Chances are that, as a uni student, you’re well acquainted with the “all-nighter” – that phenomenon that occurs when you’ve got an assignment that’s due in less time than it is likely to take you to finish it.
If you’re one of those super-smart and super-organised people who always completes work well before it’s due (you have the right to be smug, but you should know that you’re envied and despised in equal measure), you may not have experienced the effects of sleep deprivation. But the rest of us will be well familiar with the zombifying effects of forgoing sleep.
Miss out on just one night’s sleep and your body and brain knows it. You feel tired, your muscles ache, your brain doesn’t work as quickly as usual, and you might even experience visual hallucinations. A friend of mine in high-school claimed to see pink flashes from the corner of his eyes and occasional glimpses of Christina Aguillera after an all-night party followed by an 18 hour stretch working at the supermarket.
Recent research conducted in New Zealand and Australia and reported world-wide found that people who drove after staying awake for 17 to 19 hours performed worse than people with a blood alcohol volume of the legal limit of most Western European countries. This was explained by the fact that sleep deprivation can impair motor skills, affect coordination, reaction time, and judgement.
Consistently not getting enough sleep over a prolonged period can have serious health effects. It is linked to weight gain, high blood pressure, diabetes, and an increased risk of developing calcium deposits in the arteries – a precursor to heart disease.
Edgar Allan Poe (or Henry Wadsworth Longfellow – the internet can’t decide) said that he loathed sleep: “those little slices of death”. But go without it for a while, and the desire for sleep becomes overwhelming.
Sleep deprivation has been used as a form of torture, and in experiments using rats, has been found to lead ultimately to death. The former Israeli Prime Minister Menachem Begin said of being subjected to sleep deprivation by the KGB: “In the head of the interrogated prisoner, a haze begins to form. His spirit is wearied to death, his legs are unsteady, and he has one sole desire: to sleep…Anyone who has experienced this desire knows that not even hunger and thirst are comparable with it.”
Sleep is regulated by the suprachiasmatic nuclei, a pair of structures in the brain’s hypothalamus. The suprachiasmatic nuclei receive and interpret information from photosensitive ganglion cells in the retina, and pass information on to the pineal gland, which secretes melatonin. Melatonin is a hormone with a number of functions including the regulation of the sleep-wake cycle.
Sleep is divided into two main types: rapid eye movement (REM) sleep, and non-REM sleep. Sleep usually progresses through a number of phases, characterised by differences in brain-waves. REM sleep is usually the final phase of sleep, taking up about a quarter of all time spent asleep. Most memorable dreaming occurs during REM sleep.
Despite sleep being such an important part of our lives, it is still poorly understood, especially in terms of the function(s) of sleep.
Sleep may have a healing and restorative function. In studies of sleep deprivation, wound healing and the immune system have been negatively affected. A number of hormones, including growth hormones, are preferentially secreted during sleep. Sleep seems to play an important role in development, which can be severely disrupted in human infants and children who are deprived of sleep for extended or ongoing periods. Sleep may be important in energy conservation – when rats are deprived of sleep, their energy consumption and expenditure increases.
Studies into the role of sleep in memory processing have found that working (or ‘short-term’) memory is severely affected by lack of sleep, while studies in which participants were divided into groups whose sleep was disrupted at different times during the night suggest that procedural memory (‘how to’ memory and knowledge) benefits from late, REM, sleep, while declarative memory (memory for facts) benefits from early sleep.
Well, I don’t know about you, but all this reading about sleep has inspired me to take a nap. Why not have a little nap yourself? And if someone asks you why you’re sleeping during a lecture, let them know that you’re just doing everything you can to be the best student that you can be.