Before artificial light was invented, the moonlight was the only major source of light for nighttime. However, it was still debated until recently whether sleep timing is affected by lunar phases. What do the new studies have to say about this?
According to a study done by the University of Washington, there is a clear synchronization of our sleep timings with the cycle of the moon. It observed people living in different kinds of environments – from a rural area without access to electricity to a highly urbanized setting in the US. The results that were published in the Science Advances journal show that sleep definitely starts later on the nights before a full moon and is shorter.
There is a clear lunar modulation of the sleep patterns of humans. Although the effect is more obvious in communities that don’t have access to electricity, it is distinctly observable in communities with electricity as well.
Scientists used wrist monitors to track sleep patterns among 98 participants. They were living in three different Toba/Qom indigenous communities located in the Argentine province of Formosa. These communities had different levels of access to electricity: one had no electricity access, the second one had limited access, while the third community was a part of a highly urban setting, and therefore had full access to electricity.
The scientists collected sleep data for one-two lunar cycles for about three-quarters of the Toba/Qom members. Those in the urban setting slept less and went to bed later than rural participants who had limited or zero access to electricity. However, all the study participants showed the same sleep oscillations – which was related to the moon’s 29.5-day cycle.
The bedtimes differed by around 30 minutes and the total amount of sleep time differed by 46 to 58 minutes. After discovering this pattern, the scientists analysed the data from sleep-monitors of 464 college students from the Seattle-area. It confirmed their study data - they had the same sleep oscillations.
The research team also found a semilunar oscillation of sleep patterns in all the three Toba/Qom communities. However, this effect is smaller and mostly noticeable in the rural communities, so it needs further research.
The research findings prove that no matter how advanced humankind has become in the recent ages, there is still an evolutionary connection we have to nature. It not only defines our sleep patterns but may have effects on other aspects of our life as well.
