16:23 19 October 2015
US researchers studied the sleeping patterns of traditional societies in Africa and South America, whose lifestyle closely resembles ancient hunter gatherers. The study, which including the monitoring of 98 people for 1,165 nights, revealed that they slept an average of 6.5 hours per night. This is 30 minutes less when compared to a study that said that the majority of people in the United States sleep for about seven hours.
Prof Jerome Siegel, from the University of California, Los Angeles, said: "The issue is: what is the data on how sleep has changed?
"And it occurred to me that these groups, which are rapidly disappearing, give the last opportunity to really know what human sleep was like before we all created our various civilisations.
"What is absolutely clear is that they don't sleep more than we do."
Surprisingly, natural light did not contribute greatly to the sleep pattern while temperature plays a crucial role. The study concludes that most people fell asleep on average of 3.3 hours after sunset.
"What we saw was quite striking - that sleep is occurring during this period of falling temperature and when the temperature hits bottom, they wake up," said Prof Siegel.
"This is quite surprising."
Prof Derk-Jan Dijk, from Surrey Sleep Research Centre, commented on the research and said: "There are people in our society who don't get enough sleep, there is no doubt about it,"
"The question of whether we sleep that much less than so many years ago has been unanswered in ways - we need to be careful in interpreting that data."
"We have artificial light in abundance and we have our clock-determined social commitments and the timing doesn't have anything to do with sunrise or sunset. We are to a large extent disconnected from those natural cycles.
"I think we need to re-evaluate the timing of our social schedules, including work, relative to the natural environment. Our social environment has an impact on when we decide to go to sleep and wake up.
"Also if we look at our environmental variables in the light-dark cycle in our homes and the temperature, I hope his paper will make us see how relevant are they for the timing of our behaviour."