An Introduction to Sleep
Many people do not know how many hours they should be sleeping each night, though they may be keenly aware of how few hours of sleep they get each night. Some even fool themselves into thinking that they can operate well on five to six hours of sleep, even though science tells us it will have a detrimental effect on our health, memory, ability to communicate, and concentration levels. The research is very definitive that the optimal amount of sleep for adults is between seven and nine hours.
There is one particularly important piece of research by the University of Pennsylvania that carried out a wide-scale study to test how long a human can go without sleep before their performance is impaired. A series of reasonably simple concentration tests were designed to measure response, and reaction times were measured. Different control groups were set up, each of which was allowed additional sleep throughout the experiment.
The control group, who were only allowed six hours of sleep a night, performed considerably worse than those who were allowed eight hours. Ten days of six hours of sleep a night was all it took to become as impaired in performance as going without sleep for 24 hours straight.
People often shave off time from their sleep when busy, but this should be the last thing to go. It’s counterproductive as output and quality of work will decrease.
Sleep cycles
There are two different sleep cycles - REM (rapid eye movement), when dreaming happens and NREM (non-REM), which is deep sleep. These sleep cycles alternate throughout the night, up to five or six cycles a night, with each sleep cycle lasting around 90 minutes long. Both of these cycles of sleep have different but equally essential functions.
There is generally a higher proportion of deep sleep phases at the beginning of a night’s sleep and more REM sleep towards the end, typically in the morning. Going to bed later than usual for just one night will reduce the amount of deep sleep, just like waking up earlier than usual reduces REM sleep.
REM Sleep
REM sleep helps to regulate emotional activity – a critical emotional intelligence skill.
Think back to when you were sleep-deprived and ask yourself: did you find that your patience with other people had decreased? Or were you quick to snap at others?
This is all down to the ability or inability to regulate our emotions when sleep deprived. It’s a core emotional intelligence skill that is compromised when one doesn’t have enough REM sleep. This sleep phase also helps people to read the emotions of others accurately.
Sleep scientists believe that people dream of stripping away any emotional trauma from experiences during the waking day, which helps people process the trauma and move on from it. Research has shown that when people dream about the emotional themes and sentiments of the waking traumas experienced, even if it’s not in a literal way, they are much more likely to gain resolution and overcome the trauma. Evidence suggests that the REM sleep of PTSD sufferers is disrupted, limiting their ability to strip away the emotional pain of their trauma and leading to recurrent nightmares.
REM sleep also helps with creative problem-solving and idea generation, so if you’re trying to be creative at work, you want to ensure you get a good night’s sleep.
NREM Sleep
In comparison, NREM cycles, or what is also called the deep sleep phases, are responsible for memory consolidation.
Have you ever wondered why you forget someone’s name moments after they tell you?
The brain has a temporary storage centre for new information called the hippocampus. When people receive information, it goes to the hippocampus before it is initially recalled. The hippocampus, however, has limited storage space, so during the deep sleep phase of sleep, the brain transfers these memories into an area of our brain called the neocortex, which then moves them into retainable memories. This is a much bigger space where lots more information can be stored and turned into long-term memories.
Without sufficient deep sleep, the brain cannot carry out this process of ‘banking the memories’ sufficiently, which means the hippocampus stays full. This is why you might forget someone almost instantaneously after they introduce themselves. There might not have space in your temporary brain storage to put that new information. Over time people also forget a lot of the new things learned as the process of memory banking isn’t happening as frequently as it should.
Various studies have shown that the more NREM sleep people have, the more information they remember the next day (from what was learned the day before), which makes deep sleep incredibly important. Most deep sleep happens towards the beginning of the night’s sleep, meaning that going to bed later in the evening reduces some essential deep sleep phases.
Deep sleep is also responsible for a large amount of physical health. It is responsible for a crucial part of cardiovascular health, motor skills, immune system recovery, and activating the parasympathetic nervous system, which is the nervous system component responsible for rest and recovery.
A study about sleep’s impact on cardiovascular health noted that during the daylight savings time adjustment in March (when the clocks go forward), there is always a spike in hospital records for heart attacks the following day. They also found that in October, when the clocks go back, the heart attacks drop the next day. The difference of losing an hour of sleep can affect cardiovascular health quite dramatically.
Overall, sleep is essential to taking care of physical and mental health. Sleep helps people process emotions, put things into memory, and rest and recover their bodies. Next time you consider skipping a few hours, consider these effects on your health.
