SLEEP, LIKE THE weather, is one of those easy topics of conversation. People like to compare and contrast. It is estimated that around one in three people regularly experience insomnia, with the elderly particularly at risk. Insomnia can vary in how it presents; some find it hard to fall asleep, while some experience a broken pattern of constantly waking up. Others wake up early in the morning and are unable to get back to sleep.
It can leave you feeling unrefreshed next day – tired, irritable and unable to concentrate. For some people, insomnia comes and goes in episodes without causing any real problems; for others, it can have a serious impact on relationships and quality of life. It may even be a sign of illness.
Such illnesses might include obstructive sleep apnoea (OSA), where the upper airway keeps closing during sleep, causing loud snoring or even pauses in breathing that keep waking the person up. In the doctor’s surgery, the person might complain of morning headache or excessive daytime sleepiness. Unsurprisingly, OSA correlates with road traffic accidents because people fall asleep behind the wheel.
Other medical reasons for poor sleep include heartburn, thyroid problems, restless legs syndrome (an irrepressible urge to move the legs to avoid discomfort, often worse at night), any cause of significant pain, some types of medication, and various psychiatric illnesses such as mania, depression, anxiety disorders and post-traumatic stress disorder (PTSD). This is not an exhaustive list.
Not getting enough sleep can be frustrating and leave us exhausted the next day. Alamy Stock Photo
Alamy Stock Photo
Sleep and psychiatry have been comfortable bedfellows for well over a century. The Austrian neurologist and founder of psychoanalysis, Sigmund Freud, wrote extensively about dreams being a form of “wish fulfilment” that expressed unconscious desires that were sometimes unacceptable or repressed in real life. Seeing dreams as the “royal road to the unconscious”, Freud did a lot of dream work with his patients, analysing the storyline or imagery of dreams (the “manifest content”) to highlight their hidden psychological meaning (or “latent content”).
As a psychiatrist, I occasionally get asked by a patient to interpret a dream. But, like many of my colleagues, I tend to reply apologetically that we don’t really do that anymore. Instead, we focus on sleep to help with diagnosis.
For example, an inability to fall asleep (or “initial insomnia”) suggests an anxiety disorder, while recurrent nightmares are common with PTSD. “Early morning wakening” suggests depression, while people with mania typically experience a dramatically reduced need for sleep at all. Although some psychotherapists will explore dreams in a less-strictly-“Freudian” manner, they tend to focus on dreams by way of processing daily events, memories, stressors and emotions rather than unconscious desires per se.
Having put that one to bed, it’s worth considering why do we sleep at night at all. At nighttime, especially as the dark evenings draw in, the brain (specifically the pineal gland) naturally produces more of the hormone melatonin. This makes us more inclined to want to sleep.
Indeed, lots of other hormones change predictably over a twenty-four hour period in what is called the circadian rhythm. These include growth hormone (higher during sleep), thyroid-stimulating hormone (higher during sleep and lower in the afternoon) and cortisol (rising rapidly in the middle of the night and peaking next morning). This helps to explain why you will feel jet lagged if you fly home from the other side of the world; your mind may have caught up with the new time zone, but it will take your body a week-or-so to adapt.
Strangely, we don’t have to go back too far to find sleep patterns quite different to what we see today. Back in the Middle Ages, people would typically sleep twice in a twenty-four-hour period – a pattern known as biphasic (or segmented) sleep.
This involved a primo somno (“first sleep” or “dead sleep”) beginning at dusk. At around midnight, they would wake for an hour or two (a period referred to as the “watch”) and pray, read, chat, have sex or do a few light chores around the house. Then they would return to bed for secundo somno (or “second sleep”) until dawn. This practice was documented in medieval literature, diaries and court records, but gradually disappeared from popular use with the Industrial Revolution and the advent of artificial light. Of course, the Spanish still enjoy a nice siesta if it gets too hot in the afternoon.
Either way, we spend around a third of our lives sleeping. Newborn babies need up to 17 hours per day, while teenagers need eight 10 hours and adults need seven to nine. A nights’ sleep typically occurs in four to five sleep cycles, with each lasting 90 to 120 minutes, divided into REM (rapid eye movement) and non-REM sleep.
