Sleep tight, don’t let the sleep debt bite!
Writers: Viktorija Vaitkeviciute and Eugenia Wong
Editor: Altay Shaw
Artist: Sophie Maho Chan
Working throughout the night and functioning on only a few hours of sleep is often joked about amongst students. However, the startling consequences of these habits to the human body are astonishing. Surveys have found that around 22% of people living in the UK have trouble falling asleep every night and 15% struggle at least once a week. Sleep deprivation affects our health, social, educational and professional functioning.
Yet many of us often consciously make the decision to prioritise work and function on very little sleep. We hope that this article will raise awareness about the importance of sleep. Even if you feel fine in the morning, continuous sleep deprivation inflicts grave consequences.
What happens to the body when we sleep?
You may think that sleep is a passive state of both mind and body, but it is in fact the opposite. We experience two forms of sleep: rapid eye movement (REM) and non-rapid eye movement (NREM). Throughout the night, REM and NREM alternate cyclically over the course of a sleep with each cycle lasting approximately 90 minutes.
Sleep typically begins with NREM sleep, a deep state of sleep characterised by a progressive decrease in brain activity, eye movement and skeletal muscle tone. It consists of three stages; of particular importance is stage 3, as it is the period during which the body repairs and regrows muscles and tissues, stimulates growth and development, and promotes immune function. The arousal threshold is the highest at this stage, meaning that it is the most difficult period to be awakened from. Waking up during this period will result in a short period of mental fogginess and impaired mental performance known as sleep inertia – which is why we may feel groggy and sleepy after taking too long a nap.
NREM sleep is followed by REM sleep, where electrical activity in the brain heightens, accompanied by increased blood flow to the brain. Our breathing rates become irregular and shallow and our muscle tone decreases (which is believed to prevent us from acting out our dreams). It is also the stage in which dreaming and memory consolidation occur.
Cycles of NREM and REM sleep over the course of a 7-hour sleep in a young adult. Taken from Sleepopolis.
A study published in Nature suggested that improved quality, length and consistency of sleep correlated with better academic performance. Despite our limited understanding of the relationship between sleep, memory and neuroplasticity, it is believed that during sleep, the synaptic connections that were active during wakefulness are strengthened. This consolidates what we have learnt, which is essential for academic development.
Interestingly, it was found that simply having a good night’s sleep the night before an exam was not related with better exam scores. Rather, sleeping well throughout the content learning process (‘content-relevant sleep’) was better associated with higher achievement, further supporting sleep’s fundamental role in learning and memory consolidation.
Insomnia and sleep difficulties
Let’s take a look at what happens to the body when we do not get enough sleep. Insomnia is a sleep disorder characterised by difficulty falling asleep, frequent waking during the night and waking up too early in the morning. This leads to impaired working memory, attention switching and social function during the day, which in turn results in mental distress and reduced quality of life in the individual. It is different from sleep deprivation as insomniacs have the opportunity to sleep but are still unable to do so. Most people with insomnia talk about racing thoughts and worrying excessively when asked about why they cannot sleep. This is a result of an increase in cortical, cognitive and somatic activation in the central and peripheral nervous systems. The prevalence of sleep deprivation in adolescents and adults is increasing, often due to educational/ occupational demands and family dynamics. Sleep deprivation and the subsequent build-up of sleep debt have deleterious physiological and psychological effects. Short term consequences include heightened blood pressure and inflammatory markers.
Mood disturbances, such as anger, depression and anxiety, are also common responses to sleep deprivation. Sleeping for less than 7 hours per night is correlated with obesity, as it is associated with lower levels of leptin and higher levels of ghrelin, hormones that suppress and stimulate appetite respectively.
Insomnia treatment aims to improve the quality and quantity of sleep and minimise daytime impairments. The pharmacological treatment includes benzodiazepines, ‘Z drugs’ (zolpidem, zaleplon and eszopiclone), antihistamines and melatonin.
The sedative-hypnotic effects of benzodiazepines and Z drugs are mediated by their binding to the inhibitory gamma aminobutyric acid (GABAA) receptor. Because of the receptor’s inhibitory effects on the brain, the individual is able to relax and wind down, which eventually results in sleep. Z drugs are more commonly prescribed than benzodiazepines, as their side effects are less severe. For example, they pose a lower risk of respiratory depression, cognitive impairment and fatigue, and have a reduced potential for tolerance and dependence. Mirtazapine is a H1 histamine receptor antagonist, so decreases the stimulatory effect of histamine on the brain, promoting sleep.
Melatonin is a hormone that is essential for sleep regulation and produced by the pineal gland. It is used to treat insomnia induced by jet lag and night shift work. The non-pharmacological treatment, cognitive behavioural therapy, is also used to treat insomnia and sleep difficulties. This would include practising relaxation techniques, reducing caffeine intake and increasing daily exercise. Individuals who are not suffering from insomnia also gain from practising these techniques when trying to improve the quality of their sleep.
As students, we understand that sometimes it seems like a good idea to stay up late and work, however, giving yourself a good night’s sleep and a well deserved break could prove more productive than working through the night. The next time you push aside sleep in favour of finishing an assignment, maybe think again. It may be better for both you and the assignment to call it a night and start afresh the next morning. Sleep tight, don’t let the sleep debt bite!