The Myth Behind Drinking 8 Glasses of Water a Day | World of Psychology

The Myth Behind Drinking 8 Glasses of Water a Day | World of Psychology

The Myth Behind Drinking 8 Glasses of Water a Day

By JAMIE HALE

It’s common knowledge that we should drink at least eight glasses of water a day. Or at least many people think it’s common knowledge.
Heinz Valtin, a Dartmouth Medical School physician, disagrees.
In an invited review published by the American Journal of Physiology, Valtin reported that there is no supporting evidence to back up the popular recommendation to drink eight 8 oz. glasses of water per day.
How did the 8 X 8 myth start? Valtin thinks that the notion may have started in 1945 when the Food and Nutrition Board of the National Research Council recommended approximately “1 milliliter of water for each calorie of food,” which would amount to roughly 2 to 2.5 quarts per day (64 to 80 ounces).
In its next sentence the board stated, “[M]ost of this quantity is contained in prepared foods.” But that last sentence seems to have been missed, so that the recommendation was erroneously interpreted as how much water a person should drink each day.

You may be surprised to find out many foods are high in water content. Below I have provided an abbreviated chart that lists the water content of some popular foods (Hale, 2007; Hale, 2010). The water percentage of each food is listed after its name.
Water Content of Foods
Apples: 85
Apricots: 85
Bean sprouts: 92
Chicken, boiled: 71
Cucumbers, raw: 96
Eggplant, raw: 92
Grapes: 82
Lettuce, head: 96
Oranges: 86
Peaches, raw: 90
Peppers, green: 94
Potatoes, raw: 85
Strawberries, raw: 90
Turkey, roasted: 62
Watermelon: 93
(The information above was referenced from Survival Acres)
Caffeinated beverages and other drinks also should be counted toward daily water intake. University of Nebraska researcher Ann Grandjean and colleagues (Grandjean, 2000) conducted a study, published in the Journal of the American College of Nutrition, about the effects of caffeinated beverages on hydration. Grandjean and her colleagues used 18 healthy male adults for their subjects.
On four separate occasions, the subjects consumed water or water plus varying combinations of beverages. The beverages were carbonated, caffeinated, caloric, and noncaloric colas and coffee. Body weight, urine, and blood evaluations were performed before and after each treatment.
Grandjean found that there were no changes in the body weight, urine, or blood evaluations for the different beverages. The study found no significant differences in the effect of various combinations of beverages on the hydration status of healthy adult males. Grandjean concluded that advising people to disregard caffeinated beverages as part of their daily fluid intake is not supported by the results of her study.
She went on to say, “[T]he purpose of the study was to find out if caffeine was dehydrating in healthy people who are drinking normal amounts. It is not.” There seems to be a large number of people who hold onto the myth that caffeine causes dehydration, probably because that’s what they have always heard.
Under some circumstances, significant fluid intake — at least eight 8-ounce glasses — is advisable: for the treatment or prevention of kidney stones, for example, as well as under special circumstances, such as performing strenuous physical activity or enduring hot weather.
However, most people currently are drinking enough water and, in some cases, more than enough. There is potential harm in drinking too much water (Hale, 2010). Water intoxication, a life-threatening condition, can occur when one drinks excessive amounts of water.
Water intoxication occurs when the kidneys are unable to excrete enough water (as urine), which leads to dilution of blood sodium. Mental confusion and death can result.
The bottom line? Drink when you are thirsty, not because you believe you need to.
References
GrandJean, AC., Reimers, KJ., Bannick, KE., Haven, MA. & Haven, MC. (2000). The effect of caffeinated, non-caffeinated, caloric and non-caloric beverages on hydration. Journal of the American College of Nutrition 19 (5):591-600.
Hale, J. (2007). Knowledge and Nonsense: The Science of Nutrition and Exercise. Winchester, KY: MaxCondition Publishing.
Hale, J. (2010). Should I Eat the Yolk? Separating Facts From Fiction To Get You Lean, Fit And Healthy. Berkeley, CA: Ulysses Press.
http://www.snopes.com/medical/myths/8glasses.asp
[accessed December 3, 2010]
http://survivalacres.com/information/water_content.html
[accessed December 3, 2010]

Jamie Hale is a science writer, exercise & nutrition consultant, outdoor enthusiast, scientific data researcher, lecturer and founder of Knowledge Summit Research Group
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» petite-productivity :mnmlist

» petite-productivity :mnmlist

mnmlist: petite-productivity

There exists in France a small company called Teddyfish that makes bags by hand.

