The Biology of Holding Pee - Male-Female Differences

[Calloway]

Hello

Regarding the previous posts about differences between males and females on holding pee. Those who expressed the opinion that the differences are due to habit not sex are generally wrong. There are real, rather significant differences in the "biological machiney" that men and women use to hold their pee.

I researched this out seveal years ago and I thought I posted it on this fourm once maybe not -- in any case here is my "disscertation" (LOL) on the biological differences between the sexes as regards holding pee.

*****************Biology of Holding Pee by Doc Calloway************
last updated April, 2003

This forum has had numerous discussions about holding urine and many on this forum practice holding their urine. The question of who can hold it the longest men or women as often been discussed. Many people give examples from their own lives but this may or may not reflect the real world of the average person. Since I am a biological scientist (biochemist/ecologist) I spent some time reviewing the urology literature and so here are some medical facts about the “biology of holding urine”.

I know urine holding is a fantasy and is erotic for some people – if you think cold scientific facts will “ruin it for you” then please do not read this post.

First there are two factors that determine how MUCH urine you can hold:

1) Your bladder size and,
2) The power of your tensor muscles in your urethra.

If you are also considering how LONG you can hold it there is another factor:
3) That is how fast your kidneys make urine.

First, on bladder size:

We have heard arguments on this but the facts are that bladder size like all other internal organs (e.g., liver, spleen, kidneys, heart, blood volume etc) can be described by allometry. This means that, on average, there is a constant relationship between your body weight and your bladder size. Big people will tend to have big bladders and small people small bladders. OF COURSE there will be exceptions! (also this would be your “normal” body weight – an overweight person is not a large person in this context).

But a big person with a big bladder does not have any clear “advantage” over a small person with a small bladder. Why? Because a big person will probably also have large kidneys and more blood volume to purify so the big person will make more urine faster than the small person.

So on average men are larger than women so, on average they probably larger bladders so they can probably hold MORE urine – again on average. (obviously there are women in the world who can hold a lot or urine).

Second, what about urethral closing (holding) power?:

Well here males have a huge advantage. It all boils down to three factors these are plumbing, plumbing and plumbing!

The female urethra is about 3 – 4 cm long and the female urethral muscle is about 3 cm in length. In contrast, the male urethra is about 20 – 25 cm long and the male urethral muscle mass controlling his sphincter is over 6 cm long. It is just a much more powerful muscle system in males.

But the male advantage does not end there. The urethral sphincter muscles in females are located only on the sides or the urethra in females. In males the sphincter muscle totally surrounds the urethra and can totally clamp off the tube.

The sphincter on males in much more efficient. Because the treatment of urinary incontinence is a big medical business many tools and instruments have been developed in urology and are use in the science of urodynamics.

Small devices called micropiezometers and these can be inserted into the urethra to measure pressure generated when the patient “clamps down”. On average females can exert a pressure equal to about 60 cm-water – while the average for a male urethra is 85 cm-water. This means with the bladder pressure in the average women reaches 60 cm-water she will lose urine involuntarily while the average man would still be able to “hold it”. Of course there is biological variability but while it is rare for a female to be able to generate pressures as high as 100 cm-water while some males can clamp down with a pressure of 185 cm-water.

In the question an answer session of an incontinence conference a noted European urologist made the comment that a male should be able to contain a full bladder about twice as long as a female due to this fact.

In fact some interesting things have happened as a result of this difference. In the 1980’s when the United States military started letting women into combat positions a strange thing happened. About 15 – 20 % of the women who entered the airborne training experienced involuntary urine loss when they landed from a parachute jump. These women were young (18 – 23 years old), never pregnant and in excellent physical condition. The problem had never been seen in male paratroopers. Likewise 20 - 30% of female college-age atheletes in stress sports like basketball and volley ball have urine leakage problems when under stress. The clamp for holding pee is just not as efficient in females.

The stronger uertheral sphincter is common in other mammalian species also -- e.g., dogs. Nature has not chosen to give males biological advantanges in most areas (age, disease etc.) but this is one are where males are the stronger sex.

In fact, the weakness of the urethra is a major factor behind a large percentage of female incontinence problems. So there you have it this should stimulate some interesting discussion. If anyone is skeptical I can direct you to places where you can read this for yourself.

