Did Humans Get More Sleep Before the Light Bulb?
The conversation around human sleep patterns often centers on the idea that we sleep differently since the advent of artificial lighting. The evidence, however, suggests that our sleep habits have varied widely based on seasons, circumstances, and cultural practices throughout history.
Changing Sleep Patterns Throughout the Seasons
In the summer, humans might have experienced a single sleep session due to the extended daylight hours and shorter nights. In contrast, during the winter in more temperate regions, middle-class individuals in Europe often divided their sleep because of the longer, darker nights. However, there are fewer records of this practice in Asian cultures. Similarly, in many countries where work or leisure activities are conducted during the day, individuals would sleep once at night.
Rights and Responsibilities Before the Light Bulb
Although the invention of the light bulb changed the game, it is often forgotten that many ancient civilizations had methods to extend their waking hours beyond the natural darkness. Neolithic humans, for instance, discovered the controlled use of fire for cooking, warmth, and protection from predators. While the availability of fire or gaslights likely influenced sleep patterns, it does not mean that prolonged darkness necessitated long or fragmented sleep sessions.
The Quality of Sleep, Not the Quantity
Recent studies on primitive societies, such as the tribes in Namibia, Tanzania, and Bolivia, have shed light on the quality of sleep rather than the quantity. These groups, who lived without modern conveniences including electricity, followed a natural rhythm dictated by the sun. They typically stayed awake until sunset and woke up with the coldest moment of the day, without the need for alarms.
The research showed that these individuals did not sleep for extended periods, over 12 hours, but rather emphasizing sleep quality. Consolidated, unfragmented sleep was more restorative and beneficial, even if it lasted fewer hours. Additionally, a cooler bedroom is recommended for better sleep, aligning with their natural sleeping patterns.
Impact of Modern Societies on Sleep
In contemporary societies, the constant exposure to artificial light, which can suppress the production of melatonin, disrupts natural circadian rhythms. The work schedules, such as those of firefighters, often involve frequent interruptions that lead to fragmented sleep. This can result in Leptin resistance, a protein responsible for satiety, leading to obesity. Moreover, irregular sleep schedules can affect hormone secretion, contributing to chronic diseases.
Lessons from History on Sleep
By examining historical sleep patterns and comparing them with modern practices, we can see that the key to better sleep lies in maintaining consistency and quality. Our prehistoric ancestors adapted to their environments, and their natural sleep rhythms were deeply connected to the changing of the seasons and the availability of light.
Note from the Author: For further insights, I refer to my article titled Can the Body Learn to Do With Less Sleep on HealthCentral. In this article, I discuss a study conducted on three tribes in Namibia, Tanzania, and Bolivia, which were not using modern technology including electricity and were primarily hunters. The study revealed that temperature played a key role in their sleep schedule, and they did not need 12 hours of sleep but rather sought quality over quantity.