chinese adults, all of whom were at least 55-years-old. (Okay, so maybe it’s a slightly different demographic than teenaged girls in New York, but people are people, right?) Over the course of two years, participants subjectively rated their own sleep quality and duration and routinely underwent brain scans and cognitive function assessments to track ventricular growth and cognitive decline.
The ventricles of the brain are fluid-filled cavities that expand over time as the brain ages — so tracking the ventricles over the years will show brain age. It’s like counting the rings of a tree. Researchers found that “each hour of reduced sleep duration . . . augmented the annual expansion rate of the ventricles by 0.59 percent.” While that’s a small number, it adds up over the years. So the less you sleep, the more your ventricles grow, and your brain gets older, faster. Cognitive performance also fell by 0.67 percent.
The researchers concluded that short sleep is “a marker of brain aging.” So those girls I saw on the subway should rest up. If they don’t start getting their seven hours, they won’t just be feeling old — they will be 0.59 percent older.
— Josh Segal