# The Hydraulics of Urination - maybe TMI? **URL:** \ **Category:** Factual Questions\ **Created:** [February 11, 2008, 5:50am UTC](https://boards.straightdope.com/t/the-hydraulics-of-urination-maybe-tmi/437129 "2008-02-11T05:50:04Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![yams](https://avatars.discourse-cdn.com/v4/letter/y/848f3c/32.png) [@yams](https://boards.straightdope.com/u/yams)\ **Post date:** [February 11, 2008, 5:50am UTC](https://boards.straightdope.com/t/the-hydraulics-of-urination-maybe-tmi/437129/1 "2008-02-11T05:50:04Z")
Please excuse if I misused “hydraulics.” It seems that for me, when I am taking a pee, the volume flow rate, as it were, of pee, is inversely proportional to how badly the pee needed to be taken. Please excuse if I misused “inversely proportional.” If I have been holding it in a really long time, and finally get to the bathroom, tear off my pants, sit down and - nothing. No great gush, but a wee little trickle, and I am left sitting there for many minutes (or so it seems) while an entire bladder-full of urine dribbles its way into the bowl. I would think that the more I have to go, the greater the pressure would be, and the faster everything would come out, but in fact the opposite seems to be the case. If I just go to the bathroom regularly (I havent been holding it in, but realize it is time to go) everything proceeds in a normal stream. Does anybody know why it does this? For what it’s worth, it has been like this ever since I can remember (no sudden change in urination habits), and I am a girl. love yams!! ---
**Author:** ![aldiboronti](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@aldiboronti](https://boards.straightdope.com/u/aldiboronti)\ **Post date:** [February 11, 2008, 6:03am UTC](https://boards.straightdope.com/t/the-hydraulics-of-urination-maybe-tmi/437129/2 "2008-02-11T06:03:25Z")
As a male, in advanced middle age, I can only lament, O where are the pisses of yesteryear? Believe me, _great gush_ is a phrase that has long been needless in my vocabulary when it comes to urination. You gals don’t know how fortunate you are! 🙂 ---
**Author:** ![Pullet](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Pullet](https://boards.straightdope.com/u/Pullet)\ **Post date:** [February 11, 2008, 6:10am UTC](https://boards.straightdope.com/t/the-hydraulics-of-urination-maybe-tmi/437129/3 "2008-02-11T06:10:32Z")
If you’ve been holding a large volume for a long time, the muscle around your bladder is past its normal levering point, so to speak. It is so stretched out that it cannot contract as forcefully or as completely as it normally does. Letting the bladder frequently get to this state before emptying it can lead to a chronic flaccid bladder that retains a certain amount of urine, increasing the chances of bladder infection. That’s the theory I’ve heard, anyhow, for pets who are compromised and have to have their bladders expressed manually. Makes sense in my head. ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [February 11, 2008, 12:02pm UTC](https://boards.straightdope.com/t/the-hydraulics-of-urination-maybe-tmi/437129/4 "2008-02-11T12:02:45Z")
When muscles are stretched past a certain point, they lose their ability to contract. Retaining a volume of urine that is too great will render the bladder unable to actively contract, and the urine flow will be produced by the abdominal positive pressure squeezing out the urine. This is an ineffcient mechanism and the urine stream is poor. For an occasional episode, it’s not a big issue and the bladder recovers its ability to contract properly. Retaining urine is a bad habit. In men, obstructions at the level of the prostate are common, worsening the problem. The condition of urinary retention can become chronic, leading to problems voiding and even affecting kidney function. ---
**Author:** ![muldoonthief](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muldoonthief/32/3188_2.png) [@muldoonthief](https://boards.straightdope.com/u/muldoonthief)\ **Post date:** [February 11, 2008, 3:06pm UTC](https://boards.straightdope.com/t/the-hydraulics-of-urination-maybe-tmi/437129/5 "2008-02-11T15:06:23Z")
BTW, your use of the terms “hydraulics” and “inversely proportional” were appropriate and correct. ---
**Author:** ![yams](https://avatars.discourse-cdn.com/v4/letter/y/848f3c/32.png) [@yams](https://boards.straightdope.com/u/yams)\ **Post date:** [February 11, 2008, 9:01pm UTC](https://boards.straightdope.com/t/the-hydraulics-of-urination-maybe-tmi/437129/6 "2008-02-11T21:01:42Z")
Interesting, interesting. Thank you for your replies. And please let it be known, I dont intentionally make it a habit to hold it in, but my bladder and my kidneys are strongly believed to be in cahoots, and kick things into high gear at inopportune times. When I am stuck on a train, or a bus, or in an exam that I cant leave - when I cant get out to go to the bathroom, inevitably I need to go really, really bad, and am thus stuck holding it in until I get to the station/finish the test/etc. It is completely unrelated to how much I have been drinking. I could cut off all liquids at noon, but once my 6pm exam rolls around, my kidneys will find something to funnel into the bladder. Psychosomatic, thy name is pee-break. My uterus is out to get me too, but that is another thread entirely. love yams!!