We’ve all had those late nights, or early starts to the day that keep us from getting those essential eight hours of “shut eye”.
A study of over 1,000 people by The Sleep Health Foundation found that over 40% of respondents reported having poor sleeping patterns.
We convince ourselves that we can operate on only a few hours of rest, but even after a single night of poor sleep, we begin to experience a range of symptoms. These include fatigue, irritability, and even dozing off during the day.
Poor sleep is also linked to poor memory and recall functions, an inability to focus on tasks at hand, and even increased risk of depression, anxiety, and other forms of mental stress.
Studies have demonstrated that artificial light after sunset can disrupt and delay the onset of circadian cycles, which in part explains why some people have difficulty falling asleep at night.
Insomnia is a recognized sleep disorder, characterized by difficulties falling asleep, and then further difficulties staying asleep. It’s estimated around a third of all Australians will have a period of insomnia during their lives, sometimes lasting for months or even years.
Insomnia can be the result of an underlying mental health disorder, such as anxiety or depression, but can also exacerbate other mental health disorders.
How many hours of sleep are required for optimal functioning?
Unfortunately, the answer isn’t always simple. As well as light-induced disruptions to the circadian rhythm, our natural sleep-wake cycles change with age.
Typically, in adolescence and early adulthood, around nine hours of uninterrupted rest is required to feel refreshed. In adulthood, around eight hours is required, and in the elderly, seven hours of sleep is usually sufficient. The hours we tend to sleep also change with age, getting earlier and earlier as we get older.
When we fall asleep, our brains undergo a number of cycles, cycling between two phases known as random-eye movement (or REM) and non-random eye movement (or NREM) sleep.
Our vivid dreams occur in REM, and light disturbances may wake us up, whereas NREM is deep sleep. It is during NREM that our body undergoes essential tissue repairs and our immune system becomes reenergized.
Although we may appear peaceful while we rest, there are a vast number of neurological processes taking place in our brains. One of these important processes is known as memory consolidation, which converts a short-term memory to a long-term memory. This in part explains why people have trouble remembering things after a night of poor sleep.
Functional magnetic resonance imaging (fMRI) studies, which analyse activity in the brain, demonstrate reduced regulation of our emotional centres. This means, simply, that we have less conscious control over our emotions after a lack of sleep.
Other studies have shown people tend to experience negative emotions (for example, sadness and anger) more when they are tired. These negative emotions can appear even when presented with photographs of things that wouldn’t normally elicit anger or sadness.
It isn’t surprising that sleep deprivation and mental health issues, such as depression and anxiety, are closely linked. That isn’t to say poor sleep is the cause of depression and anxiety, but they often go hand-in-hand.
For example, people often report having difficulty falling asleep due to anxious thoughts. But then, because their brain misses the opportunity to strengthen connections with the emotional centres, the anxiety may be worse the following day. It easily becomes a vicious cycle of emotional deregulation and tiredness.
While sufficient sleep won’t necessarily ‘cure’ depression or anxiety, getting enough hours of rest will certainly aid in regaining balance over emotions. It may be that you are able to think with clarity, and have better conscious control over emotions. This can be as simple as consciously recognizing when your emotions are negative, which may be difficult when you’re tired.
It’s easy to see the importance of a good night’s rest, but it is easier to tell someone they need more sleep than it is to actually help them get to sleep.