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Bladder Size Index - what's yours?


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Measured volume isn't a very fair way to compare bladder size or holding ability since larger people will naturally tend to have larger bladders. You need a measure that reflects how big someone is. I

At 5'8 and capacity of 1.7 litres takes me to a 43 - if I was a shortie I'd be into the 50s >.< x

My personal record is around 1600 ml & I'm 5ft tall so that makes me a 56 apparently. The radiographer doing the scan mentioned on my large bladder during my last pregnancy when I had to go &amp

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  • 3 weeks later...

My best hold was 1.1 litres, and I was nearly going frantic, legs crossed and holding myself.  This makes me a 23.

I might have held more on a coach journey after drinking too much beer, but the pee was by the road and not measured, as have been other long and desperate pees.  I used to estimate a pee rate of 1 pint per minute, but in vry desperate situations I have basted out pee at much more than that.

Anyone else got estimations of peeing rate?

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Hi everyone. After lurking for quite awhile, I finally decided to measure my volume and make an account.

Unfortunetly, I only have a BSI of 17 (700ml and 5'10").

I also decided to compile all the BSI values on this forum to create an updated histogram and take statistics.

In addition to the attached image, this forum has an Average BSI of 31.1375, a Median of 30, and an Sample Standard Deviation of 13.4369. 

You guys can see my work or update the chart here.

BSI Histogram.png

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On 14/01/2018 at 2:41 PM, CECA said:

Hi everyone. After lurking for quite awhile, I finally decided to measure my volume and make an account.

Unfortunetly, I only have a BSI of 17 (700ml and 5'10").

I also decided to compile all the BSI values on this forum to create an updated histogram and take statistics.

In addition to the attached image, this forum has an Average BSI of 31.1375, a Median of 30, and an Sample Standard Deviation of 13.4369. 

You guys can see my work or update the chart here.

BSI Histogram.png

Very interesting input CECA. I made a similar histogram myself back in the early days of this thread but there were fewer results back then. I was considering doing it again and separating male and female results. I did have a go at this a while back and the result were consistent with there being no difference gender wise. Small sample though.

I'd be interested to hear your opinions on the formula used if you're interested CECA.

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14 hours ago, Racehorse said:

I'd be interested to hear your opinions on the formula used if you're interested CECA.

Sure thing.

I think the best way to look at it is by solving for volume and making BSI a constant. (Also, sorry, but I had to use inches to really wrap my head around it)

Volume [ml] = 10*BSI*(Height [Inches]*2.54/100)^2.5

 

I've attached images of this graph.

f1(x) is the volume equation

f2(x) is the difference in in volume from the height x to x+4 in.

f3(x) is the percent difference between height x and x+4

O is the difference in height and B is the BSI

 

I think that the current exponent of 2.5 gives short people a pretty big advantage over tall people. Someone who's 5'10" has to hold an additional 179 mL over someone 4 inches shorter to score the same BSI. That's a percent difference of 16%. I don't really think that that difference in height would result in that much of an increase in size.

I thought that an exponent of 1.3 was a bit better, having a percent difference of 8-7% between 66 and 74 inches, but it's really arbitrary. I couldn't find any data on height vs bladder capacity, but the best would be to find an accurate trend curve on a scatterplot of volume vs. height, then model the exponent after that. We could gather the data from this forum as a lot of people also left their volume and height. 

Alternatively, a better scale might include waist circumference. The square of waist circumference is pretty close to proportional to the area (modeled after a circle, although waist is closer to an oval or an ellipse), and multiplied by height should be proportional to about the amount of space in the abdomen. The ratio of the held volume to the volume of the abdomen would be a pretty good measure of how much holding ability one has, so the formula would be BSI=Volume/(Waist circumference^2*Height). The only trouble is that is would be quite unfair for people with a large amount of fat around the waist. Also, it would be pretty difficult to measure all those. 

I don't think there's any need to rework it though. Maybe I'm wrong. Maybe 2.5 is an accurate exponent. 

I've also updated my histogram. I would like to see more data, so if anyone sees this and is hesitant to pee into a measuring cup, I recommend using an accurate scale and weighing before and after. The density of water is 1g/ml.