Their philosophy of production is beautiful:

“We believe in ‘petite-production’, which means the willingness to work on slower rhythm and scale. Through creating and hand-making by ourselves, we are aiming to flavor our products with the warmth of the craftsmen’s hands, instead of the gasoline from the machine.”

Imagine if our world of mass-production was turned into a world of petite-production. People would hand-make clothing bicycles furniture food.

We would produce less and consume less. Things would cost more but people would make more for their labor.

We would love our work more. Produce quality things that last. Love our lives more. Call it Anti-Walmartization.

Slow down make less do it better be happier.

Does the GRE Measure Anything Related to Graduate School? | World of Psychology

Does the GRE Measure Anything Related to Graduate School? | World of Psychology

Does the GRE Measure Anything Related to Graduate School?

By JAMIE HALE

The Graduate Record Examination, or GRE, is required for admission to many graduate schools around the country. The computerized test includes verbal, quantitative and analytical writing sections. The test was designed to predict success in graduate school.
The research, however, does not support the idea that a high GRE score will predict graduate school success.
Sternberg & Williams (1997) conducted a study to investigate how well GRE scores predicted graduate students’ success. Forty psychology faculty members at Yale were asked to rate graduate students’ abilities on five scales: analytical, creative, practical, research and teaching. The researchers also looked at first- and second-year student’s grade point averages, and overall evaluations of dissertations made by independent, outside raters.

Sternberg & Williams found GRE scores were only modest predictors of first year grades but not second year grades. When looking further at the GRE subtests, they found only the analytical test score successfully predicted more consequential evaluations of student performance. But this was true for men only.
According to data from the Educational Testing Service (ETS), the test’s manufacturer, the GRE is a weak predictor of first year graduate school grades (Fairtest.org, 2007). A study conducted by Morrison, T. & Morrison, M. (1995) found an even weaker relationship between test scores and grades — GRE scores predicted a mere 6 percent of the variation in grades.
Many schools have minimal GRE requirements. If applicants do not meet these requirements they will not be admitted to graduate school, even if they had excellent undergraduate grades, an impressive resume and stellar recommendations.
Some colleges receive hundreds of applications each semester. It becomes a daunting task to conduct hundreds of interviews or review hundreds of applications. Many of the applicants have high grade point averages, and equally impressive letters of recommendation, thus making it practical to turn to the only other quantitative source of information — the GRE — that administrators have (Williams, 1997).
But if that quantitative source doesn’t really predict or have much of an association with what people think it does — graduate school academic performance — is it really a valid source of information to turn to?
References
Cornell Science News (1997). Study of Graduate Record Exam shows it does little to predict graduate school success.http://www.news.cornell.edu/releases/Aug97/GRE.study.ssl.html[accessed Dec. 5, 2010]
Enright, M. K. & Gitorner, D. (1989). Toward a description of successful graduate students. Princeton, NJ: Educational Testing Service.
Fairtest.org (2007). Examining the GRE: Myths, Misuses, and Alternatives [accessed Dec. 5, 2010]
Milner, M., McNeil, J. & King, S.W. (1984). The GRE: A Question of Validity in Predicting Performance in Professional Schools of Social Work. Educational and Psychological Measurement, vol. 44, pp. 945-950.
Morrison, T. & Morrison, M. (1995). A Meta-Analytic Assessment of the Predictive Validity of the Quantitative and Verbal Components of the Graduate Record Examination with Graduate Grade Point Averages Representing the Criterion of Graduate Success. Educational and Psychological Measurement, v. 55 (no. 2) pp. 309-316.
Sternberg, R. & Williams, W. (1997). Does the Graduate Record Examination Predict Meaningful Success in the Graduate Training of Psychologists? American Psychologist, v. 52 (no. 6), pp. 630-641.
Williams, W. (1997). Reliance on Test Scores Is a Conspiracy of Lethary. The Chronicle of Higher Education.

