Unit 2
Section (A)
Iron and the Effects of Exercise

Sports medicine experts have observed for years that endurance athletes, particularly females,

frequently have iron deficiencies. Now a new study by a team of Purdue University researchers

suggests that even moderate exercise may lead to reduced iron in the blood of women.

"We found that women who were normally inactive and then started a program of moderate exercise

showed evidence of iron loss," says Roseanne M. Lyle, associate professor at Purdue. Her study of 62

formerly inactive women who began exercising three times a week for six months was published in the

journal Medicine & Science in Sports & Exercise.

"Women who consumed additional meat or took iron supplements were able to bounce back," she

notes. "But the new exercisers who followed their normal diet showed a decrease in iron levels."

Iron deficiency is very common among women in general, affecting one in four female teenagers and

one in five women aged 18 to 45, respectively. But the ratio is even greater among active women,

affecting up to 80 percent of female endurance athletes. This means, Lyle says, that "too many women

ignore the amount of iron they take in";. Women of child-bearing age are at greatest risk, since their

monthly bleeding is a major source of iron loss. Plus, many health-conscious women increase their risk

by rejecting red meat, which contains the most easily absorbed form of iron. And because women often

restrict their diet in an effort to control weight, they may not consume enough iron-rich food, and are

liable to experience a deficiency.

"The average woman takes in only two thirds of the recommended daily allowance for iron," notes

another expert. "For a woman who already has a poor iron status, any additional iron loss from exercise

may be enough to tip her over the edge into a more serious deficiency," notes the expert.

Exercise can result in iron loss through a variety of mechanisms. Some iron is lost in sweat, and, for

unknown reasons, intense endurance exercise is sometimes associated with bleeding of the digestive

system. Athletes in high-impact sports such as running may also lose iron through a phenomenon

where small blood vessels in the feet leak blood.

There are three stages of iron deficiency. The first and most common is having low iron reserves, a

condition that typically has no symptoms. Fatigue and poor performance may begin to appear in the

second stage of deficiency, when not enough iron is present to form the molecules of blood protein that

transport oxygen to the working muscles. In the third and final stage, people often feel weak, tired, and

out of breath — and exercise performance is severely compromised.

"People think that if they're not at the third stage, nothing is wrong, but that's not true," says John L.

Beard, who helped design the Purdue study. "You're not stage 3 until your iron reserves go to zero, and

if you wait until that point, you're in trouble."

However, most people with low iron reserves don't know they have a deficiency, because traditional

methods of calculating the amount of iron in blood (by checking levels of the blood protein that

transports oxygen) are not sufficient, Beard states. Instead, it's important to check levels of a different

compound, which indicates the amount of storage of iron in the blood. While active, child-bearing age

women are most likely to have low iron stores, he notes, "Men are not safe, especially if they don't eat

meat and have a high level of physical activity." (An estimated 15 percent of male long distance runners

have low iron stores.) Beard and other experts say it's advisable for people in these groups to have a

yearly blood test to check blood iron reserves.

If iron levels are low, talk with a physician to see if the deficiency should be corrected by modifying

your diet or by taking supplements. In general, it's better to undo the problem by adding more iron-

rich foods to the diet, because iron supplements can have serious shortcomings. Supplements may

produce a feeling of wanting to throw up, and may be poisonous in some cases. The best sources of iron,

and the only sources of the form of iron most readily absorbed by the body, are meat, chicken, and fish.

Good sources of other forms of iron include dates, beans, and some leafy green vegetables.

"Select breads and cereals with the words 'iron-added' on the label," writes sports diet expert Nancy

Clark. "This added iron supplements the small amount that naturally occurs in grains. Eat these foods

with plentiful Vitamin C (for example, drink orange juice with cereal or put a tomato on a sandwich) to

enhance the amount of iron absorbed." Clark also recommends cooking in iron pans, as food can derive

iron from the pan during the cooking process. "The iron content of tomato sauce cooked in an iron pot

for three hours showed a striking increase, the level going up nearly 30 times," she writes. And people

who are likely to have low iron should avoid drinking coffee or tea with meals, she says, since

substances in these drinks can interfere with iron being absorbed into the body.

