Before electricity, humans slept twice a night; scientists explain why biphasic sleep made perfect sense

Before electricity and endless screen time took over, humans followed a very different rest routine. In the pre-industrial world, people didn’t sleep in one uninterrupted stretch but in two distinct phases known as first sleep and second sleep. Between these two rests, they often stayed awake for an hour or two, praying, reading, or quietly reflecting. This older form of biphasic sleep was not a sign of insomnia but a natural way of living that matched the body’s rhythm before modern life reshaped our nights. Understanding this pattern today can help improve sleep quality, reduce stress, and inspire more mindful nighttime routines aligned with natural circadian rhythms.A peer-reviewed study in the Journal of Sleep Research (2018) found that exposure to artificial light disrupts the circadian rhythm by delaying melatonin secretion, the hormone that regulates sleep cycles. Researchers concluded that electric lighting and evening activities were major factors behind the disappearance of segmented sleep in industrialised societies. Biphasic sleep, also known as segmented sleep, was the typical pattern for centuries across Europe, Africa, and parts of Asia. People would go to bed shortly after sunset, sleep for about four hours, wake up around midnight for quiet activities, and then return to bed for their second sleep, often engaging in prayer, reading, reflection, or intimate conversation before resting again until dawn. During this middle-of-the-night period, households were often lit by candles or lamps, and people sometimes tended to chores, wrote letters, or contemplated personal and spiritual matters, embracing a natural rhythm that modern society rarely experiences today.During this in-between period, people might tend to the fire, talk, write, meditate, or even visit neighbours. Far from being considered restless or unhealthy, this night-time wakefulness was seen as peaceful and restorative, a natural pause between two halves of rest, encouraging reflection, creativity, deeper connection, and a sense of calm before returning to sleep. Modern research suggests that incorporating quiet, intentional pauses like this can improve mental clarity, reduce anxiety, foster creativity, and help maintain a healthier balance between activity and rest throughout the day and night. Such historical rhythms remind us that rest can be flexible, intentional, culturally shaped, and supportive of more sustainable human wellbeing. Before electricity, human sleep patterns were deeply synchronised with the sun’s rise and fall. The circadian rhythm, our internal biological clock, follows the natural light-dark cycle, allowing melatonin to be released soon after dusk. This hormone signalled the body to wind down, making early sleep feel natural. Without artificial lighting or screens, evenings were calm and quiet, encouraging rest, reflection, and connection before drifting into restorative, uninterrupted sleep that aligned perfectly with nature’s rhythm, supporting physical repair, mental clarity, emotional balance, and overall health in a way modern lifestyles with artificial light often struggle to replicate consistently.When artificial light and late-night work became common, this delicate cycle shifted. Studies show that exposure to bright lights in the evening suppresses melatonin production, keeping people awake longer. As bedtime moved later, the natural window for first sleep disappeared, merging both sleep segments into the single, continuous stretch we know today. This shift altered human rest patterns, reducing quiet nighttime reflection and reshaping how people recover and regulate energy throughout life.Historical records, court transcripts and personal diaries from the 15th to 18th centuries reveal that segmented sleep was a widely accepted and normal nightly routine rather than an odd exception. Historian Roger Ekirch’s extensive research uncovered hundreds of documented references to first sleep and second sleep across Europe and beyond, demonstrating clearly that it was not limited to one culture or social group but instead reflected a broad human practice. These findings strongly suggest that modern consolidated sleep patterns are a relatively recent development shaped by artificial lighting, industrial work schedules and major cultural shifts during the modern era. Rather than representing a universal biological standard, today’s continuous eight hour sleep block appears to be more of a contemporary adaptation than the historical norm, reshaping our understanding of natural human sleep behaviour across centuries.This middle-of-the-night interval was often used for relaxation, quiet contemplation, reflection, and even creative thinking or problem-solving in solitude. People valued the profound silence and calm darkness, treating the period between sleeps as a meaningful opportunity for spiritual, personal, or emotional reflection. Unlike today, waking up at 2 a.m. wasn’t a cause for alarm or disruption, it was a familiar, natural, and even cherished part of daily life, offering moments of peace and introspection that modern schedules often overlook. The Industrial Revolution changed everything. With factories, gas lamps, and later, electric lights illuminating city streets, people stayed awake longer. Work schedules demanded consistent hours, forcing society to compress rest into one continuous block.As artificial light delayed the body’s melatonin release, natural cues for sleep weakened. Modern stress, caffeine, and irregular routines further disrupted the circadian rhythm. Within a century, the biphasic sleep pattern that had defined humanity for millennia nearly vanished, replaced by the modern monophasic sleep cycle.If you often wake up in the middle of the night, you’re not necessarily struggling with insomnia; it might be your body echoing ancient sleep rhythms. Sleep scientists explain that brief periods of wakefulness between sleep cycles are natural. What’s changed is how we interpret them, as modern lifestyles, stress, and artificial light have disrupted our natural circadian patterns, making these awakenings feel abnormal or problematic.In the past, people saw night-time wakefulness as an opportunity for reflection or rest. Today, we panic about it, turning a normal biological rhythm into anxiety-driven insomnia. Understanding this connection between segmented sleep and circadian rhythms can help normalise such awakenings and reduce unnecessary sleep stress. By reframing these moments as natural pauses rather than disruptions, we can restore a healthier relationship with sleep, one that values balance, patience, and the body’s ancient rhythms.Some people are revisiting biphasic sleep to match flexible work hours or natural energy patterns. They find that dividing sleep into two sessions, one longer at night and a short nap or second rest, can enhance focus and alertness.While results vary, small studies suggest that allowing the body to follow its natural cycles improves mood and cognitive function. Still, most sleep experts recommend consistency: a regular sleep-wake schedule supports melatonin balance better than fragmented rest.Our ancestors’ segmented sleep patterns reflected a slower, more organic lifestyle in sync with nature. Modern life compressed those rhythms into a single block, making us forget the body’s natural ebb and flow. But traces of biphasic tendencies remain, in brief night awakenings, early-morning calm, and the drowsiness that hits mid-afternoon.Reconnecting with these patterns doesn’t mean abandoning modern schedules. It means understanding that sleep is adaptable, not one-size-fits-all. Whether you rest once or twice a night, the key lies in respecting your circadian rhythm and creating an environment that supports it. True rest, after all, comes not from the number of hours you sleep, but from how closely your body aligns with its natural rhythm.In the end, biphasic sleep reminds us that rest has always been more about rhythm than routine. 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