Source of pictures:pixabay.com
One day in July, thescorchingsunlightwas caston the earth.When youlooked up,there was a burning sensation on your faceandpea-size sweatdrippingdown.Peoplewent out withsun creams.David’sfamily decided to go swimmingat the weekend.
Afterputtingon hisswimsuit, David wentto the poolin haste.Hejumped into the water anddivedlike a fish.The coldwaterinstantlydrove awaythe irritabilitybroughtby thesummerheat. Hismotherwasstanding at the pool and shoutingat him, "David, wait forus.Don't swim to the deep water area alone!" Shehad changedon herswimsuitas well.
At this time,Davidgot outof the water, waved tohismother, and said, "I am here!Don't worry.I'm doingwell!"Then hismother jumped into the water, and swam towardhim. Suddenly,hefelthisleft foot was crampedandhad nostrength. After struggling for awhile,hisbody sank into the water.As he stayed in the deep water area, the sudden feeling of fallingterrifiedhim.Hewanted toshoutforhelp, only to be choked witha few mouthfuls of water. At this time, there was a big hand in front ofhim.Liftedup byan upward force,hecouldfinallybreathethe fresh air again.He turnedaroundand found itwashis dad.Hecoughed alittle bitand said, "That was close! I thought I would sink to the bottom."
Hismother also swam to the shore.Afterpulling himashore,shewas worried and said,"I just told you not toswim in the deep water area aloneagain and again. If you drowninthedeep water area, it will be very dangerous."Hewanted to answer,but he was stopped withcough.His motherpatted his back andcontinued,"When people are submerged under water, water may enter the lungs. At this time, the vocal cords maygo into severe spasm,which willtemporarily prevent water from entering the lungs, but also hindersbreathing. In this case, the lungs cannot transport oxygen to the blood, causing hypoxia. Moreover, water entering the lungs can also causeinjuries,especiallythe watercontaminated bybacteria, algae, sand, dirt, chemicalsandvomit.So drowning is very dangerous."
"What's more," Dad put a blanket onhim, andcontinued,"In severe cases,a person's skinwillturn tobluewhen heissaved after drowning. This is called cyanopathycaused by lowoxygen concentration.In a betterscenario, peoplewill cough and retch as youdo. However, the human body also has a protective mechanism. Itcan bufferthe damagetosomeextent.In other words,cold water canprovokeswimming reflex.It helpsusto survive in cold waterfor a longer time."
Davidfinallyrecoveredand askedwhileshivering,"Dad, what isswimmingreflection?"His dadexplainedpatiently,"Swimmingreflection will slow heartbeat and let blood flow from the hands, feet and digestive tract to heart and braintoprotect these vital organs."
Henodded and said,"Isee.I willneverswim alone in the deep water area."
Author: Lu An
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