Henry Nicholls - Sleepyhead: The Neuroscience of a Good Nights Rest

Sleep, those little slices of death; Oh how I loathe them.

Edgar Allan Poe

How is your necrophilia?

My friend was asking after my narcolepsy, a seriously disabling neurological condition that I have lived with now for more than half my life.

Its still an issue, I replied. Thanks for asking.

to sleep with lots, whilst narcolepsy involves lots of sleep.

The onset of most sleep disorders is usually slow, so slow it can be difficult to notice what is happening. I was 21 and halfway through my second year at university when I experienced my first symptoms. I had always been an early riser. I loved mornings, eager for the day ahead. But gradually, over the space of several months, something began to change. Within an hour of waking, it felt as if a smog were seeping into my brain and anaesthetising my faculties until I was left with no option but sleep. If circumstances allowed, I would give in and go back to bed, but I soon found that more sleep did nothing to refresh me. I tried to fight it instead, for a whilegoing to lectures, tutorials, running the college barbut the constant struggle to prevent myself from drowning was almost worse.

I came up with little tricks that would hold off sleep for a minute or two, pinching myself, running violently on the spot, shouting at the top of my voice. Just writing about this makes me feel a little nauseous, even now. The feeling would begin to creep up on me all over again. I could battle like this for tens of minutes, convinced I was managing to take in a book, watch a film or even chat with friends, only to find I had no recollection of what had just happened. Had I been asleep, or hadnt I? The alternatives seemed to be stark: either spend all day in this zombie-state, or simply stay in bed. I began to confront the fact that I couldnt function in a meaningful way. I struggled through my degree, dribbling over lecture notes, dozing through tutorials, overdosing on caffeine to extend the fitful snatches of wakefulness I needed to make the grade.

In some lectures, I was just one of some 500 students. With tiers of desks stretching up and far away from the lecturer, I could sit near the back and put my head down without fear of being spotted. In a tutorial, however, with one professor and two students, things were not so easy. Very quickly, often within minutes, the small, sometimes windowless room and hulking radiators would conspire to bring on an attack of sleep. In order to keep up appearances, I had to keep my eyelids open. With considerable effort I found I could do this but I know (because Ive seen it in other people with narcolepsy) that there would have been no spark, no life, in my eyes.

Sleep v.

To take repose by the natural suspension of consciousness

It is perhaps understandable that sleep, as defined here by the Oxford English Dictionary and as most of us understand it, is a fairly vague concept. Understandable because it is so extraordinarily variable, differing wildly from one conscious species to the next.

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In between these extremes, there is a remarkable diversity of sleep. Most mammals are polyphasic in their sleep, drifting off repeatedly over the course of 24 hours. Dogs are the perfect exponents of this approach. Some species are biphasic, with two discrete sleeps a day. Rabbits, for instance, are most active at dawn and dusk, a crepuscular existence that carves out two clear periods for rest, one in darkness and one in daylight. Marine mammals, like dolphins and whales, boast the remarkable ability to sleep with one half of the brain at a time. Then there is also a handful of species with monophasic sleep, dividing up each day into one clear period of wakefulness and one period of sleep. Some of these are nocturnal in their habits, like owls, some are diurnal, like people.