The surprising truth about a bad night's sleep

by Jenny Nicholls / 16 May, 2019
RelatedArticlesModule - sleep

“Two of his friends were sleeping on the floor and (while asleep and dreaming) he believed that the rotary blades of a helicopter were breaking off while they were spinning, and flying at him, so he was dodging and diving. And as the final one came at him, he swan-dived into what he thought was grass but was actually his two friends on their mattress. They were woken up at 4am by quite a large Alex landing on them saying, ‘Oh God, did you see that helicopter?’”

Alex, a London charity worker, is an amiable young man in his 20s. He has “sleepwalked” since childhood – although the word seems wholly inadequate to describe the baroque variety of his late-night antics. Some are funny but innocuous, like the time his flatmate woke to find Alex sitting at the end of his bed using a shoe as a telephone to order a pizza. And there was the night he stood on his desk, shouting that tiny gazelles were eating his feet.

But sometimes Alex’s “sleepwalking” is more worrying. He has climbed, naked, imperious and unwakeable, into a friend’s bed at night. He has broken into a neighbour’s house in his underwear, and scaled high window ledges. And there was the time he broke a finger crashing into a cupboard he thought was a drowning girl.

Alex is fortunate enough to be a patient of Dr Guy Leschziner, a compassionate English neurologist and sleep physician whose book The Nocturnal Brain (Simon & Schuster, $38) uses case histories such as his to cast light on the twilight world of sleepwalking, insomnia, narcolepsy, night terrors and other sleeping disorders. What causes them? And what do they tell us about the human brain?

Alex is an otherwise sane young man, and his experiences are the stuff of bar-room legend for his friends. They also tell us something interesting about what the brain does – or is supposed to do – when it sleeps. The part of Alex’s brain that regulates movement and emotions can be awake, while the parts that regulate memory, consciousness and rational thought are asleep. Without these, he believes his irrational dreams – like the tiny, toe-nibbling gazelles. And without the normal paralysis of his muscles in sleep, he acts them out physically.

“We used to think of sleep as being an ‘on’ or ‘off’ brain state: either you are awake or you are asleep; there is nothing in between,” Leschziner says. “But in recent years, we have learned that this is not the case. Deep sleep and full wakefulness lie at the extremes of a spectrum, and implausible as it may sound, it is possible for us to be in both states at the same time.” 

Alex has given permission for his story to be told, as has Jackie, a septuagenarian who sleep-rides her motorbike; Claire, a chronic insomniac; and Adrian, who falls asleep when he laughs. And then there’s Don, a sleep-eater for 40 years. Desperate, he once locked his fridge – only to find on waking that he’d eaten his parrot’s bird seed. He is one of Leschziner’s more intractable patients.

It might sound hilarious but, to patients like Adrian and Don, their sleep disorders are a life-altering nightmare.

A good night’s sleep is crucial to a sense of well-being. You can, the doctor points out, survive longer without food than without sleep; and yet its importance to mental and physical health has been slow to find acceptance among the medical establishment.

This is beginning to change. Today, sleep medicine harnesses not only neurologists like him but also respiratory physicians, psychiatrists, cardiologists, psychologists, ear, nose and throat surgeons and even dentists. The range of specialists working on sleep is a sign of its immense complexity. Basic questions, such as why we dream, are still unanswered.

One reason may be the poverty of tools at the researcher’s disposal until now. Their mainstay is a machine first used in the 1920s – the electroencephalogram (EEG). It defines the different stages of sleep by monitoring the electrical signals of the brain to reveal the tell-tale brainwaves of, for example, deep sleep. But the device, which uses wires stuck with glue to the scalp, is like using a snorkel and mask to explore the Mariana Trench, says Leschziner. The technique, he says, “tells us next to nothing about what is going on in the vast depths of the brain”.

Sleep medics like him now have a growing arsenal of new tools. The EEG has been joined by a rack of sensitive devices that measure airflow, and chest and body movements. Magnetic resonance imaging (MRI) and positron emission tomography (PET) let him see, however fuzzily, inside the brain, and genetic testing is linking some sleep disorders to genetic mutations. “These tools were totally unimaginable a few years ago.”

Although this science is still an emerging one, Leschziner’s case histories often record a happy ending. The doctor is a patient listener, dogged detective, and comes across as an honest reporter of his own treatment strategies and mistakes. Each case history is revealing, not only about the patient and the science behind their problem, but also, in an almost accidental way, of the kindly, droll doctor-writer.

“After a few more night rides, Jackie gave her motorbike keys to her landlady for safekeeping, and later sold it. She still misses her BSA 250. ‘Brilliant bike! You can hear that coming for miles.’ I tell her it is surprising that it did not wake her up. ‘It is, isn’t it?’ she says.”

