In his later life, my father-in-law routinely woke up for the day at 3 a.m. He'd become such an early bird that he morphed into a night owl, a man resigned to a post-retirement inability to clock in more than four or five hours of rest. I can recall taking his routines as a grim prophecy. And when a few years later I found myself struggling with brutal bouts of insomnia, I wondered if, along with laugh lines and macular degeneration, sleeplessness was an inevitable part of growing older for me, too.
There is a persistent folk wisdom that older people simply don't need as much sleep — an idea likely borne out of the idea that as our lifestyles ostensibly become less active, our requirements for the reparative benefits of rest diminish. As recently as 2008, a report in Current Biology found that in one experiment, older subjects got 1.5 hours less sleep on average than their younger counterparts. "The most parsimonious explanation for our results," researcher Elizabeth Klerman of Brigham and Women's Hospital & Harvard Medical School said at the time, "is that older people need less sleep."
