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Stage one is the lightest sleep. While someone is in stage one sleep, they are easily awoken by loud noises like a car horn outside or even a very loud commercial from another room. Stage one sleep is a peaceful and calm sort of sleep. Your muscles are relaxed and your eyes are closed during this time. Your heart rate and blood pressure start to slow during this time. Your body temperature also slowly drops as well. If you aren’t awakened during stage one sleep, you move on to stage two sleep. During stage two, you aren’t as easily awakened from sleep. It takes more than a loud commercial to wake you up now. Contractions and muscle spasms can jerk your limbs during this stage of sleep. The first two stages usually average about thirty minutes. Your brain waves become deeper and begin to slow. Your blood pressure and your body temperature continue to steadily decline. Stage three sleep is actually a short transition stage that comes right before stage four sleep. Deep sleep and delta sleep are common names for stage four sleep. While you are in deep or delta sleep, you are completely unaware of the world around you. Your brain waves are now slower still. During delta (deep) sleep, you don’t sweat or shiver no matter how you hot or cold you may be. You can only be awakened by major disturbances during this stage, like a fire truck driving by with its sirens on. Delta (deep) sleep is the most restful stage of sleep; it is also the stage that was most critical for growth (especially for teenagers). You see, while you are in delta (deep) sleep, a special hormone that controls growth is released. The first time you experience delta (deep) sleep each night, it usually takes a half hour to an hour and a half, sometimes even longer. Stage five sleep, also commonly known as REM (rapid eye movement) sleep. REM sleep is important because it is the one stage that you experience dreams. You might wonder why it is called rapid eye movement sleep. Well, the answer is that while you are dreaming, your eyes constantly move. Your dreams are like little movies that are projected onto your eyelids, so your eyes are always moving to take in all of the dream and know everything that’s happening. While in REM sleep, your heart rate and blood pressure increase because your brain is busy creating dream after dream so it needs more oxygen and blood circulating your body. REM sleep doesn’t last long, for the first stage of the night, and it usually takes 5-10 minutes. However, REM sleep is commonly repeated 4-5 times each night. Each sleep cycle then averages about 90 minutes after the first. There is one other important thing about REM sleep, during this stage; there is increased blood flow to the thalamus. The thalamus is a part of the brain located deep inside near the sleep center of the brain. It acts as a relay station by sending messages back and forth between the brain and spinal cord. The amygdale may also play a part a large part in dreaming. So now you know everything there is to know about the five stages of sleep. Sleep tight, don’t let the bed bugs bite! |
| The FIVE Stages of Sleep |