A major complaint of our times is that the modern lifestyle – with its artificial lighting, electronic devices and supply of caffeine – has shortened sleep duration from ”natural” levels and disrupted its timing. But people who live away from the trappings of city life may sleep even less than us, according to research published in the journal Current Biology.

Share on Pinterest Sleeping only 6.5 hours a night may not be a sign that we need sleeping pills.

The supposed reduction in sleep duration has been linked to obesity, mood disorders and a number of other physical and mental illnesses thought to have increased recently; although complaints about sleep disorders have been documented since the 1880s.

New evidence now shows that three ancient groups of hunter-gatherers – living a traditional way of life in different parts of the world, without electricity, distractions and heating or cooling systems – sleep a little under 6.5 hours a night on average.

They do not take regular naps, nor do they go to sleep when darkness falls. In other words, their sleep habits are not significantly different from those in the industrialized world, although they usually do wake up before the sun rises.

In these societies, individuals are exposed from birth to natural sunlight, and a continuous seasonal and daily variation in temperature.

To investigate how people slept before the modern era, Jerome Siegel, of the University of California-Los Angeles, and his colleagues investigated three traditional human hunter-gatherer societies: the Hadza of Tanzania, the San of Namibia and the Tsimane of Bolivia.

The researchers recorded the sleeping habits of 94 individuals around the clock to collect data representing 1,165 days in all.