Sleep Facts
The new year is often a time when people think about the year ahead and what is important, including personal wellbeing. If you have spent some time recently reflecting on your goals for wellbeing, have you thought about sleep? If your answer is in the negative, you are not on your own. Diet and exercise tend to be at the top of peoples’ wellbeing goals, while the pivotal role of sleep is overlooked.
SOME INTERESTING FACTS ABOUT SLEEP: Sleep is a universal phenomenon - humans and animals cannot exist without sleep. Dolphins must constantly move, so one half of their brain sleeps at a time while the other half stays awake to maintain movement. Once one half has slept, it switches on to allow the other half to doze off. Elephants need only four hours of sleep per day – half as much as humans.
Sleep is fundamental to health. Because modern technology has enabled people to stretch the boundaries of waking hours, many people suffer from insufficient or disrupted sleep. This has implications for physical and mental health. Disordered sleep is common to many mental illnesses, including depression, post-traumatic stress disorder and dementia.
In healthy people, sleep is inevitable and is regulated by two hormones - melatonin and adenosine. Melatonin acts as a signal generator, sending a message to the brain that it is time to sleep. But melatonin doesn’t make us sleep. This is the job of adenosine, which acts like a chemical pump that builds up pressure during waking hours, creating a desire to sleep. It acts like a bank – when the mortgage is due, we must make payment or face the consequences. When we feel sleepy, it is because the adenosine build-up is reminding us that a sleep instalment is due.
Caffeine is a stimulant that keeps us awake by blocking the effect of adenosine. However, the sleep debt must be paid at some stage. Feeling drowsy before midday is a sign that you are not getting enough sleep.
We need sleep to learn. Sleep allows the brain to undertake a range of functions necessary for good brain health – including washing the brain, remodelling neural circuits, organising storage space for new information. This helps us retain (via memory) all the information that we need to make our way in the world. All of this takes approximately eight hours in adults, but much longer in babies, children and adolescents.
Sleep helps creativity. During REM (rapid eye movement) sleep, many of the emotional regions of the brain become active, with associations (i.e. dreams) being made between new information and information in long-term memory storage. “Sleeping on a problem” makes sense and often we awake with a solution or insight that seemed previously elusive. During sleep, our brain has “joined the dots”.
IMPROVING SLEEP: Create a healthy sleep routine. Try to regulate sleep according to your body’s natural clock. Going to sleep and waking up at the same time creates a good “sleep habit”.
Prefer books to screens before bed. LED-powered devices (e.g. tablets) suppress melatonin release and disrupt REM sleep. Late-night catching up on work emails might make it harder for you to recall information the next day.
Avoid over-heating. A cooler room temperature is better for sleep.
Moderate caffeine and avoid alcohol before bed. Although alcohol is a sedative, it disrupts the brain functions that regulate sleep. Alcohol suppresses REM sleep, which can have serious consequences for brain health over time.
Retrain your brain. Cognitive Behavioural Therapy is recommended as a first-line treatment for insomnia. It targets the mental (or cognitive) factors such as the racing thoughts and worry that are part of sleep difficulties and the behavioural factors that help create the right environment for sleep, helping the mind re-establish a positive anticipation about sleep.
There is much more to sleep than we might imagine. If you are having difficulties with sleep, think about improving your sleep habits. If problems persist, have a chat with your GP.