"Active women need to be a lot more careful about their food choices," sums up Purdue's Lyle. "If

you pay attention to warning signs before iron reserves are gone, you can remedy the deficiency before

it really becomes a problem."

Words: 900

New Words

▲endurance n. 忍耐，忍耐力
　moderate a. 1.中等的，适中的，适度的 2.中庸的，温和的
　evidence n. 根据，证据，证明
　journal n. 1.日报，杂志，期刊 2.日记
　consume vt. 1.吃，喝 2.消耗，花费（尤指大量地）
　supplement n. 1.增补(物)，补充(物) 2.（杂志或报纸的）副刊，增刊
vt. 增补，补充
　bounce v. （使）弹回，（使）反弹
n. 弹，弹力
　respectively ad. 分别地，各自地
　ratio n. 比率
　plus conj. 并且，而且
prep. 加，加上
n. 1.加号，正号 2.有利因素
a. 正的
　restrict vt. 限制，约束
　liable a. 1.易于... ...的，有... ... 倾向的 2.有法律责任的，有义务的
　allowance n. 1.限额，定量 2.津贴，补助，零用钱
　digest vt. 1.消化 2.领会
　digestive a. 消化的
　phenomenon n. 现象
　vessel n. 1.血管，脉管 2.容器，器皿 3.船，舰
　typical a. 典型的，有代表性的
◆typically ad. 典型地，有代表性地
　fatigue n. 疲劳，劳累
　molecule n. 分子
　protein n. 蛋白质
　calculate vt. 1.计算，估算 2.认为，相信，推测
　sufficient a. 足够的，充分的
　compound n. 复合物，混合物
　indicate vt. 1.标示，表明 2.指示方向
　storage n. 储存，储藏
　advisable a. 可取的，适当的，明智的
　yearly a. 每年的，一年一度的
　physician n. 内科医生
　modify vt. 修改，更改，改善
　undo vt. 1.取消，消除 2.解开，松开
　shortcoming n. 缺点
　select vt. 选择，挑选
▲cereal n. 谷类作物，谷类食物（如麦片等）
　plentiful a. 大量的，丰富的
　derive v. 1.得到，获取 2.起源于
　striking a. 1.显著的，突出的，惊人的 2.（由于美貌而）引人注目的，吸引人的
　interfere vi. 1.妨碍，干扰 2.干涉，干预
　remedy vt. 补救，纠正
n. 治疗方法，解决方法



Phrases and Expressions

　lead to 导致
　bounce back 恢复正常，恢复过来
　in general 大体上；通常
　up to 至多，多达，直到
　take in 吸入，吞入
　at risk 处在危险之中
　tip over the edge 引起明显变化；(使)进入另一状态
　out of breath 呼吸急促，气喘吁吁
　add sth. to 加，增加，添加
　throw up 恶心，呕吐
　go up （价格、水平等）升高，上升
　sum up 概括，总结



Proper Names

　Purdue University 珀杜大学
　Roseanne M. Lyle 罗斯安妮·M.莱尔
　Medicine & Science in Sports & Exercise 《体育运动医学与科学》(期刊名)
　John L. Beard 约翰·L.比尔德
　Nancy Clark 南希·克拉克

Section (B)

Does Exercise Have Unexpected Benefits?

Just as exercise strengthens the heart and lungs, bones and muscles, it may also power up the brain.

A succession of scientific studies of animals implies that physical activity has a positive effect on mental

functioning.

"It's clear that the brain benefits from exercise," says brain scientist William Greenough of the

University of Illinois at Urbana-Champaign. His studies with rats have demonstrated two primary

effects of activity: vigorous physical exercise provides the brain with more fuel, and skill-based exercise

increases the formation of connections in the brain, which, according to the proposals of some scientists,

may make the brain better able to process information.

In one experiment, laboratory rats were separated into three groups. One group was exercised by

running inside an automatic wheel, a second group improved their skills in a complicated obstacle

course, and a third group was inactive.