There is a biological reason for the powerful male urethral sphincter. During sex the male urethra must do double duty – keeping urine out of the semen and keeping semen from back washing into the bladder. Ejaculations are under tremendous pressure so the male urethra needs to be very powerful. In the female the urethra only has one function – holding urine.

So all for a male and female with equal bladder size the man should be able to hold for a larger volume because he can control a higher pressure. However, some of this advantage could be lost if the male produces urine at a faster rate because he would fill faster.

Summary, a male should be able (on average to hold more urine) but how long the urine could be held might be closer and also depend on the rate the two people make urine.

There is a short summary of this information here: http://en.wikipedia.org/wiki/Urethral_sphincter

Cheers Doc Calloway

[Adrian]

Interesting. However I think it's probably a good idea to avoid going down the route of generalisations, particularly since there is no such thing as an 'average' person. I think habit and evolution do play a part in things as well. I think there is certainly more a 'tradition' of women go to pee on a precautionary basis than men doing it because historically they've had fewer natural toilet opportunities than men and clothing plus physiological differences have meant that it's a more complex procedure than for men. They can't just 'whip it out' at a second's notice.

Your perfectly valid biological points to one side, it's not difficult to see how the assumption often gets made that women have weaker bladders than men. However I've known women who can last practically all day without going to the toilet and I've also known men, who like myself, often have to go at fairly frequent intervals. I'm sorry to pour cold water on your theory but I don't think the physiological differences advantage wise are significant enough for a conclusion to be drawn that men have an incontrovertible advantage over women. I think at the end of the day there are people who can hold well for long periods and people who can't and sex has actually very little to do with it.

What I think is significant however is aqe. Women are likelier to experience the effects of weakening of the pelvic floor from middle age onwards, resulting in continence problems and a more frequent need to pee. Kegel exercises are good for helping to correct some of these problems. Men are likelier to experience prostate problems from middle age onwards which again can lead to continence difficulties. Those problems too can often easily be treated with surgery and drugs and/or implants so long as they're diagnosed correctly and at an early staqe.

Perhaps what's most important is that so far as possible people are enabled to live life to the full, whether they have continence problems or not> As in other areas of health care I would like to see more money, resources and expertise put into the field of continence management than is currently the case.

[marcelle]

Cheer up you all,the issue does not deserve all this nervousness,what ever the real facts are,this is somewhat out of the scope of our interest.What interests us most is the act of wetting after failed attempts to hold on,the warmness of pee running in our clothes and down our legs,the pee scent of our legs after we pee ourselves.Let us concentrate on issues that are not a battle field of scientific debate..In my opinion,holding capacity in men and women must be left to proffesionals only to say their last word.We can concentrate on social issues that make a woman more likely to wet herself than a man does,these may include
1.lack of sufficient puplic toilets for women and if present,they are usually crowded,long ques are the natural finding in many nations.
2.a woman usually squat to pee and must take her knickers off while a man can simply gets his cock out and pee while standing.This makes most women prefer to pee themselves than squat and take knickers off except in the toilet or a completely secluded place.

[Calloway]

Adrain,

You have made some comments here thanks.

But you are missing my point. You want to believe that women can hold their pee for long periods because it is erotic to you I suscept -- I have no problem with that -- but then perhaps you would not want to deleve into the medical facts as they will not support you ideas. Again, I find holding pee erotic too so I am not taking issue with you. But like I said you are missing the issue here.

This is not "my opinion" or "my theory" rather I presented medical facts that are available for anyone who wants to look them up like I did. My information came from medical journals only.

Any urologist will tell you the same thing. Point blank and without any doubt I assure you that it is probably physically impossible for the average woman to create bladder pressures equal to that of the average man. Period. It is a fact and these pressures have been measured in urology labs. It is not a mystery it is science. It is all because of the biophysical arrangements.

You say that "...[you have] ... known women who can last practically all day without going to the toilet and I've also known men, who like myself, often have to go at fairly frequent intervals. "

That is fine but that is merely anectodal -- sure anyone can go all day if they do not drink a lot of water. That means nothing vis a vis this discussion.