Dreaming time in an average night’s sleep can add up to the length of a feature film. Alamy Stock Photo
Alamy Stock Photo
Non-NREM is divided into three stages (N1, N2 and N3) of gradually slowing brainwave activity.
N1 is the shallowest stage and lasts just a few minutes shortly after we nod off. Our heart rate and breathing slow down, our muscles relax and our eyes move slowly. N2 is light sleep that makes up the largest total amount of our slumber. Our heart rate and breathing slow further, our body temperature falls, and our eyes stop moving. N3 is the deepest stage when we are hardest to rouse. Our heart rate and breathing are at their slowest and we have no eye movements at all. During N3, the body takes the opportunity to repair cells and tissues and strengthen our immune system.
Finally, we enter REM, when we do most of our vivid dreaming. It could be regarded as the time when the brain does its filing.
Think of the brain as a kind of old-fashioned open-plan office in, let’s say, an insurance firm. During the working day, scores of clients are seen by agents and underwriters, and all the while files are retrieved from filing cabinets and piled on desks.
Then 5.30pm arrives and everyone goes home. Enter the night crew, the filing clerks whose job it is to return all the files into the correct filing cabinets. To get it right, they must glance at the contents of the files, perhaps cross reference them with older files and so forth.
As our brains engage in REM sleep, the filing of daily events, memories, stressors and emotions is experienced as dreaming.
REM naturally involves rapid eye movement, but also faster heart rate and breathing, and increased brain activity. Our muscles (except eye muscles, obviously) are paralysed during this stage. If they weren’t, we would be prone to acting out our dreams.
Some people experience a minute or two of REM at the very start of sleep before non-REM begins, but REM begins in earnest at the end of the first sleep cycle, around 90 minutes after we fall asleep.
The first REM session lasts around 10 minutes, increasing with each cycle to 30 to 60 minutes just before we wake. We dream a feature-film’s-worth each night, but it is skewed because we have more REM during the second half of the night. Indeed, up to half our REM is during the last hour, so cutting back your sleep from seven to six hours may mean losing up to half your nights’ all-important REM. Best to aim for at least seven hours.
But what do you do if you simply cannot sleep?
Well, here are seven suggestions, the first six of which fall under the term “sleep hygiene”.
- Timing: Regularise your sleep schedule by aiming to rise and retire at predictable times every day. This strengthens your body’s circadian rhythm.
- Space: Cultivate a cool, dark, quiet, and comfortable bedroom environment that is reserved for sleep and sex.
- Light: Aim for exposure to natural light in the day and avoid screen time during the hour before bed. The blue light from screens suppresses melatonin.
- Diet: Avoid heavy meals before bed. Note that alcohol may make you tired, but it will worsen the quality of your sleep. If you drink coffee, bear in mind that caffeine has a “half-life” of three to seven hours. This means that if you drink a cup at 6pm, half its caffeine might still be in your body at midnight, keeping you awake. And both caffeine and alcohol are diuretics, which means waking up at night to go to the toilet.
- Activity: Ensure daily exercise but not too vigorous during the three hours before bed.
- Stress: Do your best to manage daily stress. Write your next day’s “to do” list in the early evening and then forget about it. Yoga, progressive muscular relaxation or mindfulness may help you unwind. The average person takes 10-20 minutes to fall asleep so, if you’re still lying awake after 30 minutes, get up, potter or read for a while, and then return to bed and try again. If stress and racing thoughts are persistent in your life, cognitive behavioural therapy (CBT) may help.
- Medicine: If all the above doesn’t work, talk to your doctor. Treating the cause of insomnia may help. For example, OSA can be treated with a continuous positive airway pressure (CPAP) machine. Pain should be actively managed. Mental health issues should never be ignored. In other instances, natural hypnotics such as melatonin may help, although benzodiazepine hypnotics (sleeping pills) are a last resort these days because of their addictive potential. Benzodiazepines need a prescription, usually written with marked caution, and should never be ordered over the internet.
In the end, if you can’t sleep, rest assured help is at hand.
Dr Stephen McWilliams is a consultant psychiatrist at St John of God Hospital, Stillorgan, Co Dublin, a Clinical Associate Professor at the School of Medicine, University College Dublin, and an Honorary Clinical Senior Lecturer at RCSI University of Medicine and Health Sciences.
