VOA慢速英语2014 How to Survive the Heat

 

How to Survive the Heat

From VOA Learning¹ English, this is Science in the News.

I’m Anna Matteo.

And I’m Christopher Cruise².

Today we talk about hot weather, and the problems it can cause. We also tell you about the best ways to prevent and treat problems caused by extreme heat.

Heat Waves Can Be Deadly

Floods, storms and other natural events kill thousands of people every year. So does extreme heat. In fact, heat may be nature’s deadliest killer³.

Several hot days that follow each other are considered a heat wave. Experts say heat waves often become dangerous when the nighttime temperature does not drop much past the highest daytime temperature. This puts great pressure on the human body.

Extreme heat can be harmful to very young children -- especially when they are left in a car. Every year, there are news reports about young children dying⁴ after they were left inside cars in the summer sun.

Jan Null is a meteorologist -- a weather expert -- at San Francisco State University in California. Since 1998, he has recorded deaths of children from what medical experts call “vehicular heatstroke.” He says the United States has an average of 38 such deaths each year of children left alone in cars. 

Mr. Null told the USA Today newspaper that the highest number of deaths take place in July and August -- the two hottest months of the year. He said about nine children die in each of those months because they were left in a hot car. But he notes that vehicular heatstroke can happen any time of the year. He says a child can die from the heat after being left in a car when the outside temperature is as low as 14 degrees Celsius⁶.

USA Today reports that 70% of vehicular heatstroke victims were children under the age of two. It says more than half of the deaths happened because the child’s caregiver forgot the child was in the car. About one-third of the deaths happened when the child got in the car and was unable to get out of it.

The newspaper notes the temperature inside a car can reach 43 degrees Celsius when the temperature outside is 14 degrees. And it says the body temperature of a child can increase three to five times faster than adults.

How to Protect Yourself and Others in Extreme Heat

Doctors say people can do many things to protect themselves from the dangers of extreme heat. Stay out of the sun, if possible. Drink lots of cool water. Wear light-colored clothing, and hats made of natural materials.

Make sure the clothing is loose, permitting freedom of movement. Also, learn the danger signs of the medical problems linked to heat.     

The most-common health problem linked to hot weather is heat stress. Usually, it is also the least severe.      

Most people suffer only muscle pain because of heat stress. The pain is a warning that the body is becoming too hot. Doctors say those suffering muscle pain should stop all activity and rest in a cool place. They should also drink cool liquids. Doctors say not to return to physical activity for a few hours because serious conditions can develop. 

Hot weather is dangerous for people who weigh too much and have too much body fat, and for people who drink alcohol⁷. It also increases dangers for people who must take medicine for high blood pressure, poor blood circulation⁸, nervousness or depression.

Untreated heat stress can lead to a more serious problem called heat exhaustion⁹. A person suffering from heat exhaustion loses too much water through perspiration¹⁰. He or she will feel weak and extremely tired. They may have trouble walking normally¹¹. Heat exhaustion may also produce a fast heartbeat, breathing problems and pain in the head, chest or stomach. Doctors say people with such problems should rest quietly in a cool place and drink plenty of water. They also say it may help to wash with cool water.       

Experts say even a two percent drop in the body's water supply may cause signs of dehydration¹². These signs include problems with memory and even simple mathematics. The treatment for dehydration exhaustion is the same as for heat exhaustion. Drink plenty of water and rest in a cool place. Even better, doctors say, drink about two liters¹³ of water a day so problems with dehydration will not have a chance to develop. 

Heat exhaustion can lead to heat stroke⁵ if it is not treated. Heat stroke is the most serious disorder¹⁴ linked to hot weather. It results when the body is not able to control its temperature. The body temperature increases and perspiration fails.

Signs of Heat Stroke, and How to Treat the Condition 

Generally, the body temperature rises to more than 40 degrees Celsius. The body stops perspiring¹⁵. The skin becomes dry and very hot. A person may become unconscious, not knowing what is happening.   

