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It is a common belief that women need to go to the bathroom more often than men because of the smaller size of their bladders.

Is this true? Are there more factors involved?

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In general, people around here ask for a "notable source". Can you provide an article or the like which states that women need to use the bathroom more often or have a smaller size bladder? –  Sean Duggan Jul 11 at 12:16
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@SeanDuggan we only require sources AFTER a google search turns up negative, but in this case, asking for a notability source is inappropriate, because there's a ton examples out there: google.com/… –  Ebenezer Sklivvze Jul 11 at 12:50

1 Answer 1

up vote 11 down vote accepted

Anatomic bladder capacity is the maximum liquid volume that can fit inside the bladder [1]. While various sources [2, 3, 6] claim it is between 500 and 1000 ml none makes a comparison between men and women.

Functional bladder capacity is the urine volume that triggers micturition sensation [1]. And, yes, there are slight differences between men and women:

Fitzgerald, Stablein, and Brubaker (2002) evaluated voiding diaries in 300 women with differing racial and ethnic backgrounds, and reported that the median voided volume was 330 ml. Latini, Mueller, Lux, Fitzgerald, and Kreder (2004) analyzed multiple variables from voiding diaries in 284 men without bothersome lower urinary tract symptoms and found that the median voided volume was 382 ml. Van Doorn and associates (2011) evaluated voiding parameters in 1688 Dutch men and found a similar mean voided volume in adult men of 400 ml [1].

However, many factors influence this values:

Because functional bladder capacity represents the intravesical volume present when an individual makes a decision to urinate, it is prone to variability based on multiple factors, such as the magnitude of the desire to urinate and individual judgment based on considerations related to the availability of a toilet in the near future [1].

But not only these. Age also matters [4]:

All three groups reported that mean voided volumes tended to be small in older adults, although 24-hour volumes remained unchanged. Van Doorn and associates (2011) followed patients longitudinally over a period of 6.5 years and found that median voided volumes declined from 400 ml to a median value of 245 ml as men aged [1].

Overactive bladder is a condition that modifies functional bladder capacity and it is quite common amongst women:

At minimum, 11 to 16 million women in the United States cope on a daily basis with symptoms that include sudden strong urges to urinate, difficulty delaying voids, frequent trips to the bathroom, and in many cases involuntary loss of urine when urgency strikes. They may wear pads for accidents, plan ahead for access to bathrooms, and modify their social and work lives to accommodate their symptoms [5].

And there are other conditions more common in women which can make them go to the bathroom more often [7]:

  • Urinary incontinence
  • Stress incontinence
  • Neurogenic bladder
  • Flaccid bladder
  • Spastic bladder
  • Bladder stones
  • Bladder extrophy
  • Urinary retention
  • Cystitis

References:

  1. Mikel Gray. Evaluation of Bladder Filling/Storage Functions. Urol Nurs. 2011;31(3):149-153. Available on Medscape.com. Accessed 11.07.2014
  2. Wikipedia contributors, "Urinary bladder," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Urinary_bladder&oldid=612184165 (accessed July 11, 2014).
  3. WebMD. Image Collection: Human Anatomy: The Bladder http://www.webmd.com/urinary-incontinence-oab/picture-of-the-bladder (accessed 11.07.2014)
  4. Siroky MB. The aging bladder. Rev Urol. 2006;6 Suppl 1:S3-7. PubMed PMID: 16985852.
  5. Hartmann KE, McPheeters ML, Biller DH, et al. Treatment of Overactive Bladder in Women. Rockville (MD): Agency for Healthcare Research and Quality (US); 2009 Aug. (Evidence Reports/Technology Assessments, No. 187.) Chapter 1, Introduction. Available from: http://www.ncbi.nlm.nih.gov/books/NBK32536/
  6. Glenn Elert and his students. Volume of a Human Bladder. Available at http://hypertextbook.com/facts/2001/DanielShaw.shtml. Accessed 11.07.2014
  7. (reviewed by) George Krucik. Body Maps: Bladder. Available at http://www.healthline.com/human-body-maps/bladder. Accessed 11.07.2014
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Re: median "voided volume" in men & women, those are from different studies which each have vastly different numbers which are not terribly conclusive. If you have access, please follow up the reference provided in the first answer here: theguardian.com/notesandqueries/query/0,,-1820,00.html ; It might also be worth following up on the theory being aired here: oprah.com/health/… –  coleopterist Jul 11 at 13:52
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I think "pregnancy" could go on that list of "conditions more common in women which can make them go to the bathroom more often" :) –  Kip Jul 16 at 19:53

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