好多人生日
有小学的朋友
中学的朋友
大学的朋友
及亲戚
我
只能呈上短短的祝福
却没机会帮他们庆祝
再次
祝你们“生日快乐”!!!

Good morning to everyone. My name is Yann Ling. Today i would like to share a speech about “The stages of sleeping”.
Do you sleep every day?? Have you ever thought of what are the stages of sleeping? Have you dreamt before?? Do you know how do your dreams occur?? And in which stage of sleep do you start dreaming??
Although sleep may seem like a steady state, it actually consists of five stages that cycle throughout the night. One complete sleep cycle lasts about 90 to 100 minutes; therefore during an average sleep period a person will experience 4 to 5 complete sleep cycles. The sleep cycle begins with four stages, called NREM (Non-REM) and REM (rapid eye movement) sleep.
"REM" stands for "Rapid Eye Movement", while NREM stands for Non Rapid Eye Movement. REM is the phase of sleep where the brain is the most active and the most numerous and vivid dreams occur.
After introducing about the simplest stage of sleeping, do you feel curious about the stages of sleeping??
Today, let me share more about the stages of sleeping.
Stage 1
Stage 1 is a light sleep. You can be easily be woken up and your eyes and body movements will slow down. This period of sleep lasts only a brief time (around 5-10 minutes)
Stage 2
During this stage, eye movement stops and your brain waves become slower. There will also be brief bursts of rapid brain activity called sleep spindles. Additionally, body temperature starts to decrease and heart rate begins to slow down.
Stage 3
Stage 3 is the first stage of deep sleep. The brain waves are a combination of slow waves, known as delta waves, combined with faster waves. During this stage of sleep it can be very difficult to wake someone up. If you are woken up during this stage, you may feel groggy and disoriented for several minutes.
Stage 4
Stage 4 is the second stage of deep sleep. In this stage the brain is making the slow delta waves almost exclusively. In this stage it is also very difficult to wake someone up. Both stages of deep sleep are important for feeling refreshed in the morning. If these stages are too short, sleep will not feel satisfying.
Stage 5
The next stage, stage 5, is where REM sleep takes over. REM sleep is the sleep stage in which dreaming occurs. When you enter into REM sleep, your breathing becomes fast, irregular and shallow. Your eyes will move rapidly and your muscles become immobile. Heart rate and blood pressure increase. Dreaming occurs due to increased brain activity. So, when you start dreaming, you have reached the fifth stage of the sleep cycle. Some people think that they don’t dream, but actually, they do. It’s just that they don’t remember it.
After completing these five stages, a cycle is complete. As I said earlier, an average human will have a few complete sleep cycles. Actually, at the end of each cycle, many people actually wake up briefly. Most people don’t even remember this. However, some poor sleepers may wake fully.
In conclusion, I’ve shared with you the five stages of sleeping. After describing the sleep cycle to you, I hope that you realize how important sleep is for a person. A teenager actually requires at least nine hours of sleep a night to wake up fresh in the morning. Perhaps, you can give this a thought and get more sleep.
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