Talk:Body water

Calculating total body water

isn't there any other way of calculating total body water

50 kHz would be a measurement of frequency, not current, which in this case would likely be a measurement of milliamperes —Preceding unsigned comment added by 71.203.242.111 (talk) 19:32, 11 March 2009 (UTC)

Have a look at the relevant chapter in any edition of Guyton's Textbook of Medical Physiology, and see what you think.Wotnow (talk) 13:18, 29 November 2009 (UTC)Wotnow

As a scuba instructor, I am often looking at new students and sizing up their lead "ballast" to help them become neutral underwater, given a suit of a certain thickness of buoyant Neoprene, or not (depending on water temperature). While trying to calculate BMI for myself, and remembering that I don't need lead to sink while most chubbier divers do, I wonder why not just subtract our body volume's weight in water from our weight, the difference being the lighter fats and the heavier frame. If one (like me) tends to be heavy boned, then that part of my weight should give me a lower fat% portion. Likewise with heavier tissue like muscles - for each part of bone,muscle, a part of fat is permitted, which should balance the weight w.r.t. water. I can forsee an error based on how full or empty the lungs are, maybe measure lung volume (difference full-empty) and either pick an endpoint (full or empty, easier) or midpoint (50% by volume, harder). Since we divers need to empty lungs to test buoyency, this is the simplest test given the availability of some 2m deep pool or preferably fresh water (salt water increases floatation). Maybe a bone density calculation could offer the bone aspect of the weight, but then how to tell between the muscles and the fat? Hansschulze (talk) 08:34, 7 September 2011 (UTC)

Suggestion for rephrasing in lead

Currently the first two sentences are "A significant fraction of the human body is water. This body water is distributed in different compartments in the body." I would recommend converting this to a more standard lead structure, such as:

In medicine, body water refers to all the water in the human body, whether in the tissues and fats, the blood, or the bones. Body water makes up a significant fraction of the human body by weight, estimated at X% ...

Adjust of course as necessary but I think bringing the lead more in line with the standard is a good idea. -- Antaeus Feldspar 15:31, 19 January 2007 (UTC)

I've rephrased the lead, incorporating your suggestion. More work is needed here, especially as far as the breakdown by body compartments. Kkosman (talk) 17:53, 30 January 2014 (UTC)

Rumours?

I think it would be fair to have a section regarding the rumoured numbers, as often mis-cited in media such as movies or TV shows. I've often seen statements like "we're all 90% water" or whatnot used in TV shows. One such example is the Star Trek episode The Omega Glory, in which it's stated that the human body is 96% water, which, according to this article, is pretty far off. I think a lot of people believe these kinds of numbers though. TheHYPO (talk) 19:17, 15 May 2008 (UTC)

I suspect that such exaggerations are due to a conflation between "water" and "hydrates." If we look at the composition of the human body in terms of atomic elements and calculate the proportions of hydrogen and oxygen compared to the rest (carbon, calcium, sodium and so on]]) then we have an inflated estimate of "water." But when we look at molecular composition instead of atomic elements then we'd find that much of our weight is hydrates (especially various forms of carbohydrates) and other compounds containing hydrogen and/or oxygen. JimD (talk) 01:26, 25 June 2017 (UTC)

From article

[ARE THESE PERCENTAGES BASED ON WEIGHT OR VOLUME ?!]

--moved from article as it belongs here 30, 3 August 2008 (UTC) --

Water is 1 kg / 1 liter. If someone has more fat, then they would be lighter than water. If you could figure out the fat volume, you might be able to do volume math, but it seems easier to me to consider weight. Maybe an MRI or 3D ultrasound could measure the respective volume(s)? That might be a more definitive study. Hansschulze (talk) 08:44, 7 September 2011 (UTC)

Contradictions

1. "Water makes up between 45 and 75% of body weight.
2. "In the average lean adult male around 90% of the body weight is water."
3. "Total Body Water = 60% of Body Weight"

--Derek Andrews (talk) 18:07, 15 April 2009 (UTC)

I don't know about the 90% figure, but the 60% figure fits with the statistical average we get from texts like Arthur C. Guyton's Textbook of Medical Physiology (57%) and Sheila Jackson's Anatomy & Physiology for Nurses (60%). And as illustrated by the range of dates for these publications (1976-1991), the figures are fairly uncontroversial, or they would not remain unchanged over such a long period. I don't have the relevent section for the most recent Textbook of Medical Physiology, but I'd bet it's the same.

