SCIENCE IN THE NEWS - How Much Exercise Do You Really Need?

SCIENCE IN THE NEWS - How Much Exercise Do You Really Need?

BOB DOUGHTY¹: This is the VOA Special English program SCIENCE IN THE NEWS. I’m Bob Doughty.
SHIRLEY GRIFFITH: And I’m Shuirley Griffith. Today, we will tell why exercise is so important. And we will tell about some popular ways to get in good shape.
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BOB DOUGHTY: Health experts have long noted² the importance of physical activity. Exercise not only improves your appearance. It can also improve your health. Exercise helps to reduce the risk of some diseases. They include heart disease, stroke, type-two diabetes³, osteoporosis and even some kinds of cancer.
America’s Centers for Disease Control and Prevention says heart disease is the leading cause of death in the United States. In two thousand six, heart disease killed more than six hundred thirty thousand Americans. High blood pressure and high cholesterol⁴ levels in blood can increase your risk of heart disease. Medical experts say both can be reduced through normal exercise.
VOICE TWO: Physical activity is also known to increase the release of endorphins. These chemicals reduce feelings of pain. They also help people feel more happy and peaceful.
There is some debate about exactly what causes the brain to release endorphins. Some experts believe it is the act of exercising itself. Others say it is the feeling one gets from having met an exercise goal.
Either way, the two things work together when it comes to improving one’s emotional health.
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BOB DOUGHTY: Exercise improves your energy levels by increasing the flow of blood to the heart and blood vessels⁵. One of the main reasons people exercise is to control or reduce their weight. Physical activity burns calories – the energy stored in food. The more calories you burn, the easier it is to control or reduce your weight.
So exactly how much exercise do you need to do to gain all of these great health effects? Experts say it is easier than you think.
In two thousand eight, the Centers for Disease Control released its first ever Physical Activity Guidelines⁶ for Americans. The report included suggestions for young people, adults, disabled persons and those with long-term health problems. One of the major ideas noted in the report was that some activity is better than none. So if you are not doing anything, now is the time to get started.
SHIRLEY GRIFFITH: The CDC defines⁷ physical activity as anything that gets your body moving. And, it says there are two separate, but equally important kinds of physical activity. Aerobic⁸ or cardio exercise gets your heart rate going faster and increases your breathing. Some examples are activities like walking at an increased speed, dancing, swimming or riding a bicycle.
Muscle-strengthening activities help build and strengthen muscle groups in the body. This kind of exercise includes lifting weights, or doing sit-ups and push-ups.
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BOB DOUGHTY: To get the most from your exercise plan, experts say adults should get at least two and a half hours of aerobic exercise each week. More intense activities reduce the suggested amount of time to one hour and fifteen minutes. Some examples are playing basketball, swimming and distance running.
Earlier advice from the CDC said people need to exercise thirty minutes each day for at least five days to get the health benefits of exercise. More recent research suggested that those gains are the same whether you exercise for short periods over five days or longer sessions over two or three days.
In addition, the newer suggestions say any exercise plan should include at least two days of muscle training. Each exercise period should be at least ten minutes long. The total amount of activity should be spread over at least two days throughout the week. Most importantly, experts say people should choose physical activities that they find fun. This helps to guarantee that they stay with the program.
SHIRLEY GRIFFITH: So, what are some of the most popular forms of exercise in the United States? Walking tops the list. A two thousand six report from the CDC found that more than seventy-nine million Americans walk to stay physically⁹ fit. For many people, it is considered the easiest way to get exercise. It does not require a health club membership¹⁰. Walking is safe. And it is said be to as valuable for one’s health as more intense forms of exercise like jogging.
Walking is also said to be less damaging to the knees and feet. This makes it a better choice of exercise for older adults.
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BOB DOUGHTY: Another popular form of exercise is jogging, or running at a slow to medium speed. USA Track and Field Hall of Famer Bill Bowerman was credited with bringing jogging to the United States in the nineteen seventies.
He did so after witnessing the popularity¹¹ of the activity himself during a trip to New Zealand in the nineteen sixties. He started the first running club in America and wrote a book about jogging for fitness¹². Bill Bowerman also helped establish Nike, the tennis shoe company.
Jogging provides great physical conditioning for the heart and lungs. And, it increases the flow of blood and oxygen in the body. All of these things combined help to improve heart activity, lower blood pressure and cholesterol levels, and reduce bone and muscle loss. Running is also a good way to lose weight. People burn an average of one hundred sixty calories a kilometer while running.
SHIRLEY GRIFFITH: The Census¹³ Bureau says swimming was the second most popular sports activity in the United States in two thousand eight. The top activity was exercise walking. Swimming is said to be one of the best ways to exercise. Nearly all of the major muscle groups are put to work.
Swimming also presents less risk of muscle and joint¹⁴ injury because of the body’s weightlessness in water. This makes it a great choice of exercise for people with special needs, like pregnant¹⁵ women, older adults, and persons who are overweight.
Some people have questioned whether swimming burns as many calories as other forms of exercise. But one thing is sure: the effects on your health are just as great.
Water aerobics¹⁶ is another popular form of exercise. This can be anything from walking or running against the resistance of water, to doing jumping jacks¹⁷ in the water.
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BOB DOUGHTY: Dancing can also be a fun way to exercise. This is especially true for those who see exercise as a necessary evil: something they should do, not something they want to do.
A dance-fitness program called Zumba has grown in popularity in recent years. Zumba is said to be one of the fastest-growing group programs in the physical fitness industry today.
Alberto Beto Perez created Zumba in his native Colombia in the nineteen nineties. His dance-fitness program is based on salsa, meringue, and other forms of Latin American music. Mr. Perez brought the program to the United States in two thousand one. Since then it has spread around the world.
The Zumba website says its classes are now offered in more than one hundred thousand gyms, fitness studios and dance clubs around the world. That is up from about two thousand locations in two thousand six. The website also says that more than twelve million people now attend Zumba classes in one hundred twenty-five countries.
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SHIRLEY GRIFFITH: Whatever kind of exercise you choose, experts agree that you should start small and work your way up. Start by exercising ten minutes a day two times a week. After a few weeks, increase your time to fifteen or twenty minutes, and increase the number of days.
Next, aim to increase the intensity¹⁸ of your workout. If you have been walking, trying walking faster, or take turns between walking and jogging. And try not to forget those muscle strengthening exercises. The more time you spend exercising, the more health benefits you get.
Health experts advise people who have been physically inactive to have a complete physical exam before beginning a new exercise program. If one of the goals of your exercise program is to lose weight, you will also need to change how and what you eat. Next week we will look at the influence of diet on your weight loss efforts.
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BOB DOUGHTY: This SCIENCE IN THE NEWS was written and produced by June Simms. I’m Bob Doughty.
SHIRLEY GRIFFITH: And I’m Shirley Griffith. Join us next week for more news about science in Special English on the Voice of America.

