From the evolution of sleep habits to modern day sleep trends, a report from The Huffington Post examines sleep habits over time and how we think about sleep today.

Americans’ complicated relationship with sleep is no secret. According to the CDC, about 9 million of us use prescription sleep aids. But mainstream sleeping hours could be partly to blame. That eight-hour golden rule we all strive for? It just might be wrong. Think about it: People live in wildly different ways, and yet insist on conforming to the same sleep routine. It’s no wonder that so many of us can’t seem to win at sleep.

But don’t hide under the covers just yet, because there could be a better approach. It’s worth taking a look back at the work of sleep researcher Thomas A. Wehr, who subjected people to 14 hours of daily darkness for a month in the 1990s. And you thought the end of daylight saving time was harsh!

As Wehr’s study progressed, something odd happened. Instead of sleeping for several hours straight, subjects began sleeping in two blocks, each about four to five hours long. In between, they lay peacefully awake for up to a few hours — not quite what most of us experience these days when we jolt awake at 2 a.m. Follow-up research revealed why: Extended darkness triggered a release of the calming hormone prolactin and the sleep regulator melatonin; the perfect marriage for a meditative middle-of-the-night state.

What Wehr had “discovered” — the so-called biphasic pattern of sleep — was actually nothing new or revolutionary. As far back as 800 B.C., humans slept in two separate spans of time, between which wakefulness was considered perfectly normal. History is no stranger to segmented sleep: it’s relevant everywhere from The Odyssey to 16th-century prayer manuals. In fact, one historian has identified nearly 500 historical references to biphasic or “segmented” sleep.

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