While statistics vary by country, sleep deprivation is a very common problem in most countries. Most adults report receiving less than seven hours of sleep per night, and this practice of sleeping less is also seen to be very common in students studying in high school, and those in undergraduate and graduate studies. The prevalence of this problem has encouraged a lot of research on the effects of sleep deprivation on health. The research then shows an association between sleep deprivation and significant health problems, like mood disorders, and cardiovascular disease.

“The research then shows an association between sleep deprivation and significant health problems, like mood disorders, and cardiovascular disease.”

There are several theories as to why getting adequate sleep is required: for body rejuvenation and repair, memory consolidation, and energy conservation and restoration. To put it simply, sleep is required to keep the body healthy and functional.

Rejuvenation of the body occurs every night during the sleep cycle. This sleep cycle is divided into multiple stages of sleep deepening:

Stage one, where the brain waves look very similar to when a person is awake, is when the individual is drowsy and is falling asleep.
Stage two is a little deeper than stage one, where the spindles and K-complexes are important for a good sleep.
Stage three is when the body transitions into a slow wave sleep, which is a really restful deep sleep.
Stage four is even deeper and slower than stage three.
An individual ideally enters REM sleep, which is associated with dreaming, after stage four. In this stage, the brain waves resemble those of being awake since there is so much activation in the brain.

Cortisol (your body’s stress hormone) plays a major and direct role in the execution of this sleep cycle, as it helps to regulate sleep. Levels of cortisol decrease in sleep stage stage three, as the stress response calms down in your body and halts the secretion of more cortisol. It then begins to rise again an hour before you have to wake up, and will continue to rise during the day until levels peak and begin decreasing again half way through the day. The decrease in these levels towards the end of the day, once again, induces sleep, continuing the sleep cycle. However, not sleeping causes the cortisol levels to continue rising (and by extension the stress levels), and disrupt slow wave sleep in sleep stage three by disrupting memory consolidation.

Studies have found that this stress and increasing cortisol levels can negatively affect the immune system. It can also significantly increase the risk of cardiovascular disease by damaging the artery walls resulting in increased blood pressure and plaque build-up in the heart. This research has shown that blood pressure can be greatly impacted if a person experiences sleep deprivation for even one day.

Increased cortisol levels due to lack of sleep can also significantly affect mental health. Studies have shown that anxiety and depression often came hand in hand with restricted sleep, and that lack of sleep and prolonged stress can alter the brain to resemble those seen in mood disorders. One study presented that reduced sleep, less than six hours, increased the likelihood of drug use, poor grades in school and school problems, poor perceived health, low life satisfaction and mental health problems like depressed mood and anxiety. It was also found that lack of sleep and depressed mood have a reciprocal effect on one another, meaning that reduced sleep leads to depression and subsequently, depression leads to sleeping less.

Sleep deprivation also strongly impairs cognitive functioning and the ability to acquire new information, consolidate it to long-term storage, and retrieve it later. Sleep is crucial in preparing the brain to acquire new information, and it is important in memory consolidation after learning. Judgement and decision-making processes can also be impacted: there are changes in sensation seeking, reward processing, impulsivity, and risk taking, when these areas are deprived of sleep, which leads to impaired decision making. A sleep deprived individual would not be able to properly weigh the costs and benefits of a decision. Maintaining attention becomes increasingly erratic and irregular, resulting in the failure to attend to one stimulus while ignoring distractors, and task execution becomes inconsistent. Sleep loss results in a general slowing of response speed and an increased variability in performance, and also significantly affects divided attention, as it becomes progressively worse if the number of tasks increase.

Emotional abilities and mood become considerably disrupted due to lack of sleep as well. Moods such as volatility, irritability, aggression, and anxiety can be enhanced because of lack of sleep, and even a single night of sleep loss shows a significant increase in negative self-rated mood scores. There is also evidence of heightened negative thoughts and impatient responses to frustrating social situations.

The importance of sleep for a person’s mind and body cannot be ignored. As we can see there are a number of ways sleep deprivation can impact someone, and dealing with sleep deprivation on your own can feel overwhelming. This is where a trained health practitioner can support you, whether it’s a therapist trained in Cognitive Behavioural Therapy for Insomnia (CBT-I) and stress management, or your family doctor who can support you with lifestyle and medication changes.

If you or someone you know would like to support in dealing with your sleep and stress issues, our team at The Growth & Wellness Therapy Centre can help. Please contact our intake and administration team to set up a free consultation with one or more of our clinicians.

The Effects of Sleep Deprivation on Your Physical and Mental Health