I can hold (have held) my urine for 28 hours -- with slightly curtailed water consumption. This is because I have a strong (male) urethrel sphincter and a very large bladder (I can easily hold over 1.5 L and I have gone beyond that a few times)

"I'm sorry to pour cold water on your theory but I don't think the physiological differences advantage wise are significant enough for a conclusion to be drawn that men have an incontrovertible advantage over women."

Like I noted it is not a "theory". It is medical facts that you can look up yourself if you have the interest. The physiological differences are huge in this regard.


"I think at the end of the day there are people who can hold well for long periods and people who can't and sex has actually very little to do with it."

I understand your thought -- but you are totally wrong about that. Sorry to be so blunt -- collect some medical facts to dispute me please.


"As in other areas of health care I would like to see more money, resources and expertise put into the field of continence management than is currently the case."

I agree with you here. But in the USA, at least,urinary incontinence is a big medical business and a LOT of money is already being spent -- hence all the need drugs, surgical procedures, and devices. Hence also that is why we know about bladder pressures in men and women.

Doc Calley

[Lloyd]

Doc,

The world abounds with people who would prefer to believe things that aren't supported by the facts. I learnt long ago (from conversations like this one, in fact) that there is no way you can get through to them because they are almost talking a different language from you. It doesn't make them "wrong", just disinterested in what you know because it doesn't fit what they believe. That's fine, there are plenty of people out there that think opinions are the only thing that matters, not facts, which is why there will always be an uneasy truce between scientists and others who can't or won't follow the scientific process behind something for whatever reason. These people are often the ones who will tell you that what you are saying is just a theory, completely missing the point that everything is by definition a theory (including what they are themselves saying), which holds until disproved by real facts.

I used to get quite worked up over people who either didn't seem interested in what I had to tell them, or outright contradicted me. Now I just recognise that there are always going to be people who argue the point, for whatever reason. You just have to accept that and move onto more fruitful pursuits. I found your accounts quite enlightening, because I am, like you, interested in the reasons behind things. One of these is of course the fact that women don't seem capable of holding, in general, as long as men, and there are some interesting reasons why this is possibly exacerbated by social conditioning (frequent toilet visits for whatever reason, which results in detraining what holding capacity the girl has). It was very interesting to me to read that there is a real physiological reason for this also. Everyone knows that a girl's muscles down there must be arranged differently for obvious reasons, and your post confirms this for me. Thanks for your very enlightening discussion. I appreciate it, and I'm sure there are others here who do, also.

Cheers,
Lloyd.

[Calloway]

Hi Lloyd,

Thanks for the comments and kind thoughts. Yes to be sure it was not my intention to cause any hard feelings or to upset anyone. I just thought I reveal to those who wanted to know what the medical literature says on the subject.

I am a professional biologist (Ph D-version) --but I also find, like most on this forum, that peeing is erotic. So I did what comes "natural" to me I reviewed the scientific literature. And yes like you I rely on science and I use it to learn the truth about the this matter. That said noone has to accept my findings or to believe the findings of science in this area or any other.

It is obvious to most that there are many profound differences in the anatomy and physiology of male and female mammals in general and primates in particular.

If I had said that "men have greater upper body strength than females" I doubt that Adrian would have said that he did not believe that “sex had anything to do with it”.

Likewise, anatomically one of the biggest areas of difference between men and women is their urogenital systems. Evolution produced the anatomy of our urogenital systems – and they are profoundly different between the sexes.

To wit: penis, prostate, testicals, long-double-duty-urethra in the male versus vulva, vagina, uterus, ovaries, and short-necked-single- purpose-urethra in the female. To state that these anatomical differences per se are not due to sex alone would be laughable. Yes, they are due to sex -- they are due ONLY to sex. Further, they are totally different systems.

Therefore, in my opinion, to argue that sex has nothing to do with the FUNCTION these totally different anatomical systems and that there can be no difference in their efficiency of function is illogical to me.

Medical science has found differences in how men and women are set up to hold their pee. I just revealed what science has found. I am not carrying a “torch for male superiority".

This is about biology not politics. The former is my trade -- the latter I tolerate.

Had I said that "women live longer then men" – it would not be anti-male – it is just another medical fact.

Doc Calley

[Adrian]

Calloway. Thanks for your reply. I can't help wondering who's misunderstanding who though!