Jamie Hale is a science writer, exercise & nutrition consultant, outdoor enthusiast, scientific data researcher, lecturer and founder of Knowledge Summit Research Group
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How clean do we need to be?

I've often thought about how I grew up without showering everyday. I don't remember that being the necessity. We had to shower once every couple of days but not everyday. But now I think, why do we need to shower everyday? Of course it is nice to feel nice and fresh and not feel like a pig just because you skipped the shower in the morning because you were running late. But honestly, if you haven't been working out or profusely sweating or fell into a muddy ditch, what is the purpose of showers every day? As long as you keep yourself clean, how you do it should not matter.

We apparently use about 10 liters of water for every minute of shower. That's a huge amount of water to spend everyday to clean on dirt that isn't even there. Then there is the added cost to heat your water, plus the cost of cleaning that water in the plants for future use, plus the actual cost of getting that water to you. Not to mention water tax and the impact on the environment with all those steps. Is it really worth it?

Here is some math I will attempt to do...

water used per 10 minute long shower = 100 liters
Number of showers in a month = 30
Total water used in a month = 3000 liters

Even though it uses US information, this site tells us that each shower could cost us over $2. Considering rate differences, lets assume it costs $2.50 in Canada per shower. That is $75 per person per month! If you have a 3 person household, as in my house, it could cost $225 just to shower everyone in the house in a month! This doesn't even include your other electricity usage like washer/dryer, fridge, lights, computers.

If people reduced their number of showers from 30 a month to even 20 per month, that could lead to a $75 savings in the monthly electric bill in a 3 person household. That is a $900 saving in a year!!!!!

Can you imagine that???

So I say: Limit showers..in numbers and in duration. And hey, share if you can :) Help the environment and your wallet.

Why are some people incapable of understanding hints, no matter how unsubtle?

I grew up in a family where manners were very important and had to be followed ALL THE TIME. Consequently, I became very aware of my behaviour when I am around people. This included how I spoke to them, how I reacted to things they told me, and how I expressed my opinions, good or bad. I was taught that it is bad manners to interrupt someone when they are speaking, to tell people they are wrong unless you have a reason that explains your opinion and to put them on the spot about something they might not want to be involved with. I grew up around people who seemed to have been taught similar social rules and morals, so obviously i grew to understand that everyone is on the same page about these things. No one needs to be told to eat with their mouth closed or knock before entering someone else's room (not necessarily the case for family members) or keep your mouth shut all you have to say demeans the person you are speaking to. But it turns out not everyone has grown up with these normal social etiquettes. This is perhaps unfortunate but not surprising since there are different social rules all over the world.

What is unfortunate is when you are in a situation where someone breaks socials rules that you are used to following. How to you respond to someone who either doesn't know certain rules or just doesn't seem to care about them? It is hard for me to say something rude to someone's face. But what happens when someone else says something clearly rude to you? It is likely to bring your defensive wall up...because it is normal. But there is also the social rule that stops you from saying something rude back. So there is a conflict in your head. Do you respond to put them in their place or do you try to calm yourself and let it glaze over you? I don't have the answer to that but I would love to find out.

In my experience, even when I have tried to subtly let the person know that their actions are making me uncomfortable, they don't understand. Not sure if it is because they don't care or they just don't get the hint. So my practice has been usually to keep quite and let it move on. If it is something serious I might try to deal with it at a later time, after my defensiveness has subsided. Usually when we are defensive, we don't think clearly and are likely to react somewhat irrationally.

If anyone has interesting stories that explains their unusual situations, please feel free to share it :)