Who doesn’t like to sleep off to their land of nod? But not many of us know what exactly is happening when we are at our nightcap. Read on to find out what happens internally when we get our ZZZs. While buzzing off, we cycle through two stages: non-rapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep. And it goes without saying that our body and mind act up differently in each phase.
Non-rapid eye moment is also known as quiet sleep. While REM is also called active or paradoxical sleep.
The Sleep Cycle
During the earliest phase, we are relatively still awake and alert. (The brain produces Beta waves, which small but fast). Eventually, our brain begins to slow down and relax. (Slower waves are emitted called Alpha waves). During this time, we are not quite asleep. We may experience strange vivid sensations. Which we call hypnagogic hallucinations. Common examples of this phenomenon include feeling like you are falling or hearing someone call your name. Myoclonic jerks are also common at this period. This is when our body suddenly startles for seemingly no reason at all.
NREM Stage 1
This is the beginning of the cycle and is a relatively light stage of sleep. This can be considered a transition period from wakefulness.
NREM Stage 2
This is the second stage and lasts approximately 20 minutes. During stage 2, one becomes less aware of the surroundings. Which in turn cools down our body, dropping the body temperature. Also, the breathing and heart rate becomes more regular.
NREM Stage 3
During this stage, our muscles start to relax, while dropping the blood pressure and breathing rate. This is when the deepest slumber occurs.
This stage is also sometimes referred to as delta sleep. During this stage, people become less responsive. Noises and activities in the environment may fail to generate a response. It also acts as a transitional period between light and very deep sleep.
During REM the brain becomes more active. The body becomes relaxed and immobilized. At this stage, our eyes move rapidly.
REM is also referred to as paradoxical sleep because while the brain and other body systems become more active, muscles become more relaxed. Dreaming occurs at this stage, due to increased brain activity, but voluntary muscles become immobilized.
Once REM is over, the body usually returns to stage 2. Sleep cycles through these stages approximately four or five times throughout the night. It’s important to know that the progress isn’t necessarily in the same sequential order. Sleep begins in stage 1 and progresses into stages 2 and 3. After stage 3, stage 2 is repeated before entering REM.
Far from being a state of doing nothing, sleep is an essential part of our lives. It helps our body rest, recharge, and repair. Getting enough of it is important for promoting healthy activities in the body such as growth, digestion, memory, etc. There is no magic “number of hours” that works for everybody of the same age. Not dozing long enough, or dozing at odd times of the day with exposure to bright light at night can disrupt your internal clock and the many processes it regulates.
Additionally, though you may think you’re getting ample rest, not all are created equal. It’s not only essential to get enough hours of sleep every night but also important to get a good quality one. Nevertheless, there isn’t a consensus regarding what defines sleep quality.
However, it may be determined by how long it takes you to fall asleep, how often you wake up during the night, how rested you feel the next day, and how much time you spend in different stages of sleep. Since it is essential for so many aspects of good health, one should emphasize high priority in getting enough sleep every night.