Can’t sleep?

  • Roughly a third of adults report periods of poor sleep, making it by far the most common sleep disorder. About one in 10 adults has insomnia serious enough to make them tired and irritable during the day. It can be a sign of an over-active thyroid gland, a side effect of medication, or of issues such as anxiety or depression. The link between sleep and mental health is poorly understood, says Leschziner.
  • You might well be getting better sleep than you think you are. Even those with severely broken sleep can actually be getting a normal amount of restorative deep (stage 3) sleep. “We are often unreliable witnesses to our own sleep.”
  • True “short sleep” insomniacs often have elevated markers of stress hormones such as cortisol and adrenalin in their urine. These hormones indicate “fight or flight” stress and fear processes. Symptoms can include a racing heart and dilated pupils. These patients are literally terrified of their bedroom. “Importantly, these changes are not seen in people with insomnia who are getting a reasonable amount of [deep] sleep.”

Sleep state misperception

“It is incredibly common after [a sleep study] to hear “I slept terribly that night”, although the study will show a decent night’s sleep of seven hours. The person is adamant they only slept an hour or two. Something about the way this person experiences sleep is different. It may be as simple as the brain filling in time between the brief awakenings of normal sleep, perceived as wakefulness by someone predisposed to this form of insomnia.”

Sleep deprivation

Insomnia and sleep deprivation are often conflated, says Leschziner – but they are opposites. “If you study someone who is sleep deprived in the sleep lab, they doze off very quickly, and while they are awake they perform poorly in tests of vigilance. In stark contrast, ‘short sleep’ insomniacs will be hyper-vigilant, and will take longer to fall asleep in the lab.”

Health risks of insomnia

When the risk of conditions such as high blood pressure, Alzheimer’s and diabetes are analysed in people with insomnia, says Leschziner, those with “properly measured” short periods of deep sleep have higher rates, while those sleeping six hours or more have no increased risk at all. High blood pressure and diabetes may turn out to be linked to chronic, measurably high levels of stress hormones (elevated by-products of these can show up in urine) that cause an intense state of anxiety called hyperarousal, preventing sleep. This is not sexual arousal, but a corrosive form of alertness, nervousness and vigilance.

How much sleep is enough?

“This question,” says Leschziner, “is similar to asking, ‘What is the normal height for a 10-year-old?’ If I look at my daughter’s class photo, the children range in height hugely, but all of them are normal. Likewise, there is a range of normal sleep requirements. It depends on your genes, and the quality of your sleep. The right amount of sleep is the number of hours needed for you to wake up refreshed and not sleepy during the day.”

Sleep trackers

If you are sleepy during the day, or need to catch up in the weekend, you are probably not getting enough sleep, and Leschziner suspects you won’t need a sleep tracker to know this. “These devices are at present relatively inaccurate. Apply five different trackers to your arm and you will get five widely diverging estimates of your sleep duration. If you are already worried about your sleep because you have insomnia, then constantly tracking your sleep can intensify your obsession with your sleep and make the problem worse.” For most people, he says, sleep is a subjective experience, and a tracker telling you that you slept poorly when you expected to be told you slept well can “in itself have profound effects on your own perception of your sleep”.

Sleep Glossary

Chronotype
The tendency to be a “morning person” or a “night owl”. This can change as we grow.

Circadian
Sleeping is a biological process, which uses this 24-hour cycle. We get jet-lag when it is out of whack. Some people inherit an inner clock set to a different cycle, which causes disastrous sleeping habits.

Stage 3 sleep
Deep sleep, also called “slow wave sleep”. This happens mostly in the first half of the night, and is thought to be particularly important for health and wellbeing. The most difficult time to rouse someone is when they’re in this stage of sleep. Adults spend around 15-25% of their sleep in stage 3 sleep; this diminishes slightly as we age.

REM sleep
The stage of sleep associated with dreaming. There is paralysis of almost all muscles, rapid side-to-side eye movement, and an active brain state. Adults usually cycle through four or five cycles a night of each state: stage 1 (drowsiness), stage 2 (light sleep), stage 3 (deep sleep), and REM sleep.

REM sleep behaviour disorder
Loss of paralysis of the muscles in REM sleep, resulting in the acting-out of dreams.

Non-REM parasomnias
Conditions that cause abnormal behaviours such as sleepwalking, night terrors, sleep-talking or sleep-eating, arising within non-REM sleep. Sleepwalking is common in children but rarely persists into adulthood – only 1-2% of adults sleepwalk.

This article was first published in the June 2019 issue of North & South.

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