It is estimated that adults in modern western societies now sleep one and a half hours less on average than they did a century ago. Statistically, that averages to less than 7 hours of sleep a night, but in reality, only a portion of those hours can truly be accounted for as deep, sound sleep. So why is it that despite working harder, longer and faster, so many of us are finding it increasingly difficult to fall asleep at night, experiencing poor sleep, and then wake up exhausted and frustrated?
For some, the problem lies in taking work back home to complete, often resulting in bedtime anxiety and restlessness. Others are unable to get a good night’s rest due to sleep disorders (e.g. sleep apnea or insomnia), chronic pain, medications or other health conditions.
Amongst the younger crowd however, the chronic lack of sleep tends to revolve around socialising, media and electronic devices – and often all at once. Using laptops and computers for movies, games, emails and social net-working, as well as mobile texting and calls are all common pre-sleep distractions. In fact, studies have shown that checking and replying to emails, or reading up the latest gossip on social network sites just before bed has the same effect on the excitatory system as drinking a double espresso! This effectively heightens brain activity and heart rate, making the individual restless just before bed and unable to drift into a deep sleep. Furthermore, prolonged exposure to the lights from a television set, mobile phone or a laptop (which in reality flashes at high speeds too fast for the naked eye to conceive) is intense enough to discourage any production of melatonin – a chemical in the brain that is released upon sensing darkness and induces a state of drowsiness.
Now burdened with a lack of sleep, we proceed to face our tasks for the new day, only to find that we’re less astute, grumpier and probably spending too much time staring at the added wrinkles on our face and droopy eye bags that weren’t there the day before. It’s obvious that sleep deprivation impacts us on both a mental and physical level, and when prolonged, can cause detrimental health consequences.
THE EFFECTS OF SLEEP DEPRIVATION ON COGNITION
This topic remains one of the most widely researched areas of psychology and medicine. It is commonly accepted that though the brain may be able to compensate for a lack of sleep over a short period of time, its function undoubtedly decreases over prolonged periods of sleep deprivation.
Studies have shown that a lack of sleep impairs the brain’s ability to exhibit the appropriate emotions in a given situation, often resulting in irrational outburst or frustration. Without sufficient sleep, the receptors of our brains’ neurotransmitters are also unable to regain sensitivity. This causes lower production levels of monoamines – chemicals in our brain which are vital to regulating our moods and concentration. As such, a sleep deprived person will commonly experience increased moodiness, irritability and stress throughout the day. Additionally, sleep deprivation also impairs our attention and working memory, causing concentration lapses in simple routines – even those that we have practiced countless times over. The consequences of this can be trivial, such as forgetting to bring a pen to class, but can also be fatal, such as losing focus whilst driving.
In the long run, prolonged sleep deprivation has been found to disrupt the neurotransmitter balances in the brain, leading to states of depression and anxiety (which has been directly linked to an increase in suicide rate), as well as to the development of serious mental illnesses such as psychosis and bipolar disorder.
THE EFFECTS OF SLEEP DEPRIVATION ON PHYSICAL HEALTH
Not only does the lack of sleep disrupt the neurotransmitter balance in the brain, it also adversely impacts one’s hormonal system. Given that sleep is the body’s time to physiologically rest and recover, the lack of it induces a high state of stress within the system.
The production of cortisol, the stress hormone, causes the breakdown of amino acids (protein) from the muscles in the extremities like the legs and arms, and feeds it to the gut where it is stored as fat (that’s right, the lack of sleep will involuntarily make you fatter!). Cortisol also depresses the production of growth hormone and testosterone (both necessary for maintaining muscle mass and keeping one youthful), weakens the immune system and makes a person more insulin resistant (and thus increasing their chances of metabolic syndrome, diabetes and major fat gain). Furthermore, Studies in the U. S. have shown that when there is an onset of stress, there is a high tendency for people to emotionally eat (especially sweets), as this can temporarily produce a serotonin (‘feel good’ hormone) high, leading to weight gain and obesity – an epidemic that has never been so relevant as in modern society. Other long term effects also include high blood pressure, heart failure and stroke.
In athletes, sleep deprivation has been extensively studied in the context of motor skills and reaction ability, as measured via “Psychomotor Vigilance Tasks” (PVTs). These include areas of mental focus, reaction times and skill set – all of which have proven to be impaired when the athlete lacks sleep.
Sleep deprivation following a heavy training session also slows down the replenishment of glycogen in the muscles overnight, as well as growth hormone production. This has shown to disrupt optimal muscle repair processes and increase DOMs (delayed onset of muscle soreness). That’s not all. The body will also respond to the lack of rest by suppressing muscle building, and instead use up existing muscle stores to fuel low energy levels – a highly catabolic process! Additionally, testosterone (the primary muscle building hormone) and energy levels are likely to be decreased, thus affecting overall strength and performance in version a before feel the next training session.