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. 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