For most of human history, people did not sleep in one continuous stretch. Instead, they practiced **two-segment sleep**, also known as **first sleep** and **second sleep**. Each segment lasted several hours, with a wakeful period of an hour or more in between, usually around midnight. Historical records from Europe, Africa, and Asia show that families would go to bed early after nightfall, wake around midnight, and return to sleep until dawn. During the midnight interval, people would tend to chores, pray, read, write, or spend time with family. This pattern disappeared over the past two centuries due to artificial lighting and the Industrial Revolution. Electric light shifted internal body clocks and allowed people to stay awake longer. Factory schedules encouraged single blocks of sleep. Today, brief awakenings at night are normal, but understanding this historical sleep pattern can help people feel less anxious about waking at 3am.
How Artificial Light Changed Our Sleep Patterns
The disappearance of two-segment sleep occurred over the past two centuries due to major societal changes. Artificial lighting played a key role. In the 1700s and 1800s, oil lamps, gas lighting, and eventually electric light turned night into usable waking time. People started staying up later instead of going to bed shortly after sunset. Bright light at night shifted internal body clocks, known as circadian rhythms, making bodies less likely to wake after a few hours. The Industrial Revolution also transformed sleep habits. Factory schedules encouraged a single block of rest. By the early 20th century, eight uninterrupted hours became the standard, replacing the centuries-old rhythm of two sleeps.
Understanding Modern Sleep Struggles
Sleep experts note that brief awakenings are normal and often occur during sleep stage transitions. What matters is how people respond to these awakenings. Without the historical pattern of getting up and doing something during the night, waking at 3am can make time feel slow and cause anxiety. The brain's sense of time is elastic, with anxiety and low light making time stretch. Cognitive behavioural therapy for insomnia advises leaving bed after about 20 minutes awake, doing a quiet activity in dim light, then returning when sleepy. Sleep experts also suggest covering the clock and accepting wakefulness calmly, which may be the best way to rest again.
Source: Original report