On a personal level, sleep is incredibly frustrating. Wasting around about seven to eight hours of every single day of our adult life on, it seems like a colossal waste of time to us, when there is so much fun to be had while we are conscious. But, it is difficult to deny that the vital health benefits that regular, as well as unbroken, proper sleep – as elusive as that is – brings about.
Sleep deprivation (SD), whether it is international or inadvertent, takes them away. And it is indubitable that you will miss them the moment when they are gone. So, let’s journey, step-by-step, through what you enjoy when you sufficiently snooze. Let’s see what the myriad effects of a total loss of sleep may be, with the caveat that some of these effects remain decidedly enigmatic.
As it is well-known, people go through various phases of sleep, which form a part of multiple cycles. When you engage in rapid eye movement (REM) sleep, you dream, and maybe sleep-walk or talk. But, this just makes up a small portion of your presumably nocturnal activities.
For the majority of your snoozing, about 75% or so, you enter non-rapid eye movement (NREM) sleep that comes in three different phases.
During the first one, you fluctuate between being awake and asleep and not too much occurs to you on a physiological level. However, some of you may experience hypnic jerks, which are sudden muscle spasms which may shake you awake.
When the second on happens, sleep begins in earnest, and you also become unaware of your surroundings. Breathing and heart rate remain regular, but your core body temperature drops. And the third one, however, colloquially referred to as “deep sleep,” is where all the good stuff tends to happen.
As your blood pressure drops and stays low, it also boosts cardiovascular health. Your muscles relax, your breathing also slows, and the blood supply to your muscles increases. Tissue growth and repairs are prioritized, and hormones that are vital to your proper functioning are released, including also those which regulate feelings or hunger.
The hippocampus, which deals with memory consolidation, among other things, shows plenty of electrical activity, as you slumber. Even though much remains unclear, some recent studies have suggested that short-term memories acquired throughout the day seem to be progressively transferred to the cortex for long-term “storage” at night.
Something which falls away immediately after just one less night of sleep is those all-important cognitive reasoning and retention functions. From grammatical reasoning and spatial planning to memory recall activities, our abilities start to drop off to varying degrees.
It seems that there is far less activity going on in the frontal and parietal lobes. It also deals with problem-solving, as well as decision making. As it was noted by a landmark 2017 review on the subject, your visual cortical regions also show an increasingly reduced signal over time. This happens during the visual working memory tasks. Reaction times, as well as learning also fall by the wayside.
The reward system of the brain is also shown to be sensitive to SD.
This can cause some changes in how a person seeks our risks, as well as sensations, and takes impulsive actions. Essentially, the more SD you experience, the more of a clumsy fool you will likely become.
One review from 2017 also notes that based on the “limited evidence to date,” SD starts to trigger reductions in the “intrinsic connectivity profile” of the brain. This essentially means that the wiring linking up parts of our brain become less effective. Another separate study highlights that brain cells themselves are less able to communicate with each other as well. This is another of the main reasons why you become physically uncoordinated as SD worsens.
This, together with reduced blood flow to said regions, is thought to be connected to not just cognitive, but also “emotional impairments.”
A piece on the phenomenon over at LiveScience also explains that SD makes the person less able to display positive emotions. Furthermore, the person is less able to recognize them in others. Negative emotional experiences also become increasingly harder to deal with as the days go on. And some people may even experience a state of delirium and hallucinations too.
Whether or not they are true, full-blown hallucinations or merely ephemeral flickers in their peripheral vision are up for debate. But either way, the brain is going to be less able to process sensory information as times ticks by.
Physical health is inextricably linked with mental health as well.
Those people who sleep well are far less likely to experience depression, as well as anxiety and some other related mental health problems. In the absence of it, such afflictions may also appear or worsen if they are already present.
SD also means that those feeling of famishment-controlling hormones are not being released in quite the same way either. Moreover, your body also stops metabolizing glucose efficiently. As Slate noted, you are consequently going to desire more carbohydrates than necessary. This may also indirectly lead to weight gain.
Even with just a single sleepless day in tow, cortisol, as well as thyroid-stimulating hormone levels rise, triggering a higher blood pressure. In the long term, poorer cardiovascular health probably awaits you.
Often, we forget the health of our immunities. A good night’s sleep permits our body to promote the production of cytokines. That is a family of proteins that are vital for communication between cells. Similarly, solid snore-sessions permit you to maintain normal levels of immune cells and associated antibodies as well.
Over time, through SD, it is likely that your capacity to fend off infections is going to begin to falter as its immune responses are suppressed.
Some evidence in mice also suggests that sleep may even “flush” toxins out of the brain. Experiments show that the space between our critter cousins’ brain cells increases during the unconscious night by up to 60%.
When this happens, cerebrospinal fluid floods through the valleys, in that way clearing out toxic byproducts which are connected with neurological impairments, as well as far more serious neurodegenerative disorders. In the long term, SD – or chronic sleep loss – could potentially increase the risk of gaining said disorders in a person later in life.
A day-by-day account of what is happening to an individual is difficult to elucidate upon.
This is because such experiments are also difficult to maintain in the long run, and people will respond differently to sleep loss. Is the end always the same though? Would a near-perpetual SD experience always end in death?
It is also possible, but there is still not enough data to say one way or the other. The detrimental health impacts would probably finish you off if you managed to keep going. But, there is almost no way in which this is possible as you would increasingly struggle not to fall asleep no matter what you are doing to try to prevent that. Your brain is forcefully going to start to shut down. Anecdotal evidence of humans dying after 11 days then, is not reliable data points.
Curiously, as it was described by The New York Times, in one set of SD experiments on rats, those that were deprived of sleep, died in 2.5 weeks. Those that were deprived of just REM sleep took twice as long to perish. Importantly though, it is not clear what was the specific cause of death. It is still not completely clear why, in many different aspects, sleep is so necessary for our continued survival.
In any case, you do not need to undergo total SD to live through such a hellish life. For some temporary disruption to insomnia, much of civilization is sleep deprived. And we are also sleepwalking into a health-based nightmare as a result of that.