Science knows that nowadays people tend to sleep less than they used to before modern times. We tend to blame modern lifestyle and technology for that. In other words, we stay longer at night browsing the internet and alarm clocks wake us up early to go to work or class. But now scientists from University of Washington have conducted the study that links artificial light to our contemporary sleep deprivation.
The researchers compared traditional hunter-gatherer living conditions to a more modern setting. Results of this research for the first time suggest that access to artificial light and electricity has shortened the amount of sleep humans get each night. Lead author Horacio de la Iglesia, said “Everything we found feeds what we had predicted from laboratory or intervention studies, where researchers manipulate certain aspects of light exposure. But this is the first time we’ve seen this hold true in a natural setting”.
To get objective and informative results, researchers had to compare similar groups. That is why they compared two traditionally hunter-gatherer communities that have almost identical ethnic and sociocultural backgrounds, but differ in one key aspect – access to electricity. They wanted to see if such simple factor of electricity and artificial light could lead to a smaller amount of sleep during an average week in both the summer and winter.
Scientists found these two groups in Argentina. One has a 24hour access to free electricity and can turn on the light at any desired time, while another relies only on natural sunlight. The community that had access to electricity slept about an hour less than their counterparts with no electricity. Researchers found that it was due to people who had the option to turn on lights and go to bed later. Both groups slept longer in the winter, despite the fact that summer and winter daylight hours differ about two and a half hours at most in that region.
The study was conducted in 2012-2013, but it can be considered to be an accurate representation of our ancestors and how their lifestyle and sleep patterns changed when electricity became available. However, because both of these groups, despite one having electricity, still live in very primitive conditions. This must mean that with our access to electricity and technology the impact on our sleep habits is even greater.
Scientists, of course, could not watch people sleep and observe their sleeping habits directly. So they used technology. They visited each community for a week during the summer and winter, placing bracelets onto the wrist of each study participant to monitor activity. These bracelets can track slight changes in movement – if a person is not moving for a longer time, it means he is sleeping. Participants also kept their own sleep diaries, where they wrote times they went to bed and woke up, as well as any naps throughout the day. This was done to check the information of the bracelets.
Scientists also noticed that even though we think we isolated ourselves for seasonal effects, they are still embedded into our nature, which explains why humans tend to sleep longer in winter. However, artificial light does not just push sleep-wake cycles back, it can also disrupt our circadian clock. Now scientists are thinking about ways to expand the research to get more information about links between electricity and sleep patterns in such communities.
The researchers are planning to look next at whether the later sleep onset and reduced sleep in the community with electricity is due to a shift in the biological clock by measuring melatonin levels in the two communities. They will also study the effects the moon cycle may have on sleep patterns as well. These are very interesting researches, as they may provide better understanding of how modern technology and artificial light affects our sleep habits.