Shishi junior high school grade 20 15

"Aha" people yawn from the beginning to the end of their lives, especially when they are very tired. Why on earth is this? In order to find out this reason, I went to consult two elders in my family-father and grandfather. But dad and grandpa don't understand, probably because of the needs of the human body! Probably the brain reminds itself that it's time to rest.

I won't stop at such a vague answer. So, I continued to look for information in the library and online. Finally, I found the correct answer: scientists found that it takes about 6 seconds for a person to yawn, during which he closes his eyes and feels comfortable all over. Therefore, it can be considered that yawning can make people get the best physical and psychological relaxation and has an important physiological protection effect on the human body. I heard grandpa say that yawning is a manifestation of brain hypoxia, but it's not like this. On the contrary, by yawning and taking a deep breath, the human body increases the oxygen in the blood and discharges more carbon dioxide, thus making people more energetic.

We all have this experience. We always yawn when we feel sleepy. This is the brain reminding the human body that it is tired and needs sleep and rest. Therefore, yawning is actually a hypnotic method. I don't know if you have noticed that we often yawn before we enter the intense work, such as before important exams, before large-scale speech contests, and before cultural performances. At this time, we may complain that we are not focused enough, nervous enough and in a bad state. Don't worry, it's actually not a bad thing. At this point, our spirit is in a state of tension. Yawning means that the human body increases more oxygen in the blood by deep inhalation, which improves the activity ability of the brain, thus promoting the functional area of the cerebral cortex from inhibition to excitement and making the cerebral cortex work better. According to this principle, I guess: if we are about to enter a stressful job, we can take a deep breath like yawning, which can help us relax and adjust our bodies to a better state.

You see, as long as we discover and ask questions, there is so much knowledge hidden in a little yawn! I must study hard and gain more knowledge through continuous exploration, and then I can discover more mysteries.