As for the figures of 45% to 75%, that fits with Guyton, and represents the range of variation. What would be handy to obtain would be the mode, and then one would know the shape of the graph - i.e. is it right-skewed or left-skewed, or a 'bell' curve. Contrary to popular belief, nature seems to produce curves tha are skewed in one direction or the other, with some statisticians noting that bell, or 'normal' curves are often statistically forced rather than naturally derived.

As for the 90% figure, it could be one of several things. It could be straight-out wrong. Or it could be at the more extreme end of the range. Or it could be a percentage pertaining to something else, that has been extrapolated to the wrong sphere.Wotnow (talk) 13:18, 29 November 2009 (UTC)Wotnow

Article Assessment for WikiProject Anatomy

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Somebody fix this article, please

I can't read it. Thank you! —Preceding unsigned comment added by 24.236.192.96 (talk) 11:52, 21 May 2011 (UTC)

Water intoxication, hyponatremia, body water, etc

Please see Talk:Water intoxication#Water intoxication, hyponatremia, body water, etc for a collaboration suggestion. Last Lost (talk) 18:23, 6 December 2011 (UTC)

Proposed deletion of Animal Body Water

I have proposed the deletion of the Animal body water article, since I see no difference between the concept of animal body water and human body water. The discussion is here and I invite you to comment. I had attempted to delete the article through WP:PROD, but the tag got removed by an IP user without comment. I would've proposed a merge, but I didn't see anything worth salvaging from that article that wasn't already in this one. Thanks! Attaboy (talk) 06:04, 6 March 2014 (UTC)

Contradiction

In a large study of adults of all ages and both sexes, the adult human body averaged ~65% water. However, this varied substantially by age, sex, and adiposity (amount of fat in body composition). The figure for water fraction by weight in this sample was found to be 48 ±6% for females and 58 ±8% water for males.

If those figures of 48 and 58 are averages, the average of both groups together cannot be 65%.

If it means that all male values were between 50% and 66%, and female values between 42% and 54%, more than 90% of the sample had to be men (and most with a water fraction of 66%) to get an average of 65%. I can't access the referenced article, but the abstract tells me there were 458 adult males and 265 adult females, so that can't explain it either.

I also considered that 65% was the fraction by volume instead of weight, but in a source I found listing both volume fraction and absolute weight for a 70kg male, the calculated weight fraction was equal to the volume fraction.

Given the composition of the sample, and the listed values for males and females, an average of 55% seems possible, maybe the 65% is a typo? Prevalence 21:56, 14 September 2016 (UTC)

If you average the average means for males (58%) and females (48%) in the largest study, then you get the figure midway between them (53%). That's probably our best available figure for adults (however, it is heavily influenced by obesity, so perhaps it really refers best to adults in "McDonald's Land" countries). These figures from various studies are not going to completely agree with each other, for the reasons given in the following sentence of the article, which references populations, ages, sampling, and so on.

A far more serious problem is the previous statement based on some nursing text, plus a Guyton physiology text from 1976, that adult males are 70% water. This figure is right out of the ballpark, since it is about right for newborn children. I don't think Guyton ever said that. Guyton's 12th edition of the same text (which I was able to find) says 60% for human adults, and if the text is not referenced, a better source can be found. In any case, a later Guyton edition is always better than one that is 40 years old! I've tagged both entries, and think this textbook-based sentence should be deleted entirely, unless somebody finds me figures from some up-to-date texts which have their references (making them supposedly optimal tertiary sources).

There is a well-known problem in Wikipedia with medical stuff, so the effect that the textbooks lag the best meta-analyses in the literature by some years, and aren't as accurate or authoritative. College text authors can be lazy. So WP:MEDRS prefers meta-analysis papers in the literature (which are also valid tertiary MEDRS sources) to textbooks in many cases, especially when the literature is more recent. SBHarris 22:22, 8 October 2016 (UTC)

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Unit 731

Would it be worth mentioning Unit 731 somewhere, and their role in why we know the percentage of water in the body? It's horrifying, but important that people know how we learn these things. --192.161.114.4 (talk) 19:30, 1 December 2022 (UTC)