A lot more goes on after bedtime than we know about, writes Gill Moodie
The next time you are tossing and turning in bed, it might ease the night to think of scientists at the University of the Witwatersrand who are holding vigil over electro-encephalogram (EEG) machines to try to understand that mysterious activity that consumes about 20 years of a human’s life: sleep.
To young scientists such as Fiona Baker, a physiology graduate who is doing her PhD on sleep, it is a fascinating field in which to choose a research project that has not been covered before. “There are thousands of things we don’t know about sleep,” says Baker, who is researching the sleeping patterns of young women, especially the effect of the menstrual cycle.
It has been established that there are variations in the time spent dreaming during the menstrual cycle and of brain activity during non-dreaming sleep.
Baker is trying to find out why this is and why women with premenstrual syndrome can experience insomnia or unpleasant dreams, or wake up during the night. The indications are that changes in hormone levels and body temperature during the cycle all affect sleep.
The relationship between the female reproductive system and sleep is still a puzzle. Studies in the United States show that 75% of women experience insomnia and disrupted sleep before the onset of menopause, but the cause is yet to be established.
After 60 years of serious study, scientists cannot even agree on the purpose of normal sleep. That it is a restorative process for the body is born out by processes such as increased protein synthesis and cell division during sleep.
But the big picture is more complex: data that shows foetuses and babies exhibit REM – rapid eye movement that occurs during dreaming – points to a connection between dreaming and brain development.
Sleep-deprivation experiments throw up other clues. Lack of sleep diminishes reaction time, memory, language abilities and even warps reality in test subjects.
In 1959, Peter Tripp, a New York disk jockey, stayed awake for 201 hours while monitored by psychologists. After only four days he had trouble saying the alphabet. Paranoia and hallucinations followed, leading Tripp to believe there were spiders spinning webs on his shoes.
In South Africa sleep is a neglected field of study. The Wits sleep laboratory is the only one of its kind in the country. Established in 1985 as part of the medical school, the facility has three bedrooms into which they entice medical students to be their sleeping subjects. The bedrooms look like hotel apartments. “We try to make the students as comfortable as possible,” says Baker. Even the electrodes attached to their heads which convey brain waves to the computerised EEG feel like plasters and do not disrupt sleep.
In the morning, the researchers make breakfast for the subjects before attacking the lengthy analysis of brain waves, body temperature and blood samples. “Sleep is under-appreciated in South Africa,” Baker says with a chuckle. “In America sleep disorders are the thing to have.”
While studies show that 36% of Americans suffer from insomnia, there are no figures for South Africa. The Wits laboratory hopes to take part in a forthcoming World Health Organisation (WHO) study which may illuminate how South Africans compare to other nations in the sleep stakes. A WHO study released in 1996 of 26 000 subjects in 15 countries showed that sleep problems vary between nations: at the bottom of the scale was Japan with only 7%of subjects suffering from sleep problems, compared to 40% in Brazil.
It is possible that the proportion of South Africans suffering from sleep disorders is high as disrupting factors such as post- traumatic stress following violent crime incidents might play a part.
The Wits laboratory is already conducting research into fatigue in truck drivers who, Baker says, often do not stop for shut-eye at truck stops because of fears of crime.
Baker points out that sleep is as necessary to life as eating and drinking. Laboratory tests on rats deprived of sleep show that after the first week, the animal’s metabolic rate increases even as its body temperature mysteriously drops – a higher metabolic rates usually equals an increase in temperature. The animal dies after 21 days -about three days longer than it will last without food or water.
While the classic scientific route of investigation is to study other mammals to gain understanding of human behaviour, it tends to underline the complexities of sleep.
Some mammals, such as dolphins, use their brains in a different way to humans during sleep. They sleep with only half a brain – either the left or right brain. One half stays alert and sends messages to the dolphin’s body to rise to the surface for air. Like humans, all mammals dream or show signs of REM sleep. But there is one confounding exception: the spiny anteater.
The fact that animals sleep at all does not make good evolutionary sense as it forces them into a vulnerable state. The scenario that less sleep is the next evolutionary step for humans is reasonable as it would free up more productive hours.
Tests reveal that a sleeping person saves only 15% to 20% more energy than someone lurking on a couch. Is it worth being out of action for a kilojoule saving equivalent to a slice of bread?
However, as all of us who wake from a good night’s sleep know, it is invigorating and, say scientists, not unproductive: in fact, more than we know goes on after bedtime.