Modern sleep research only really began in the middle of the 20th century, with the milestone discovery of REM sleep in the 1950s.
Before that, sleep was widely regarded as a ‘passive process’ and hence, not of great interest in terms of scientific inquiry.
When it comes to real ‘facts’ about sleep, this relative lack of empirical evidence, has, over the years led to a disproportionate amount of homespun advice, folk wisdom and old-wive’s tales.
There are many mysteries of sleep yet to be solved. The good news is, in the last few decades, science has been able to separate a lot of the fiction from fiction.
Over 11 days, we are exploring some of the scientific research behind 33 of the most commonly held myths and misconceptions about sleep.
19: Dreaming only happens during REM sleep
REM (rapid eye movement) is one of the five stages of sleep that occur every night. Discovered in 1953 by Kleitman and Aserinsky, it was observed that when patients were awoken during the REM phase the recalled their dreams most vividly.
From then on REM has always been associated with dreaming.
Although REM dreams tend to be longer, more complex and bizarre, according to a 2004 study, dreaming also occurs independently throughout non-REM sleep. Another condition in which dreaming occurs is known as the hypnagogic state.
This is the transition between wakefulness and sleep, and may involve imagery and sounds often likened to hallucinatory experiences.
20: Yawning is just a sign of tiredness
Yawning is typically thought of as an indicator of fatigue, but in reality the real causes of yawning remain a mystery even after continued scientific scrutiny.
One theory is that yawning facilitates low oxygen levels in the lungs, but this has largely been discredited after observations of foetal yawning (there’s no oxygen in the womb).
Another mystery of yawning is how contagious it can be. Studies have shown that yawning can trigger off a contagious response in up to 60% of people who are exposed. It even affects dogs!
Some scientists have proposed contagious yawning may have helped our ancestors to coordinate times of activity and rest. Another recent experiment has suggested that yawning may be an attempt to cool the brain down.
21: A warm glass of milk before bed
Some people believe that a glass of warm milk can help you fall asleep because it contains tryptophan, an essential amino acid which is responsible for producing serotonin, which is vital for healthy sleep.
However, evidence has shown that a glass of milk on it’s own will not produce these effects. You body also needs carbohydrate-rich foods which help to produce insulin.
This is essential in order for tryptophan to have any sleep inducing effects. It’s possible that the effects of milk as a sleep aid may be purely psychological. People may associated milk with their childhood, motherly care and being tucked up in bed and night.