We all sleep. It’s as much a part of being human as breathing or drinking water. If we don’t get enough sleep, the negative effects become immediately apparent. It’s harder to concentrate, our response time slows down significantly, and as for remembering things––well, it’s hard to know what you had for breakfast that day.
Sleep is essential. There is much speculation as to why, but one thing’s certain; we need it. Each time we sleep, we go through a series of stages. It’s crucial that we pass through each of these in order to wake up feeling refreshed and ready to start our day. So, what are these stages of sleep?
You lie down, curl up under your blankets, and begin to drift off. Suddenly, you feel as though you are falling. Or, you find yourself randomly twitching. These phenomena, which include mild hallucinations occur during the pre-sleep stage.
This non-REM stage of sleep is defined by the transition from wakefulness to sleep. It lasts only a short time, and during this stage, your heartbeat, breathing, and eye movements decrease. Your muscles relax, and your brain waves begin to slow. If you’re awakened during this stage, you likely won’t even know that you were asleep.
Your heartbeat, breathing, and eye movements slow significantly during this non-REM stage. Your muscles relax further, and your body temperature even drops. Your brain displays brief electrical bursts of activity. You spend more of your sleep cycles in this stage than any other stage of sleep.
Deep Sleep/Delta Sleep
Have you ever woken up feeling just as tired, or like you haven’t slept at all? You likely didn’t reach this stage of sleep. You need to reach this stage in order to wake up feeling refreshed. This non-REM stage occurs in longer periods during the first half of the night. During this stage, your heart rate and breathing slow to their lowest. Your muscles relax and it becomes difficult to awaken you. Your brain waves slow even further.
So, what exactly does REM mean? This acronym stands for “Rapid Eye Movement.” During this stage, your eyes begin to move rapidly behind closed eyelids. Your brain waves resemble those during wakefulness. Your breathing becomes fast and irregular, and your blood pressure increases to your normal awakened state. Most of your dreams occur in this stage, and your muscles become almost paralyzed in order to prevent you from acting out your dreams. Curiously, as we age, we spend less time in this stage of sleep.
Even though we might not be aware of it, a lot happens while we sleep. We need both non-REM and REM sleep in order to wake up feeling well-rested and functional. Almost every creature on earth needs to sleep, and as humans, we spend quite a lot of our lives in this state. Hopefully, this blog has helped you to better understand what occurs between the time we lie down and shut our eyes and when we are startled awake by the blare of our alarm clocks.