"The animals that learned to go through the obstacle course exhibited a greater number of brain

connections than the animals in the exercised or inactive groups," Greenough said. "In contrast, the

animals that exercised inside the automatic wheel possessed a greater density of blood vessels in the

brain than did either of the other two groups of animals."

Learning a new dance step may boost the brain in the same way that learning a language can, he

says. And if the dance is a good physical exercise as well, the benefits multiply. Young brains may be

especially able to boost brain power through exercise, suggested another of Greenough's experiments

that showed the most significant changes in the brain occurred among rats that had been exercised

when very young. And while animals aren't people, he says it is logical to make the inference that an

effect found in rats may also apply to humans.

Human studies have focused primarily on older adults and suggest that regular exercise can improve

the speed with which the brain processes information. Measurements made by Arthur Kramer at the

University of Illinois demonstrated that inactive adults, aged 63 to 82, could hit buttons faster in

response to a tone after they went through a 10-week water exercise course. A corresponding control

group that didn't exercise showed no improvement.

This boost in reaction time after exercise training may occur because declines associated with getting

old could actually stem from declines in physical condition. Some scientists speculate the reduction in

mental function often attributed to getting old may really be a penalty of neglecting to stay physically

active, in addition to related factors such as medicines and poor diet.

"In older people, an exercise program appears important for brain maintenance," says Daniel M.

Landers, professor of exercise science at Arizona State University, who recently published an article

reviewing the scientific literature on activity's effect on the brain.

Numerous studies show that children who engage in regular physical activity do better in school than

their inactive classmates. But until recently, the academic edge gained by participating in sports was

thought to come from the increased self-confidence, the better mood, and the ability to concentrate

that comes from burning off steam in exercise. Now, however, some scientists have revised their way of

thinking, and point to possible physical connections.

Pierce J. Howard, another expert, says new research indicates that physical exercise increases the

amount of certain brain chemicals that stimulate growth of nerve cells. Consequently, the brains of

people who exercise may be better equipped to tackle mental challenges.

Inactivity may also have negative effects on mind and body alike. "Scientists recognize that mind is

body, and body is mind," comments Howard. The most beneficial forms of exercise, he says, engage

both.

Words: 602

New Words

　succession n. 1.一连串的事物，一系列 2.连续，接续 3.继任(权)，继承(权)
　imply vt. 暗示，暗指
　rat n. 鼠，大老鼠
　primary a. 1.首要的，基本的，主要的 2.最初的，最早的
　vigorous a. 强壮的，有力的，精力充沛的
　formation n. 1.组成，形成 2.形成物，结构 3.排列，队形
　proposal n. 1.建议，计划，方案 2.求婚
　laboratory n. 实验室
　complicated a. 复杂的，难以理解或解释的
　obstacle n. 障碍（物）
　exhibit vt. 1.显示，显出 2.陈列，展览
n. 展览品，陈列品
　possess vt. 拥有，具有
　density n. 密集；密度
　multiply v. 1.（使）增加，（使）繁殖 2.乘
　boost vt. 改善，提高，增强，推动
n. 增加；帮助；鼓舞
　logical a. 合乎逻辑的，条理分明的
　inference n. 1.推断的结果，结论 2.推论，推断，推知
　primarily ad. 首先，主要地，基本地
　measurement n. 1.测量，衡量 2.（量得的）尺寸，大小
　corresponding a. 相应的，对应的
　stem vi. 源于，由... ...造成
n. （植物、灌木或树木的）茎，干
　speculate v. 推测，推断
　reduction n. 1.减少，减低，减缩 2.减少，减低，缩小
　penalty n. 处罚，惩罚；罚金
　neglect vt. 1.忽视，忽略 2.遗忘
n. 疏忽，忽略
　maintenance n. 1.维护，保养 2.保持，维持
　academic a. 1.学术的，学院的 2.纯理论的，不切实际的
　concentrate v. 1.集中，集中精神 2.集中，聚集
　revise vt. 1.修正，修改 2.复习，温习
　cell n. 细胞
　consequently ad. 因此，所以
　equip vt. 1.使有准备 2.配备，装备
　tackle vt. 1.处理，应付 2.与... ...交涉
　alike ad. 一样地，相似地
a. 相同的，相像的
　comment v. 评论，发表意见
n. 评论，意见
　beneficial a. 有助的，有利的，有益的