Doctors say tissues¹⁶ and organs begin to cook when the body's temperature is higher than 42 degrees Celsius. Permanent brain damage and death may result. Someone suffering heat stroke requires immediate¹⁷ medical attention. Doctors say such treatment is necessary or the person could die before help arrives.

The purpose of immediate treatment is to cool the victim as quickly as possible to stop the temperature from increasing. Begin by moving the victim out of the sun. Raise the person’s feet up about 30 centimeters. Take off the victim’s clothing. Put cool water on the body. Place pieces of ice in areas where blood passageways are close to the skin. These include the back of the neck and under the arms.         

Experts say it is important to know the danger signs of the medical disorders¹⁸ linked to hot weather. It is also important to know what to do if the signs appear in yourself or in someone else. 

The Importance of Water

Experts say water is important for many reasons. Between 55 and 75 percent of the body is water. Water in blood carries hormones¹⁹ and antibodies throughout the body. Water in urine carries away waste materials. Water is needed for cooling the body on hot days, and when we are working or exercising. Water carries body heat to the surface of the skin. There, the heat is lost through perspiration.

Health experts say adults should drink about two liters of water a day to replace all the water lost in liquid waste and perspiration. They say people should drink more than that in hot weather.

Experts say it is important to drink before, during and after exercise. They say we should drink water even before we start to feel like we need something to drink. During hot weather, cool liquids are best. Also, avoid sweet drinks and alcohol.   

We need to add that doctors also say it is possible to drink too much water. Some people, for example, do this if they exercise hard during a heat wave. Experts with the Mayo Clinic say drinking too much water can cause hyponatremia. In this condition, the level of sodium²⁰ in the blood falls too low. 

The result is that the amount of water in the body increases. This causes cells to become larger. Mayo Clinic experts say the enlarged²¹ cells can cause a person to become sick or restless²². They also can interfere²³ with mental ability, make muscles weak and cause pain in the head. In a mild case, simply reducing fluids²⁴ may be all that the person needs. But medical help is necessary if the condition is more severe.

Experts have suggestions for runners and others exercising or working hard in hot weather. They say drinking a sports drink with sodium in it can help prevent the condition.    

Doctors say actions other than drinking water can protect against the health dangers of heat. Stay out of the sun, if possible. Wear loose, lightweight and light-colored clothes. Wear a hat or other head covering when in the sun. Eat fewer hot and heavy foods. If possible, cook foods during cooler times of the day. Also, rest more often. Physical activity produces body heat.

Experts say these simple steps can prevent the health problems linked to heat. They will prevent sickness, help you feel better and may even save your life.

1 learning   

n.学问，学识，学习；动词learn的现在分词

参考例句：

• When you are learning to ride a bicycle,you often fall off.初学骑自行车时，常会从车上掉下来。
• Learning languages isn't just a matter of remembering words.学习语言不仅仅是记些单词的事。

2 cruise   

v.巡航，航游，缓慢巡行；n.海上航游

参考例句：

• They went on a cruise to Tenerife.他们乘船去特纳利夫岛。
• She wants to cruise the canals of France in a barge.她想乘驳船游览法国的运河。

3 killer   

n.杀人者，杀人犯，杀手，屠杀者

参考例句：

• Heart attacks have become Britain's No.1 killer disease.心脏病已成为英国的头号致命疾病。
• The bulk of the evidence points to him as her killer.大量证据证明是他杀死她的。

4 dying   

adj.垂死的，临终的

参考例句：

• He was put in charge of the group by the dying leader.他被临终的领导人任命为集团负责人。
• She was shown into a small room,where there was a dying man.她被领进了一间小屋子，那里有一个垂死的人。

5 stroke   

n.笔画，击打，连续的动作，中风，心跳；vt.奉承，轻抚； vi.击打，心跳...

