Sleep experts are quick to blame bright street lights, TVs and the ever-distracting smartphone as the reasons why nearly one-third of U.S. adults dont clock enough sleep on a regular basis. (For good reason some types of light can seriously mess with the bodys ability to wind down before sleep .)

But a new study published in the journal Human Biology this month suggests that even without distractions from artificial light sources and other modern technology, human sleep patterns can still be far from ideal.

A group of researchers, most of them from Duke University, tracked the sleep patterns of people living in a Madagascar farming village without electricity and few other sources of artificial light. The data showed the villagers slept less than a similarly sized group of people of the same ages in the U.S. and another similar group in Italy. And their sleep quality was actually worse.

But theres a catch: The people in the rural community had stronger, more consistent circadian rhythms, which other research has linked to better health overall .

This is proof in concept that, in traditional human populations with greater exposure to their environment, you can have a strong circadian rhythm and poor, short sleep at the same time, study co-author David Samson, a senior research scientist in evolutionary anthropology at Duke University, told The Huffington Post.

Thats a significant finding, considering having a more consistent circadian rhythm (one that isnt disrupted by things like irregular shift work and jet lag) has been linked to lower risks of developing memory problems, heart and metabolic diseases and some cancers .

Smartphones arent the only reason our sleep gets interrupted.

For the study, the researchers tracked the sleep of 21 adults in the rural farming village of Mandena in northeastern Madagascar for 292 nights total. Though some people in Mandena have generators or solar panels, the village itself has no infrastructure for electricity, which means that most people rely on cooking fires, kerosene lamps, a few battery-powered flashlights or the moon and stars for light after the sun goes down.