Deuda de Sueño: muestran que la raíz del problema está en la luz eléctrica

Sleep Debt

It's discovered that the root of the problem is in the electricity

Nobody doubts that Thomas Alva Edison, the wizard of Menlo Park, was a brilliant inventor. But apparently since Edison "lit the lamp" humans have begun to accumulate a sleep debt that we now know has multiple impacts on our health.

This is what a study just published by the Journal of Biological Rhythms indicates, by researchers from the universities of Washington, Yale, Quilmes and Harvard, most of whom are Argentines.

The study, which involved the collaboration of two hunter-gatherer communities from the province of Formosa, offers the first evidence obtained in a natural environment that the root of our chronic lack of sleep is the invention of Edison's, artificial light.

"We found what other studies done in the laboratory already recognized, where we manipulated aspects of exposure to light. But this is the first time we saw that this was fulfilled in nature," says the Argentine Chrono biologist Horacio de la Iglesia from Seattle, in the United States, where he's been teaching at the University of Washington for 12 years.

Diego Golombek, CONICET researcher at the University of Quilmes and co-author of the work, adds: "While there is some background work studying how lighting conditions change modify sleep in the lab, it is clear that sleeping in this environment cannot be considered a normal situation. In this study we determined the sleep cycle in natural conditions, in populations that are or are not exposed to electricity. [This is] an accurate measurement of the natural rhythm of the inhabitants of these populations, which makes the study even more relevant."

An Uncommon Stage

Deuda de Sueño: muestran que la raíz del problema está en la luz eléctrica

In reaching this conclusion, the scientists compared two indigenous communities, the Tobas/Qom with virtually identical ethnicities and lifestyles, but who differ in one aspect: access to electricity. One has electricity 24 hours per day; the other depends on natural cycles of light and darkness.

This uncommon scenario in the northwest, where the two communities live about 50 km away, where a couple of Argentine anthropologists who do research at the University of Yale, Claudia Valeggia and Eduardo Fernandez-Duque have worked for over a decade.

There, they could see that the community that had electricity in winter, sleeps about one hour less than the community that did not, and in the summer, 45 minutes less. The two groups slept more in the winter than in the summer, suggesting that a biological clock in humans requires more sleep on dark and cold days than on long and warm days, the researchers say.

"The idea of this experiment came about 20 years ago at a biological rhythms conference where Diego and I were attending in the United States says De la Iglesia. There, a psychiatrist who worked a long time with the effects of light in humans, but in laboratory conditions showed that depending on whether you put your research subjects in a photoperiod simulating winter or summer, sleep patterns were modified. At that time, I told Diego. "We should look at the Argentine communities who don't have access to electricity to replicate this test under natural conditions'."

Golombek then did some studies, but at that time there was no technology to measure activity with the necessary precision and define sleep patterns quantitatively, the actimetry, which records periods of activity and rest.

Valmeggia and Fernandez also were partners with Golombek and De la Iglesia, and knew about these communities living on the outskirts of Engineer Juarez. "That led me to travel in 2012”, De la Iglesia says. The Tobas/Qom agreed and everything we did was minimally invasive. The actimeter is like a normal clock."

In total, 40 people were studied in several campaigns, men and women from 12 years old and up. "Since they were followed for several days, the data is highly significant," the scientist says.

"Years ago recalls Golombek- , our lab conducted a similar study in a Mapuche population without electricity through the analysis of daily sleep in school children, and although it was not as complete as in this case, and although we took data from the actimetry, we found the same seasonal variation between summer and winter. This was expected in a Patagonian population, but even more interesting is the finding of these changes in a subtropical climate such as Formosa, where annual changes are not as noticeable. Beyond that, the main finding is something that may sound logical or have common sense: electricity induces a decrease in the hours of sleep, particularly because people are going to bed later. Well, science sometimes has to put numbers to common sense and show it in a rational manner. Edison has been, among other things, a great thief of sleep."

Final Demonstration

As well as adding hours of daylight, electricity makes it possible to use iPads, monitors, TVs and other powerful stimuli, scientists believe that the study represents an underestimation of the lack of sleep we suffer and that in large cities it would be greater.

An important detail is that not all kinds of light work the same way. White light acts as artificial sunlight to synchronize the biological clock. But the most efficient way to delay and inhibit our internal clocks is blue light that largely integrates our artificial light and are emitted from the screens of our electronic devices.

"One of the measures to counter these effects is to try to get lights with a longer wavelength and try to get as little exposure as possible during the afternoon and evening to blue light or very intense light –De la Iglesia suggests. There are apps that remove the blue after a certain hour."

For Dr. Daniel Cardinali, director of Teaching and Research at the Faculty of Medicine at the Catholic University in Argentina and author of “What is sleep?” (Polity Press, 2014), who did not participate in the research, "this type of work with objective measurements is very interesting, because there is some disparity between what the polls show and what the actimetry is indicating in large numbers of people. These results are suggesting that the presence of light was a key to reducing and compacting the dream factor. It seems fantastic to analyze it in a natural environment, he adds. In addition Golombek and De la Iglesia are two top of the line Chrono biologists."

According to the scientists, a side benefit of the study is that, as the Toba/Qom are still in some degree hunter-gatherers, to register their patterns of sleep-wakefulness was like seeing the transition experienced by humanity from ancestral modes to urban life, live and direct, a process in which sleep was progressively reduced.

Golombek says: "The final demonstration of the effect of electric light in sleep was to come from a detailed comparative study of similar populations from a cultural and genetic point of view, as has occurred in this work. It was not enough to just measure our own sleep, with or without light, as there are too many variables that may confound the results Our study adds very conclusive evidence of something that we have been insisting upon in the field of chronobiology: that contemporary life is depriving us of valuable sleep and the consequences are not just being tired, but can have multiple impacts on performance, mood and overall health."

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