Funny I decide to blog about sleeping when I should be sleeping right now. What can I say? I’m a true night owl (it’s when I do my best work, really!).
Now, not to sound cryptic, but I rarely dream now a days. However, last night I had a very unsettling dream, which I suppose you would call a nightmare. Long story short, I was being chased around and someone ended up shooting me in three vulnerable places. A very vivid, frightening experience.
So when exactly do nightmares or “night terrors” occur?
According to my Psych prof, nightmares are a uniquely human experience. It occurs in during Stage 4 of sleeping cycle, which is only observed in humans.
Of course, now with that being said, I can’t just not explain what stages of sleep exist for resting the human mind.
First, let’s define what sleep is.
Sleep is considered an altered stage of consciousness. This implies that the mind is still active in some way. It is absolutely necessary to get sleep since it is the way for to rest the mind and the body after depleting energy during the day (if you are diurnal like most humans).
This is a cute image from HowStuffWorks.
The Sleep Cycle for Humans:
- Non-REM Stage 1:
You know that point when you have hopped into bed for a few minutes, and your eyes are closed and relaxation washes over? Welcome to Stage 1 of sleep.
- Non-REM Stage 2:
Now you might think that you are still awake, however, at this point you will be starting to ignore minor events around you (like the tv or radio being on). It occurs about 15 minutes into your sleep. At this point, I could probably still wake you diverting your attention (ie- saying your name), though as you go deeper into the sleep cycles, your ear muscles will rapidly move to protect the auditory nerve from sound waves while you try to rest. Also at this point, your time perception will be skewed (ie- time is going faster than normal or much slower than normal). Most animals, like cats, do not go further than Stage 2 of sleep.
- Non-REM Stage 3:
And now “slow wave” sleep occurs when delta waves now appear. This is one of the most important stages of sleep that is the longest in the cycle. I associate this with the tissue build and recover stage, which is energy expensive. Only primates, like great apes, get to this stage of sleep.
- Non-REM Stage 4:
Another slow wave sleep stage, so it is like Stage 3 in importance. Only humans reach this deep stage of sleep! It is evolutionary the newest of all the sleep stages. While dreaming occurs throughout all cycles of sleep, this the only stage where nightmares occur. It is also where emotional processing takes place.
- REM Stage:
“Rapid eye movement sleep” – named because the scientist who observed this in his baby daughter saw her eyes moving while in this stage. However, during REM less than 50% of the time the eye actually moves. This is where the brain grows and develops, consolidating memory. Your muscle tone is also lost in this stage so you don’t go reenacting your dreams (although I’m not sure why sleep walking occurs…another blog maybe?)Here is a more typical Sleep Cycle graph.
How much sleep should you get?
- WebMD suggests at least getting 7-8 hours of sleep a night as an adult, and more hours of sleep if you are younger.
Best napping strategy?
- Break up naps in 1.5 hour (or 90 minute) increments. It’s best to wake up during the REM stage if you want to wake up feeling rejuvenated and alert! If you wake up during a slow wave sleep stage, you will feel very disoriented and exhausted.
- My Psych 101 class (haha)