Does Frequent Sleep Problems Investigate a Natural Survival Drive?

Maybe sleep problems are just part of the evolutionary past
At the present time, many people suffer from sleep problems. Often, bad sleep is considered a consequence of hectic modern life. Current research suggests, however, that a particularly light sleep or repeated waking up during the night are a survival mechanism that is supposed to protect against nocturnal threats.

Researchers at Duke University, North Carolina and the University of Nevada, Las Vegas, found that nocturnal sleep difficulties are a survival mechanism that protects people from possible night-time threats, according to the press release on the findings of the current study.

Many older people suffer from sleep problems. Often, they wake up very early in the morning and can not fall asleep. Researchers found that these could be consequences of our evolutionary past. (Image: Edler von Rabenstein - fotolia)

Researchers study sleep patterns of a native tribe in Tanzania
In their current study, the researchers studied the sleep patterns of the people of a so-called hunter-gatherer tribe in northern Tanzania. The experts found that frequent waking at night and different sleeping plans between old and young people ensure that in most cases at least one member of the tribe is always awake.

Bedtime of the tribe members very low
Over a period of three weeks, there were a total of only 18 minutes in which all 33 tribal members slept at the same time, the authors explain. In our observation of the population, we noticed that the total sleeping time of the tribe members is quite low. In our Western society, we live much safer, so we actually sleep better, explains author David Samson from Duke University.

Affected suffer less often from sleep problems
Although the people of the tribe generally sleep less, the sufferers suffered less often from sleep problems and insomnia, which are widespread, especially in older people from the modern industrialized nations, say the scientists.

Experts studied Hadza tribe in northern Tanzania
The study focused on the so-called Hadza in northern Tanzania, which live in groups of twenty to thirty people. During the day, men and women go their separate ways to collect tubers, berries and honey and to hunt animals, the experts explain. In the evening all the tribe members meet again. The Hadza often sleep together in their huts made of grass and branches.

Study provides insight into human evolution
The Hadza show us an important part of human evolutionary history. They live in a style that is most similar to our past, explains author Alyssa Crittenden of the University of Nevada. For example, they sleep on the floor and have no synthetic lighting or regulated indoor climate.

Physicians study the sleep habits of 33 participants
The researchers followed the sleep patterns of 33 healthy Hadza men and women. These wore watch-like devices on their wrists for a period of twenty days. So the movements should be recorded during the night. Typically, participants woke up several times a night to turn, smoke, or care for crying babies, say the scientists.

Variation and flexibility in human sleep is normal
When people are in a lighter sleep stage, they are more attentive to any kind of threat in the environment, explains author Charlie Nunn of Duke University. On average, more than a third of the group had been awake at all times or only slightly asleep. The results show that variation and flexibility in human sleep are completely normal, adds author Samson.

What sleep habits did the participants have??
Previous studies have already found similar patterns in birds, mice and other animals. In humans, however, the phenomenon has now been observed for the first time, say the doctors. On average, participants went to bed shortly after 10pm and woke up at 7am. However, there were some people who slept at 8pm and woke up at 6am. These were mostly older participants. By contrast, younger participants usually slept from 11 pm to 8 am, the experts add.

The sleep problems of older people are often not real disorders?
The authors claim that the different orientations of the sleeping habits of adolescents and older people could be an evolutionary adaptation that kept our ancestors safe when sleeping in mixed age groups. Many elderly people go to doctors today and complain that they wake up early and can not fall asleep again, says Nunn. Often, however, there are probably no health problems at all, and perhaps some of the so-called sleep disorders are just a relic of the evolutionary past, which was initially beneficial to humans, the researchers explain. (As)