Phrases and Expressions

　separate… into 将... ...分为
　obstacle course 越障训练；（喻）困难重重的事
　go through 完成，通过
　in contrast 相比之下
　apply to 适用于
　focus on 集中于
　engage (oneself) in 从事，忙于
　point to 表明；表示



Proper Names

　William Greenough 威廉·格里诺
　University of Illinois at Urbana-Champaign 伊利诺伊大学厄巴纳-尚佩恩分校
　Arthur Kramer 阿瑟·克雷默
　Daniel M. Landers 丹尼尔·M. 兰德斯
　Arizona State University 亚利桑那州立大学
　Pierce J. Howard 皮尔斯·J. 霍华德

Section(C)
Exercise for the Old

As a scientist, one of Steven Wolf's favorite questions to ask people at the end of a study is: "What

can you do now that you couldn't do before?"

One of the best answers he's ever received came from an 86-year-old man who learned the ancient

Chinese exercise form of tai chi as part of Wolf's study of how exercise can help seniors prevent falls.

"The man smiled at me, then lifted up one foot, bent over, and took off his shoe while balancing on his

other leg," recalls Wolf, a professor and researcher. "Then, still balancing on one leg, the 86-year-old

gentleman stood back up, bent over again, and put his loafer back on. What impressed me the most was

that he couldn't do this before studying tai chi."

Although many people assume that balance and movement problems are inevitable with age, an

increasing body of evidence demonstrates that exercise can help improve balance and strength in

elderly individuals and reduce their chance of falling. In Wolf's study, published in May 1996, 215

seniors aged 70 to 96 were divided into three groups. One group performed balance exercises on a

computer-controlled platform once a week, one group took a weekly tai chi class, and a control group

met for a weekly discussion. After 15 weeks, "the tai chi group did the best, and reduced the chance of

having a fall by 47 percent," Wolf said.

In addition, the tai chi group also showed significant improvement in the condition of their hearts and

quality-of-life measurements, such as a reduced fear of falling and an increased sense of control over

their lives. "Tai chi has been used in China as an exercise for older individuals for three centuries and as

a military art for 2,000 years," Wolf says. "The movements are very slow and careful and involve a

great deal of body movement and standing on a single limb. Practicing these movements is like learning

strategies you can use to avoid falling down."

Tai chi is just one form of exercise studied for its fall-preventing benefits as part of a recently

completed six-year project by the National Institute on Aging and the National Institute of Nursing

Research. More than 1,500 seniors at seven sites around the country participated in the trials. "The

studies showed that even a low level of exercise can reduce the risk of falls," notes Washington

University scientist Michael Province, whose analysis of the data on exercise and fall prevention

appeared last year in The Journal of the American Medical Association. "Exercise can help older adults

improve strength, balance, the ability to bend, and prevents them from tiring as easily. Improvements

in one area often carry over into another."

In general, "the evidence is increasing that the more older people can do in terms of exercise, the

better off they are — with two pieces of advice," says Province. First, older exercisers should be sure to

check with a doctor to make sure any new exercise program is safe and appropriate. Second, seniors

should start under the guidance of a qualified teacher to make sure they're doing exercises properly

and not doing too much, too soon — especially if they've been inactive.

"The problem is that to improve balance, you've got to challenge balance, which is always risky," says

Mary E. Tinetti of the Yale University School of Medicine, who studied 301 men and women aged 70

and older with at least one risk factor for falling, such as muscle weakness or use of certain medicines.

To reduce these seniors' risk of falling, Tinetti used multiple methods, including having an exercise

teacher go to a person's home and teach balance exercises. "The teacher wasn't necessarily there with

them every time they did the exercise," Tinetti notes.

Words: 626