Of course I find the idea of women holding for long periods of time (and not going when they should) erotic. Is there anyone here who doesn't. I doubt it.

What I was trying to say is that the biological 'facts' you've presented make out a theoretical case for men have a significantly superior holding capability. However personal experience inclines me towards the view that reality it is very different and there is little to choose between the sexes on this one. As has already been pointed out, women are likelier than men on the whole to pay precationary visits to the toilet (i.e. before a car journey) because they have fewer options and have to pull their pants down whichever number they're doing. A guy who just wants to do #1 only has to find a hedgerow and unzip. Also I know perfectly well that there are differences in plumbing, anatamoy and upper body strength between men and women, something which I hope you'll aqppreciate!

Saying that men can holder longer or better than women because of differences in bladder size and urethra length is rather like saying that men with large penises (but who aren't particularly large in other ways) are able to hold their pee longer than men with small penises. I'm sure if you made appropriate enquiries, guys with big cocks would tell you that it wasn't necessarily so.

I think the only satisfactory way of establishing whether a significant holding difference existed between men and women would be to get 50 volunteers (25 men and 25 women) and get them to spend a fortnight in a camp where their fluid intake was carefully controlled and the frequency with which each person peed as well as the quantity they passed was strictly monitored.

With regard to investment in urology care and products it may well be big business in the US where healthcare is all in the private sector. In the UK we have something called the National Health Service (NHS) and, like Punch's curate's egg, it's good in parts. Different specialities have to compete often for limited funding and I don't think urology is exactly over funded at the minute. Much more money could be put into it than is.

[Calloway]

Hi Adrian,

Thanks again for the comments -- I really think are you and I are kind of talking in different relms actually. Just a couple of comments on your comments. I am willing to continue this discussion but -- perhaps we should just agree that we see things from a different perspective?


You state that: "Saying that men can holder longer or better than women because of differences in bladder size and urethra length is rather like saying that men with large penises (but who aren't particularly large in other ways) are able to hold their pee longer than men with small penises. I'm sure if you made appropriate enquiries, guys with big cocks would tell you that it wasn't necessarily so.

My answer: No it is not -- of course not. That analogy you are making is false and non-scientific. The size of a penis has NOTHING to do with holding pee -- the strength of a urethral sphincter on the other hand has EVERYTHING to do with it. That is a kind of a canard really.

The urethral sphincter on average is much stronger in males. That has been scientifically measured on thousand of men and women. It is rare for a female to top 60 cm-water of pressure it is routine for a men to make 100 cm-water pressure -- many men can exceed that by a margin. It is not a matter of opinion.

(by your analogy women could not hold pee at all having NO penis -- SMILE)

Secondly you state: "I think the only satisfactory way of establishing whether a significant holding difference existed between men and women would be to get 50 volunteers (25 men and 25 women) and get them to spend a fortnight in a camp where their fluid intake was carefully controlled and the frequency with which each person peed as well as the quantity they passed was strictly monitored."

My comment: Here I agree with you and this study has been done actually on hundreds or young male and females! But I donot know how to get that actual raw data -- though I have tried several avenues.

In the late 1960's when civil rights groups were insisting that females be allowed in to combat positions (equal "opportunity") -- the US militiary did many "tests" to prove they should not be forced to allow women in combat.

Many points were raised in public on this matter -- e.g., upper body strength, endurance etc. -- but some were not -- one aspect of the study that was not was publically voiced -- per se -- but was mentioned in a Congressional hearing on the matter was the results of a study showing that women have less control over their bladder than men. The study was politely referred to as the special personal "bodily function needs" of women versus men. The military claimed the the reduced ability of females to "put off" voiding would be a liablilty under field combat conditions.

By the way this issue of the urethal sphincter control is not restricted to humans -- the same thing occurs with female chimps and babboons. When attacked suddenly and unexpectely female chimps often lose their pee in attempting to escape. Less control.

Cheers,

Doc Calley

[Sarah]

All,

A few further thoughts. There is, as far as I can tell, very little realistic assessment of maximum bladder capacity in medical literature. Most documents dismiss bladder capacity as 300-500ml. Whilst at university, I was involved in a determination of max capacity. Basically, filling at a constant rate (constant drinking rate), people were asked to select statements from a list as to the feeling, social considerations (when would you leave a cinema etc) and measurements of physical swelling were taken. Finally, after lots of persuasion to hold a bit longer, they peed into a measuring jug. The sample size was relatively small (22 female, 23 male) but the results were interesting. From memory (I still have the report somewhere...my boyfriend's (at the time) 1st year human biology), here are a few findings.

