History shows humans once slept twice a night — here’s why we don’t anymore

If you regularly wake at 3am and stare into the dark wondering what’s wrong, you’re not alone, and you may not be broken. For much of human history, sleeping straight through the night wasn’t the norm. The idea of eight uninterrupted hours is surprisingly modern.

Before electric lights and factory schedules reshaped daily life, people commonly divided their nights into two distinct sleeps, and thought nothing of it.

ALSO READ: Employee wants to vent ire at exit interview and name people for what they were up to — gets advice to calm down

Did humans really used to sleep in two shifts?

For centuries, people across Europe, Africa, and Asia followed a pattern often described as “first sleep” and “second sleep.” After nightfall, families would go to bed early. Several hours later, they would wake naturally for an hour or more before returning to bed until dawn.

Historical letters and diaries show that this middle stretch of wakefulness was ordinary. It wasn’t restless tossing and turning. It was expected time, noticed time, that gave the night a clear midpoint. Long winter evenings felt less endless when broken into two manageable parts.

During that quiet interval, some people rose to stir the fire or check on animals. Others remained in bed to pray or reflect on dreams. Many used the calm darkness to read or write. Some even visited neighbours or spoke softly with family members. For couples, the midnight waking was often a time for intimacy.

References to this pattern appear far back in literature. Ancient Greek poet Homer and Roman poet Virgil both mention an “hour which terminates the first sleep,” showing just how common segmented sleep once was.


ALSO READ: Employee takes WFH within a week of joining without informing boss on an overseas business trip - Internet says she crossed boundaries

How did artificial light and industry change sleep?

The disappearance of the “second sleep” unfolded over the past two centuries. As oil lamps, gas lighting and eventually electric lights extended the evening, people stayed awake later. Instead of going to bed shortly after sunset, nights became productive time.

Bright light after dark does more than help us see. It shifts our internal clock, the circadian rhythm, and reduces the likelihood of waking naturally in the middle of the night. Even typical room lighting before bed can delay melatonin release, pushing sleep later, as per a report by Science Alert.

Then came the Industrial Revolution. Factory work encouraged strict schedules and a consolidated block of rest. By the early 20th century, eight continuous hours in bed had replaced the older rhythm of two sleeps.

Yet when researchers recreate long winter nights in sleep laboratories, removing clocks and artificial evening light, many participants naturally drift back into two segments of sleep with a calm waking period between them.

A 2017 study of a Madagascan agricultural community without electricity found people still tended to sleep in two blocks, often waking around midnight, as per a report by Science Alert.

Why does light shape how we feel about time and sleep?

Light is more than illumination; it anchors our sense of time. In winter, weaker and later morning light makes circadian alignment more difficult. Morning light contains higher levels of blue wavelengths, which are especially effective at stimulating cortisol and suppressing melatonin, as per a report by Science Alert.

Without strong light cues, whether in caves, time-isolation laboratories, or polar winters, people often lose track of passing days. Many miscount time entirely. In places with prolonged darkness, time can feel suspended.

Research also shows mood plays a role in how we experience time. In virtual reality experiments matching scenes from the UK and Sweden, participants viewed short clips set at different times of day and light levels. Two-minute intervals felt longer in evening or low-light scenes than in bright daytime ones. The stretching of time was most noticeable among participants reporting low mood.

This elasticity of time perception matters at 3am. Anxiety and low light can make minutes feel drawn out. Without a cultural expectation of a natural midnight interval, people often focus on the clock — and the longer they watch it, the longer the wakefulness seems.

Is waking at 3am actually normal?

Sleep clinicians note that brief awakenings are common, especially around stage transitions and near REM sleep, which is linked to vivid dreaming. What often determines whether it becomes distressing is our reaction.

Cognitive behavioural therapy for insomnia (CBT-I) recommends getting out of bed after roughly 20 minutes awake and doing a quiet activity in dim light, such as reading, before returning to bed when sleepy. Experts also suggest covering the clock and letting go of time tracking during the night, as per a report by Science Alert.

Understanding that segmented sleep was once typical can shift perspective. Waking in the night is not necessarily a malfunction. In many ways, it is a deeply human pattern that modern life compressed into a single block.

ALSO READ: Quote of the Day by Maya Angelou: 'There is no greater agony than bearing…'—Inspiring quotes by the world-famous author

FAQs

Did people really wake up in the middle of the night on purpose?
Yes. Historical records show many expected a natural waking period between a “first” and “second” sleep.

Why do we sleep in one block now?
Artificial lighting and industrial work schedules gradually replaced segmented sleep with a single, consolidated eight-hour pattern.