1 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。

2 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

3 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

4 cholesterol   

n.（U）胆固醇

参考例句：

• There is cholesterol in the cell of body.人体细胞里有胆固醇。
• They are determining the serum-protein and cholesterol levels.他们正在测定血清蛋白和胆固醇的浓度。

5 vessels   

n.血管( vessel的名词复数 )；船；容器；（具有特殊品质或接受特殊品质的）人

参考例句：

• The river is navigable by vessels of up to 90 tons. 90 吨以下的船只可以从这条河通过。 来自《简明英汉词典》
• All modern vessels of any size are fitted with radar installations. 所有现代化船只都有雷达装置。 来自《现代汉英综合大词典》

6 guidelines   

n.指导方针，准则

参考例句：

• The government has drawn up guidelines on the treatment of the mentally ill. 政府制订了对待精神病人的指导方针。
• Planners seem a little uncomfortable with the current government guidelines. 规划师似乎不太接受现行的政府指道方针。

7 defines   

规定( define的第三人称单数 )； 使明确； 精确地解释； 画出…的线条

参考例句：

• This name defines us all. 这个名字造就了我们。 来自演讲部分
• The range of incomes over which this happens defines the 'poverty trap'. 发生在这种情况的收入范围，称为“贫困陷阱。”

8 aerobic   

adj.需氧的，增氧健身法的，有氧的

参考例句：

• Aerobic exercise helps to build up stamina.有氧健身操有助于增强耐力。
• Aerobic dance is conductive to the health.有氧舞蹈有助于健康。

9 physically   

adj.物质上，体格上，身体上，按自然规律

参考例句：

• He was out of sorts physically,as well as disordered mentally.他浑身不舒服，心绪也很乱。
• Every time I think about it I feel physically sick.一想起那件事我就感到极恶心。

10 membership   

n.成员资格，会员全体，从属关系

参考例句：

• I must renew my membership of the sailing club.我必须延续我的航海俱乐部会员的资格。
• He made up his mind to apply for membership in the Party.他决心申请入党。

11 popularity   

n.普及，流行，名望，受欢迎

参考例句：

• The story had an extensive popularity among American readers.这本小说在美国读者中赢得广泛的声望。
• Our product enjoys popularity throughout the world.我们的产品饮誉全球。

12 fitness   

n.适合，适当，健康，健身

参考例句：

• They're doing exercises to improve their fitness.他们为增强体质而做体操。
• No one questions her fitness for the job.没人怀疑她能胜任这项工作。

13 census   

n.(官方的)人口调查，人口普查

参考例句：

• A census of population is taken every ten years.人口普查每10年进行一次。
• The census is taken one time every four years in our country.我国每四年一次人口普查。

14 joint   

adj.联合的，共同的；n.关节，接合处；v.连接，贴合

参考例句：

• I had a bad fall,which put my shoulder out of joint.我重重地摔了一跤，肩膀脫臼了。
• We wrote a letter in joint names.我们联名写了封信。

15 pregnant   

adj.怀孕的，怀胎的

参考例句：

• She is a pregnant woman.她是一名孕妇。
• She is pregnant with her first child.她怀了第一胎。

16 aerobics   

n.健身操，健美操，韵律操

参考例句：

• Doing aerobics is a good way to improve one's health.做有氧健身操是改善健康状况的一个好方法。
• Aren't you going to the aerobics class this morning?今天上午你不是去上有氧运动课吗？

17 jacks   

n.抓子游戏；千斤顶( jack的名词复数 )；（电）插孔；[电子学]插座；放弃

参考例句：

• Hydraulic jacks under the machine produce the movement. 是机器下面的液压千斤顶造成的移动。 来自《简明英汉词典》
• The front end is equipped with hydraulic jacks used for grade adjustment. 前瑞安装有液压千斤顶用来调整坡度。 来自辞典例句

18 intensity   

n.强烈，剧烈；强度；烈度

参考例句：

• I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
• The strike is growing in intensity.罢工日益加剧。