Average male maximum c1500ml
Average female maximum c1350ml

Of interest, the 3 largest bladders were female! 2800ml, 2200ml and 1900ml (me). There were also several females in the 600-900ml bracket, but males had less varience, generally 1000-1600. The closest parameter to relate capacity to was pelvic circumference (logical really!). The 3 large bladdered girls were aged 16-20 and we were all keen horse riders, good runners and outdoor type people (quite used to ignoring a fairly full bladder for a long time). In fact, the 2200ml girl had a "party trick" whereby she would choose a bloke to chat up and watch him start looking uncomfortable as they got through several beers, then as he made a move to go to the loo, she made her move and dragged him outside for some "fun" (oh student snogs....). She has never wet herself....I know of 2 of the blokes who did!

That said, all that Doc says seems correct - he's a learned man!. The 3 large bladdered girls here were unusual. I can still hold 1800ml btw!

Sarah

[Calloway]

Hi Sarah,

Oh my you have some most interesting comments indeed.

I've never heard the term of "average maximums" but if you mean the average volume of the largest recorded members of either sex, i.e.,
male maximum about 1500ml and female maximum about 1350ml then I would think that is pretty close to what I would suspect. These would be exceptional individuals but certainly possible to imagine.

The university study you refer to is also VERY interesting because you are the second person I have heard to mention it. Another women made reference to it several years ago on another pee-forum but I was unable to find out from her where it was done. Sounds like you were part of it!!! I realize you might not want to reveal its location as you might be revealing personal information -- but should you decide to be willing to enlighten me more on this study please do so at (doccalley@yahoo.com).

Yes I agree it is indeed suprising to find three such large bladdered persons (regardless of sex) in one study. According to the US medical literature a "large" bladder (sex independent) is considered to be any bladder of a capacity greater that 650 mL and "small" is any bladder less than 350 mL.

I rather suspect that most persons with the "normal-large" bladders (>650 ml) could probably streach it a bit. But I also rather suspect that most individuals can not put off voiding much beyond 800 mL without a bit to dampness in their underwear! LOL.

Over the years I have corresponded with many people of both sexes -- more with women - about bladder capacity. The largest volume that any woman has claimed to me was an American women who claimed to be able to hold 1.5 L.

I have no reason to doubt her as her description sounded very real. She was from family with large bladders and she had a brother who could hold over 2 L of urine. She agreed with my assessment that her disadvantage as compared to her brother was her ability to hold back the flow (i.e., her sphincter). When she and her bother tried to hold their pee in a contest she would get to a certain point and then be unable to keep from leaking spurts of pee -- even though she could stand the pain of the filling bladder she could not stop the flow.

In the case of her brother he would eventually give up because of the pain from the bladder pressure not because he lost urine. It is the same for me. I can readily force my bladder beyond 1.5 L of urine but long before I start to actually leak pee the pain becomes too much and I give up. I have never been able to force myself to the point of loss of control -- bladder pressure pain is the limit for me.

And thank for your kind words. I would certainly be "over the moon" to watch you pee out 1.8 L! What a delightful thought!!

OOOOO I just had an erotic thought about it! I imagine that I am having a pee holding contest with you on my back porch -- it is a warm spring night -- we both are holding our bladders while we keep drinking down beers by the pint -- after hours of this you start to pee dance and I am sure that I will win -- butn no you keep on squeezing and dancing and holding on and on and on --then suddenly it all ends with ME losing control and peeing unstoppable in my pants -- my face red with shame and frustration -- all lthe while you cross you legs tightly (your short skirt barely covering your panties) can continue your pee dance holding back it all back in your huge female bladder. Finally you lift your skirt to show me your dry cotton panties and then pronounce "OK , now that I have totally beaten you little man here goes!" Then you proceed to unlease a hugh gush in a thick stream of nearly 2 L of pee onto the floor around me. I get chills thinking about it!

Doc Calley