Newsademic British English edition 260

leep
 
st u d y
Modern technology has changed 
the way we live our lives. Some be­
lieve that constant use of electronic 
devices, such as computers and 
smartphones, means people have 
far less sleep. However, a new study 
suggests that this may not be true. 
People with no electronic devices 
and no electricity seem to sleep for 
a similar length o f time.
Sleep is important for humans 
and many animals. It helps build and 
repair the body’s systems. Bones, 
muscles, nerves and the immune sys­
tem (which fights disease) all need 
sleep to work properly. Human sleep 
comes in two forms. One is called 
REM and the other non-REM.
REM stands for Rapid Eye 
Movement. During REM sleep a 
person’s eyes (under their closed 
eyelids) move randomly. Another 
characteristic o f REM is paralysis. 
This is when the body can’t move. 
REM sleep is when a person is most 
likely to have vivid dreams.
Non-REM sleep is different. If 
people sleepwalk or talk in their 
sleep, it usually happens during 
non-REM sleep. Dreaming may 
occur, but it is not as lifelike as 
REM dreams. About 80% o f hu­
man sleep is non-REM.

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29th October 2015 
N e w s a d e m ic .co m ™
 - British English edition 
page 
10
The National Sleep Founda­
tion is an organisation that of­
fers advice about sleep and sleep 
disorders. It says that humans 
should sleep for between seven 
and nine hours each night. Many 
people have less sleep than this. 
Researchers from the USA wanted 
to find out if people are now get­
ting less sleep because o f modern 
technology and electric lighting. 
To test this, they monitored the 
sleep patterns o f societies that 
have no electricity.
San people in Africa
The researchers selected three 
different societies for their study. 
The Hazda people live in Tanzania, 
in eastern Africa. The San people 
come from southern Africa. The 
third are known as the Tsimane. 
They live in Bolivia, in South Amer­
ica. All o f these people still have a 
‘hunter-gatherer’ lifestyle. They use 
fire for heat and light and have no 
electric power.
Hunter-gatherers hunt animals for 
food, They also collect fruit, nuts and 
edible plants. Nowadays, the Tsi­
mane also grow some crops. The re­
searchers asked 94 people from these 
societies to wear a wristwatch-like 
device for about 1,000 days. The de­
vices measured two things. One was 
the amount o f daylight and the other 
was how much the people moved.
The recordings showed that most 
o f the people who wore the devices 
fell asleep about three and a half 
hours after sunset. They got up
around one hour before dawn, or 
sunrise. In the winter months the 
San didn’t get up until one hour after 
sunrise. It used to be thought that 
people without electric lighting went 
to bed soon after the Sun went down. 
Yet these people do not do this.
The researchers think the San 
got up later because the mornings 
where they live are colder. They 
would go to sleep when the night 
started getting cold and wake up 
when it reached its lowest tempera­
ture. In the colder winter months, 
people would sleep slightly longer 
than in summer.
On average, the Hazda, the San 
and the Tsimane all slept for less 
than seven hours each night. This is 
similar to people living in the rest of 
the world. None o f these societies 
sleep, or nap, during the day. W hat’s 
more, they never have trouble sleep­
ing at night. N ot being able to sleep 
is known as insomnia. Nowadays, 
this is not an uncommon complaint. 
However, when asked about insom­
nia, the Hazda, the San and the Tsi­
mane did not understand the question. 
In their languages there is not a word 
for insomnia.
N ot everyone agrees with the re­
searcher’s conclusions. Many still 
believe that electricity and elec­
tronic devices have a bad effect on 
people’s sleep patterns. □
N