The Healing Power of Sleep
(June 7th, 2013) A lack of sleep leaves us feeling groggy, slow and possibly even irritable. But why? What is the function of sleep? Two researchers from the UK have suggested a new hypothesis.
Many mysteries revolve around the little brother of death – sleep. Why is it that we humans have to take some time off every day? To save energy? To process the day’s events? Or is sleep maybe the “greatest mistake evolution ever made” as sleep researcher Allan Rechtschaffen said. The answer is we don’t know. “The only reason we need to sleep that is really, really solid is because we get sleepy,” Stanford University’s William Dement, co-discoverer of REM sleep, told National Geographic in 2010.
Hypotheses are proposed and rejected constantly. Last month, Vladyslav Vyazovskiy from the University of Surrey, UK and Kenneth Harris, from University College London, UK, published a paper in Nature Reviews Neuroscience, in which they review the current research and hypotheses proposed over several decades about the function and necessity of sleep. Based on that knowledge, they propose their own sleep theory.
Vladyslav tells me “the question of ‘why do we sleep?’ is among the top ten unsolved mysteries of the brain, according to Discovery Magazine”. Unlike the majority of researchers in the sleep field who take the traditional ‘clinical’ approach, Vladyslav takes a more ‘basic’ approach. His studies, he tells me, typically involve the use of laboratory mice that are “habituated to the research environment and trained to do specific tasks”, before “implanting tiny electrodes in their brains to record activity of individual neurons during the tasks, spontaneous undisturbed waking and during sleep”.
Vladyslav and Harris now propose that sleep – “a state of globally synchronized neuronal activity, reduced sensory input and behavioural immobility” – allows for “maintenance of individual neurons” involving “repair of minor (but not major) cellular damage before it becomes irreversible”. They go on to say that sleep deprivation is associated with “reduced cognitive function”, such as the inability to effectively perform simple tasks because neurons “reduce synaptic activity”, which “ensures that the neuron is never permanently damaged”.
Many people suffer from sleep disorders and Vladyslav believes that “understanding the basic physiology of sleep is essential for developing proper therapeutic strategies to improve our sleep”. This is something that most of us would be grateful for at least at some point during our lives. Furthermore, in the paper the authors state that it has also been suggested that sleep deprivation may lead to an increased probability of developing neurodegenerative disorders, such as Alzheimer ’s disease, which further emphasises the need for further research in this field.