Your Great-Grandparents Slept Twice a Night. Your Body Still Wants To.

The Sleep Pattern Nobody Talks About

In 1595, a French doctor named Laurent Joubert wrote something peculiar in his medical text: he described patients waking in the middle of the night, fully alert, often getting out of bed to tend to household tasks or visit neighbors. He didn't frame this as a disorder. It was simply how sleep worked.

Fast forward to the 1600s in England, and the pattern appears in literature, diaries, and medical records with striking regularity. People went to bed after dark, slept for three to four hours, then woke during what they called "the watch" or "the first waking." During this wakeful interval—sometimes lasting an hour, sometimes two—they'd read, pray, write letters, have intimate conversations with their spouse, or simply lie in bed thinking. Then they'd return to sleep for another three to four hours until morning.

This wasn't insomnia. This wasn't a problem. This was simply sleep.

Historians and sleep researchers now have a name for it: segmented sleep, or biphasic sleep. And the evidence suggests it was the dominant sleep pattern across Europe, North America, and likely much of the world for centuries. Legal documents reference it. Novels depict it without explanation. Medical texts treat it as normal variation. The night wasn't one long dark period—it was structured into distinct phases, with a wakeful interlude built into the architecture of rest.

What Changed Everything

The transformation happened almost entirely within the span of a single century, beginning in the late 1800s and largely complete by the 1920s. The culprit: electric light.

Before reliable artificial lighting, nightfall meant darkness. Staying awake after sunset required candles or oil lamps, both expensive and inefficient. So the rhythm of sleep followed the rhythm of light. You slept when it was dark, and darkness came early. Segmented sleep fit naturally into this world—you could wake in the middle of the night without disrupting anything, because the night was long and darkness was expected.

But electric light changed everything. Suddenly, darkness was optional. You could stay awake and productive through the entire night if you wanted to. The value of darkness diminished. Industrial society needed continuous productivity. Factory shifts ran around the clock. The idea that sleep should be consolidated into a single uninterrupted block became the new ideal—it was more efficient, more aligned with work schedules, more modern.

And so, within a remarkably short time, people simply stopped sleeping in two phases. By the 1920s, segmented sleep had virtually disappeared from Western culture. Medical texts stopped mentioning it. Diaries no longer recorded it. The new norm—eight hours of continuous sleep at night—became so universal that people forgot the old pattern had ever existed. By the time modern sleep science emerged in the 1950s, biphasic sleep was already a historical curiosity, not a living practice.

What Modern Sleep Science Is Discovering

Here's where it gets interesting: in 2001, sleep researcher Roger Ekirch published his findings on segmented sleep, based on extensive analysis of historical documents. His work prompted a wave of new research into sleep patterns and what our bodies actually want.

What emerged was surprising. When people are placed in conditions of extended darkness—like a 14-hour night—they naturally revert to biphasic sleep. They'll sleep for four hours, wake for an hour or two, then sleep again. It happens without instruction. It happens across age groups. It happens even in modern people raised entirely on consolidated sleep.

Sleep researcher Thomas Wehr conducted a famous experiment in the 1990s where participants were given 10 hours of darkness each night. Within weeks, they shifted to segmented sleep, sleeping approximately four hours, waking for one to two hours, then sleeping again. During the wakeful period, their bodies showed elevated levels of prolactin, a hormone associated with relaxation and meditation. They weren't anxious or frustrated. They were calm and contemplative.

This suggests something radical: the consolidated eight-hour sleep block might not be what our bodies naturally prefer. It might be what our schedules prefer. Our biology might still be wired for the old pattern.

The Insomnia Epidemic Nobody Expected

There's a strange correlation worth noting. Sleep problems in America have exploded in the past 50 years. Insomnia diagnoses have skyrocketed. Sleep medication use has become normalized. Roughly one-third of American adults now report regular sleep difficulties. We've built an entire industry around fixing our broken sleep.

But what if the problem isn't broken sleep? What if it's a mismatch between what our bodies expect and what our schedules demand?

Consider the person who wakes at 3 a.m. and can't fall back asleep. Modern medicine frames this as a problem—a symptom of anxiety, stress, or sleep disorder. But to someone living 200 years ago, this would have been the expected wakeful period. The difference is context. They had a framework for it. They knew it would pass. They had activities suited to that quiet time.

Today, we lie in bed panicking, checking our phones, wondering what's wrong with us. We take medication to prevent it. We treat it as a failure.

The Practical Question

None of this means you should try to force yourself into segmented sleep. Modern life doesn't accommodate it. Jobs start at 9 a.m. Schools run on schedules. The infrastructure of contemporary society is built around consolidated nighttime sleep and daytime productivity.

But understanding the history matters. It reframes the conversation. When you wake at 2 a.m. and can't immediately fall back asleep, you're not necessarily broken. You might be experiencing what your body still expects—a natural part of how humans have slept for most of history.

Some sleep researchers now suggest that rather than fighting middle-of-the-night wakefulness, we might benefit from accepting it. A 20-minute meditation. Reading. Quiet time. Rather than treating it as a problem to solve, treating it as a natural rhythm to accommodate.

It's a small shift in perspective, but it reflects something larger: the sleep pattern we consider normal is actually quite new. Our bodies might still remember something older.