Dreams and Sleep
After being awake all day, or night if you're a shift worker, we all need a period of sleep to restore our energy and take away the aches and pains accrued during our waking activities.
When we sleep most of our systems go on stand by or switch off altogether, our metabalism is working very slowly so that we can use our sleeping energy reserves to boost our immune system and fight infections and repair injuries while we sleep. Without sleep none of this would be possible, or it would at least be severely impaired.
No one has ever died from lack of sleep, however the efficiency of our physical and mental functions is significantly reduced if we go without our required sleep.
Everyone requires a different amount of sleep, with babies needing sleep the most at around fifteen hours per day and older people the least with as little as three or four hours a day. For most of our lives though we require around eight hours of sleep per day, some people need a bit more and some a bit less but eight hours is thought to be the standard for a good night's sleep.
Recent research has shown that dreams are also an essential part of our restorative systems. When we sleep only our automatic, essential bodily functions are still running, and even our brains are on a limited energy budget, with all areas closed down apart from the ones needed to stay alive. With this in mind it seems clear that dreaming must be an essential function, all non-essential functions are closed down while we sleep, therefore dreaming must be an essential function.
Some think that the physical purpose of dreams is to keep our brains active while we are otherwise unconscious, like keeping a car ticking over with the motor running in case we need to quickly move back into wakefulness - a sort of survival mechanism that helps us leap into action right away instead of waiting for our brains to 'boot up' like a computer that's been switched off.
REM (Rapid Eye Movement) Sleep
Eugene Aserinsky and Nathaniel Kleitman are credited with discovering REM Sleep in 1955, so it's no wonder that most people are familar with the term and it has in fact being written about thousands of times already. So much so that I almost feel that it is not necessary to write about it here, mostly because I do not like rewriting time-worn ideas when there is an abundance of material already in existance. However, I have to bow to the facts that no self-respecting article on dreams and sleep can overlook mentioning REM sleep and at least give it a breif allusion. If I left it out readers would probably assume I didn't know what I was talking about, so here it is.
Aserinsky and Kleitman made many sleep studies, watching volunteers while they slept and monitoring their brain activity. They were working at a time when scientists had pretty much discounted the value in such studies, believing there was nothing new to learn from observing humans while they sleep. However, these two sleep specialists observed that every one of their subjects displayed curious movements of the eyes when they were in an early period of sleep. The eyes moved around in an odd fashion, underneath the closed lids, as if they were seeking out some unseen presence.
From utilizing their various monitoring techniques and machines they discovered that during these periods of strange eye movement there was also an increased amount of blood flowing to the brain and that the sleeper's breathing and heartbeat often became irregular, as if they were experiencing some kind of physical movements, though there was also a reduction in electricity flowing to the muscles in this period.
By waking people up during this REM period of sleep they found that most subjects were able to give vivid account of dreams they'd just had. On the other hand, people who were forcibly awoken at other stages of sleep rarely remembered their dreams and in over ninety percent of cases they were unaware of having dreamt anything at all.
Brain waves were observed by Aserinsky and Kleitman to be short and spikey while being awake, jumping around like one might see on a polygraph machine, or 'lie detector'. However, as we fall deeper into sleep our brainwaves become longer and more even like rolling waves on a calm ocean.
Stages of Sleep
1. Hypnogogic - is the sleep stage that is closest to wakefulness. We enter this stage when we first close our eyes, feeling sleepy and perhaps seeing images and dream-like movies before our eyes, though we are still at a stage where our mind is still active. We may feel floaty and relaxed, while remaining aware of where we are. Drifiting into this stage can take about ten minutes, with the spikiness of waking brainwaves are being rounded off and turned into Theta Waves.
2. In the second stage of sleep the brain produces Spindle Waves, which occure in rapid bursts and are accompanied by the lowering of body temperature and slowing of the heart. This stage lasts about twenty minutes.
3. Stage three sleep in a transitional period between light sleep, where if woken you may deny you were asleep, and deep sleep where the brainwaves are beginning to flatten out into Delta Waves.
4. Delta Sleep, so named because Delta Waves are fully formed by the brain, is the deepest stage of sleep and when sleepwalking can occur, and involuntary bed-wetting in children and sometimes people who drink too much alcohol. It is thought that Delta Sleep is when the body repairs itself
5. REM Sleep is the fifth stage, the time when we are most likely to dream.
As we sleep we go back and forth through these sleep stages, like a tide coming in and out, in what is known as Sleep Cycles. In an eight hour period of sleep we will usually go through four sleep cycles with the dreaming REM periods becoming longer with each repetition.
During REM Sleep our muscles have chemicals in them that makes it impossible to move so that we cannot act out things we experience in our dreams and hurt ourselves. It is thought that the phenomena of Sleep Paralysis (where you feel unable to move, like a large weight is pressing down upon you) is a result of experiencing wakefulness while the body still has some of the muscle paralyzing chemicals in place.