首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Do You Really Need to Drink Eight Cups of Water a Day? A)Drinking eight cups or two liters of water a day is longstanding advice
Do You Really Need to Drink Eight Cups of Water a Day? A)Drinking eight cups or two liters of water a day is longstanding advice
admin
2014-09-30
44
问题
Do You Really Need to Drink Eight Cups of Water a Day?
A)Drinking eight cups or two liters of water a day is longstanding advice. But is there any scientific basis for it, asks Dr. Chris van Tulleken.
B)You know those ads that remind us that even a small drop in hydration(水合作用)levels can massively affect performance so you need to keep hydra ted with whatever brand of super drink they’re selling?
C)They seem pretty scientific, don’t they? Man in white coat, athlete with electrodes attached and so on. And it’s not a hard sell because drinking feels right—you’re hot and sweating so surely replacing that fluid must be beneficial.
D)Well earlier this year sports scientists in Australia did an extraordinary experiment that had never been done before(British Journal of Sports Medicine, September 2013, Current hydration guidelines are erroneous: dehydration does not impair exercise performance in the heat, Wall BA). This group wanted to find out what happened to performance after dehydration. So they took a group of cyclists and exercised them until they lost 3% of their total body weight in sweat.
E)Then their performance was assessed after rehydration with either 1)nothing, 2)enough water to bring them back to 2% dehydration or 3)after full rehydration. So far nothing unusual, but the difference between this and almost every other study that’s ever been done on hydration was that the cyclists were blind to how much water they got. The fluid was given intravenously(通过静脉地)without them knowing the volume.
F)This is vital because we all, and especially athletes, have such an intimate psychological relationship with water consumption. Remarkably, there was no performance difference between those that were fully rehydrated and those that got nothing. This study was part of a growing movement to "drink to thirst" which hopes to persuade athletes not to over hydrate with the potentially fatal consequence of reducing your sodium level, causing hyponatraemia(低钠血症).
G)Perhaps the result shouldn’t be so surprising. Humans evolved doing intense exercise in extreme heat and dryness. We are able to tolerate losses in water relatively well whereas even slight over hydration can be far more dangerous. In simple terms, being too watery is as bad for you as being too concentrated.
H)But what about the rest of us who aren’t cycling around the desert in Western Australia? There is a very well accepted idea that we should drink about eight cups of water per day(two to three liters)in addition to our food and other drinks. We are crammed with positive messages about the healing properties of water and how it will improve everything from our brains to our bowels. And we know that without it we will die in days.
I)It’s a short leap of logic to think that if a lack of water is bad for you then hydration must be good—purifying, cleansing water washing though your organs must be beneficial, relieving internal heat or fever. It surely improves your skin, helps you think, reduces your risk of kidney stones and turns your urine a lovely light, straw/champagne color rather than the fetid orange syrup you produce at the end of a long day where you haven’t had time to drink.
J)So I’ve looked through the literature and I found a review article saying all of this and more. It was written by a group of respected physicians from American and French hospitals and it clearly supported the widely held belief that you should drink two to three liters of water a day. It said that people with a high urine output have a lower rate of kidney stone disease, that the flushing action of the water may reduce the risk of a urinary tract infection(especially in women after sex). Perhaps most importantly, they referenced a surprising study which showed that paradoxically an increased intake of water increased the risk of bladder cancer. But only tap water. And there’s the clue.
K)A footnote at the end of the article explained that what you thought was a scientific article in a scientific journal is in fact a supplement, sponsored by a major mineral water manufacturer. All of the authors received reward from this company, which also provided medical writing assistance. So this isn’t research, but it’s marketing.
L)And this is one of the reasons we’re even discussing this—because increasingly drinking water doesn’t just come out of our taps for free. It’s sold to us by the same clever people that sell us yoghurts with bacteria in them that probably don’t do us much good, something I look at separately in the television series I’ve been making. And these companies pretty consistently recommend two to three liters of water per day.
M)So where did that number come from and is there any reason to think it correct? Well the grain of truth is this—people in temperate climates who are not doing sustained physical exercise do need around six to eight cups per day but that can be contained in food, alcohol or caffeinated beverages. Yes, beer and coffee do not dehydrate you to any noticeable extent(there’s a nice paper where some medical students got to drink quite a lot of beer and had their urine studied—British Medical Journal(Clin Res Ed), December 1982, Acute biochemical responses to moderate beer drinking, Gill GV).
N)There is no evidence that adding the eight cups of water to everything else you drink will do you any good and it could do you harm(American Journal of Physiology—Regulatory, Integrative and Comparative Physiology, November 2002, Drink at least eight glasses of water a day. Really? Is there scientific evidence for "8x8"? Valtin H). But the great thing is that just like a top-level athlete you don’t need to worry about exactly what that total daily requirement is because your body will sort it all out for you. If you drink too much you pee it out. If you drink too little you get thirsty and pee less. It’s all exquisitely well-controlled in the same way that your intake of oxygen is well-controlled.
O)Saying that you should drink more water than your body asks for is like saying that you should consciously breathe more often than you feel like because if a little oxygen is good for you then more must be better. Like most things in life there’s a Goldilocks amount—not too little and not too much. There is only one "just right".
You don’t need to be too much concerned about how much you should drink a day because your body can work it out for you.
选项
答案
N
解析
同义转述题。定位句提到,你没必要担心日常需水量具体是多少,因为你的身体会为你理清这件事情。题干中的be too much concerned about和work it out分别是对定位句中的worry about和sort it all out的同义转述,故N)为答案。
转载请注明原文地址:https://kaotiyun.com/show/Nmm7777K
0
大学英语六级
相关试题推荐
Thecentralnotionofsociallearningtheoriesisthatpeoplelearnattitudes,beliefs,andbehaviorsthroughsocialinteraction
A、Promiselong-termcooperationwiththeCompany.B、Explainfranklytheirowncurrentfinancialsituation.C、Payfortheprintin
Tounderstandwhyweshouldbeconcernedabouthowyoungpeopleread,ithelpstoknowsomethingaboutthewaytheabilitytore
A、Avoidthedifficultpartinthejob.B、Askthecompanyforhelp.C、Learnhardbyworkingextrahours.D、Findamoreexperience
A、Makingaprofitisthemostimportant.B、Acompanyshouldgiveitsstaffpressure.C、Thecustomerisalwaysright.D、Theirpro
A、Coffeeistooexpensivefortheman.B、Thesupermarketisgoingtomoveaway.C、Themanprobablylikesdrinkingcoffee.D、The
Ifyou’rehappyandyouknowit,maybeyoureallyshouldclapyourhands.That’sbecausebeinghappymightmakeyoulivelonger.
Ifyou’rehappyandyouknowit,maybeyoureallyshouldclapyourhands.That’sbecausebeinghappymightmakeyoulivelonger.
随机试题
如果承包人要求延期开工,应当由( )批准。
拒绝公证适用的法定情形。
简述公民和人民的区别。
下列结算方式中,()可用于异地结算。
甲公司拥有流动资产100万元,其中永久性流动资产为30万元,长期融资400万元,短期融资50万元,则以下关于该公司的说法正确的是()。
下列各项属于设备运杂费的有()。
以下有关确定会计分录和其他调整测试总体的说法中,错误的是()。
战国时期医学家华佗应用砭刺、针灸、按摩、汤液、热熨等法治疗疾病,被尊为“医祖”。()
下列选项中,属于形成权的民事权利是()。
WhenaScottishresearchteamstartledtheworldbyrevealing3monthsagothatithadclonedanadultsheep,PresidentClinton
最新回复
(
0
)