参考例句：

• He drove in a nail with one stroke of the hammer.他一锤就把钉子敲进去了。
• He broke the lock with one stroke of the hammer.他一锤就把锁砸坏了。

6 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

7 alcohol   

n.酒精，乙醇；含酒精的饮料

参考例句：

• The law forbids shops to sell alcohol to minors.法律禁止商店向未成年者出售含酒精的饮料。
• The alcohol is industrial.这些酒精是供工业用的。

8 circulation   

n.循环，流通，传播，发行，发行量

参考例句：

• There is a large circulation in the musical public.在音乐界销路很广。
• The ideas have been in circulation for some time.这些想法已经流行了一段时间。

9 exhaustion   

n.耗尽枯竭，疲惫，筋疲力尽，竭尽，详尽无遗的论述

参考例句：

• She slept the sleep of exhaustion.她因疲劳而酣睡。
• His exhaustion was obvious when he fell asleep standing.他站着睡着了，显然是太累了。

10 perspiration   

n.汗水；出汗

参考例句：

• It is so hot that my clothes are wet with perspiration.天太热了，我的衣服被汗水湿透了。
• The perspiration was running down my back.汗从我背上淌下来。

11 normally   

adv.正常地，通常地

参考例句：

• I normally do all my shopping on Saturdays.我通常在星期六买东西。
• My pulse beats normally.我脉搏正常。

12 dehydration   

n.脱水，干燥

参考例句：

• He died from severe dehydration.他死于严重脱水。
• The eyes are often retracted from dehydration.眼睛常因脱水而凹陷。

13 liters   

n.升( liter的名词复数 )

参考例句：

• In the metric system, measurements are made in metres and liters. 在公制中，用米和升作计量单位。 来自《简明英汉词典》
• This can holds five liters of water. 这个容器可装五升水。 来自《简明英汉词典》

14 disorder   

n.紊乱，混乱；骚动，骚乱；疾病，失调

参考例句：

• When returning back,he discovered the room to be in disorder.回家后，他发现屋子里乱七八糟。
• It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。

15 perspiring   

v.出汗，流汗( perspire的现在分词 )

参考例句：

• He had been working hard and was perspiring profusely. 他一直在努力干活，身上大汗淋漓的。 来自《简明英汉词典》
• So they "went it lively," panting and perspiring with the work. 于是他们就“痛痛快快地比一比”了，结果比得两个人气喘吁吁、汗流浃背。 来自英汉文学 - 汤姆历险

16 tissues   

n.组织( tissue的名词复数 )；薄纸；棉纸；一套

参考例句：

• The teacher showed the students the pictures of brain tissues. 老师给学生们看脑组织的图片。 来自《简明英汉词典》
• Give some face tissues to me. 给我些面巾纸。 来自《简明英汉词典》

17 immediate   

adj.立即的；直接的，最接近的；紧靠的

参考例句：

• His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
• We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。

18 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

19 hormones   

n. 荷尔蒙，激素 名词hormone的复数形式

参考例句：

• This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
• The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。

20 sodium   

n.（化）钠

参考例句：

• Out over the town the sodium lights were lit.在外面，全城的钠光灯都亮了。
• Common salt is a compound of sodium and chlorine.食盐是钠和氯的复合物。

21 enlarged   

扩大( enlarge的过去式和过去分词 )； 扩展； 扩充； 放大

参考例句：

• The balloon enlarged as we pumped air into it. 那个气球充气后就变大了。
• The castle was enlarged considerably in the fifteenth century. 这个城堡在15 世纪得到了相当大的扩展。

22 restless   

adj.焦躁不安的；静不下来的，运动不止的

参考例句：

• He looks like a restless man.他看上去坐立不安。
• He has been very restless all day and he awoke nearly all last night.他一整天都心神不定，昨夜几乎一整夜没有合眼。

23 interfere   

v.(in)干涉，干预；(with)妨碍，打扰

参考例句：

• If we interfere, it may do more harm than good.如果我们干预的话，可能弊多利少。
• When others interfere in the affair,it always makes troubles. 别人一卷入这一事件，棘手的事情就来了。

24 fluids   

n.液体，流体( fluid的名词复数 )

参考例句：

• He is taking cold fluids. 他正在喝冷饮。 来自《简明英汉词典》
• You can contract Aids if your bodily fluids come into contact with the bodily fluids of someone else who is infected with HIV. 如果你的体液与染有HIV者的体液接触，你就会染上艾滋病。 来自《简明英汉词典》