Blame easy access to electricity for less sleep: Researchers observe that in response to artificial light, people tend to sleep later in night and for fewer hours as opposed to those without electricity.

Poor sleep is becoming a major problem in today’s world. People say the culprits are smartphones, continuous connectivity thanks to Wi-Fi or even media and the need to be in the know; the bottom line remains that sleeping habits have definitely become worse. And according to researchers at University of Washington, the real blame lies with artificial light.

Researchers when comparing modern lifestyles with the traditional settings of a hunter-gatherer society found that less sleep was due to exposure to artificial light and access to electricity. The more removed a community was from electricity, the more hours they slept at night.

For the study, two indigenous communities situated in northeastern Argentina were chosen. The distance between the two was around 31 miles. The communities were identical in ethnic and social as well cultural backgrounds, the only difference was that one had no electricity only natural light whereas the other had access to 24 hours of electricity.

The researchers paid a visit to each community for the duration of a week in both summer and winter. To monitor activity, they used electronic devices in the form of bracelets and worn as watches, which were used to track changes in movement. A stationary wrist for large amounts of time indicated that the person was asleep.

It was found that while both communities slept fewer hours in the summer months and longer hours in the winter months, but the community with electricity tended to sleep an hour less than those without electricity.

To corroborate the data from the wristbands, participants were also encouraged to keep “sleep diaries”. They logged in times they went to sleep, woke up and also the times and durations of naps taken during the day.

It was found that due to access to electricity, the people just opted to turn on the lights and delayed going to bed until later at night.

Previous research has shown that our body’s internal clocks or the circadian rhythm can be disrupted by artificial light. This alters the sleep-wake cycle as well.

This occurs because our circadian rhythms are set by our exposure to light. If we were to spend 2 weeks in a dark cave with no light, after 4 days, our circadian rhythms would be out of tune. So light tells our body’s that it time to get up and work while night tells us it’s time for sleep and rest.

The findings in the study indicated that human beings are biologically driven to sleep more in the dark winter months. In Argentina, the difference in daylight hours in summer and winter are at most 2.5 hours but the participants still tended to sleep for longer in winter months. In Seattle, the difference could be as much as 8 hours of daylight hours.

Lead author Horacio de la Iglesia, who is a University of Washington Biology professor explained, “This study presents a proxy of what happened to humanity as we moved from hunting and gathering to agriculture and eventually to our industrialized society.”

The research was published online in the Journal of Biological Rhythms. It was funded by the National Science Foundation, the Leakey Foundation and the NIH. The community with access to electricity slept less than the community without access.