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| Ancestors 'had less sleep' than we do | Ancestors 'had less sleep' than we do |
| (about 2 hours later) | |
| Our ancestors may have got less sleep than we do, a study suggests. | Our ancestors may have got less sleep than we do, a study suggests. |
| US researchers studied the sleeping patterns of traditional societies in Africa and South America, whose lifestyles closely resemble ancient hunter gatherers. | US researchers studied the sleeping patterns of traditional societies in Africa and South America, whose lifestyles closely resemble ancient hunter gatherers. |
| They monitored 98 people for 1,165 nights, and found that they slept for an average of 6.5 hours per night. | They monitored 98 people for 1,165 nights, and found that they slept for an average of 6.5 hours per night. |
| By comparison, the scientists said that most people in the US get about seven hours, according to a large sleep poll. | By comparison, the scientists said that most people in the US get about seven hours, according to a large sleep poll. |
| The new study, published in the journal Current Biology, also finds that temperature played a greater role than light in shaping sleeping patterns. | The new study, published in the journal Current Biology, also finds that temperature played a greater role than light in shaping sleeping patterns. |
| Prof Jerome Siegel, from the University of California, Los Angeles, said: "The issue is: what is the data on how sleep has changed? | 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. | "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." | "What is absolutely clear is that they don't sleep more than we do." |
| No naps | No naps |
| From artificial lights, to late night TV, and now the ever-present glow of our smart phones, modern life is often blamed for ruining our sleep. | From artificial lights, to late night TV, and now the ever-present glow of our smart phones, modern life is often blamed for ruining our sleep. |
| To put this to the test, the researchers studied the Hadza of Tanzania, the San of Namibia and the Tsimane of Bolivia, fitting their volunteers with wristwatches that monitor sleep. | To put this to the test, the researchers studied the Hadza of Tanzania, the San of Namibia and the Tsimane of Bolivia, fitting their volunteers with wristwatches that monitor sleep. |
| "All three groups have pretty much the same sleep duration and pretty much the same timing of sleep," said Prof Siegel. | "All three groups have pretty much the same sleep duration and pretty much the same timing of sleep," said Prof Siegel. |
| "This gives me reasonable confidence that they reflect the common human biology and they are not a function of their particular situations, which are different." | "This gives me reasonable confidence that they reflect the common human biology and they are not a function of their particular situations, which are different." |
| As well as discovering that the average sleep duration was six hours and 25 minutes, the researchers also found the participants very rarely took naps. | As well as discovering that the average sleep duration was six hours and 25 minutes, the researchers also found the participants very rarely took naps. |
| While some European documents suggested that people used to wake up for a while during the night, sleeping in two shifts, the researchers found this was not the case with the hunter gatherers. | While some European documents suggested that people used to wake up for a while during the night, sleeping in two shifts, the researchers found this was not the case with the hunter gatherers. |
| Surprisingly, natural light did not have as big an influence as was thought. | Surprisingly, natural light did not have as big an influence as was thought. |
| Most people fell asleep on average 3.3 hours after sunset. | Most people fell asleep on average 3.3 hours after sunset. |
| However, temperature was an important factor. | However, temperature was an important factor. |
| "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. | "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." | "This is quite surprising." |
| And despite the fact that these traditional societies slept less than the National Sleep Foundation's recommended seven to nine hours a night, the researchers said they did not grumble about being tired. | And despite the fact that these traditional societies slept less than the National Sleep Foundation's recommended seven to nine hours a night, the researchers said they did not grumble about being tired. |
| Insomnia was also extremely rare - and two of the groups did not even have a word for it. | Insomnia was also extremely rare - and two of the groups did not even have a word for it. |
| What's stopping my slumber? | |
| Which five things ruin a good night's sleep? | |
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