Graph 1.png

Graph 2.png

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So, I'm just throwing this out there, but I'm interested in using the BSI multiplied by the time of a hold for contest purposes. Two people having a holding contest strictly competing in terms of volume could use BSI to fairly compare their results. Taking that a step further, they could multiply their BSI score for that hold by the number of minutes they held (this would be so much easier if hours and minutes were in decimal instead of base 60 -_- )
For example, player 1 scores a BSI of 30 after holding for 5 hours (300 minutes) scores a total of 9000 (BSIM units maybe?) 
Perhaps player 2 only scores a BSI of 27, but is able to hold for 6 hours (360 minutes) and scores a total of 9720.
I see this as a way of giving a holder credit not only for the size of their bladder, or only for their endurance, but a combination of the two.
Thoughts?

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On 22/01/2018 at 3:25 AM, CECA said:

Sure thing.

I think the best way to look at it is by solving for volume and making BSI a constant. (Also, sorry, but I had to use inches to really wrap my head around it)

Volume [ml] = 10*BSI*(Height [Inches]*2.54/100)^2.5

 

I've attached images of this graph.

f1(x) is the volume equation

f2(x) is the difference in in volume from the height x to x+4 in.

f3(x) is the percent difference between height x and x+4

O is the difference in height and B is the BSI

 

I think that the current exponent of 2.5 gives short people a pretty big advantage over tall people. Someone who's 5'10" has to hold an additional 179 mL over someone 4 inches shorter to score the same BSI. That's a percent difference of 16%. I don't really think that that difference in height would result in that much of an increase in size.

I thought that an exponent of 1.3 was a bit better, having a percent difference of 8-7% between 66 and 74 inches, but it's really arbitrary. I couldn't find any data on height vs bladder capacity, but the best would be to find an accurate trend curve on a scatterplot of volume vs. height, then model the exponent after that. We could gather the data from this forum as a lot of people also left their volume and height. 

Alternatively, a better scale might include waist circumference. The square of waist circumference is pretty close to proportional to the area (modeled after a circle, although waist is closer to an oval or an ellipse), and multiplied by height should be proportional to about the amount of space in the abdomen. The ratio of the held volume to the volume of the abdomen would be a pretty good measure of how much holding ability one has, so the formula would be BSI=Volume/(Waist circumference^2*Height). The only trouble is that is would be quite unfair for people with a large amount of fat around the waist. Also, it would be pretty difficult to measure all those. 

I don't think there's any need to rework it though. Maybe I'm wrong. Maybe 2.5 is an accurate exponent. 

I've also updated my histogram. I would like to see more data, so if anyone sees this and is hesitant to pee into a measuring cup, I recommend using an accurate scale and weighing before and after. The density of water is 1g/ml.

Graph 1.png

Graph 2.png

You raise a good point regarding the exponent 2.5 and I thought about this quite a bit when I devised the scale. As you say, it's this exponent which affects how tall and short people are relatively favoured. 

If one makes the false, but not wildly so, assumption that the bladder is spherical then the exponent should be 3. If someone is a certain fraction taller then one can assume that all dimensions of the body are proportionally larger and the volume of the spherical bladder increases as the cube of its radius. The BMI scale, which gave me the idea for this, uses an exponent of 2 as this seems to fit the way the body scales although this value has been criticised and the value 2.5 proposed. http://www.telegraph.co.uk/news/health/news/9816596/Interactive-calculator-do-you-win-or-lose-with-the-new-BMI.html

I went with the 2.5 value as it felt about right. In reality people are all different shapes and pelvic width is of course a huge factor. Also, the male and female bladders are known to be different shapes with the female being wider laterally and more compact vertically.

It's not simple that's for sure

 

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On 1/26/2018 at 10:08 AM, Racehorse said:

If one makes the false, but not wildly so, assumption that the bladder is spherical then the exponent should be 3. If someone is a certain fraction taller then one can assume that all dimensions of the body are proportionally larger and the volume of the spherical bladder increases as the cube of its radius. The BMI scale, which gave me the idea for this, uses an exponent of 2 as this seems to fit the way the body scales although this value has been criticised and the value 2.5 proposed. http://www.telegraph.co.uk/news/health/news/9816596/Interactive-calculator-do-you-win-or-lose-with-the-new-BMI.html

Very nice. I suppose you do have that to back up the 2.5 exponent, and I guess I can kind of see waist area being proportional to height to the 1.5th power

 

On 1/21/2018 at 11:14 PM, kenn said:

So, I'm just throwing this out there, but I'm interested in using the BSI multiplied by the time of a hold for contest purposes. Two people having a holding contest strictly competing in terms of volume could use BSI to fairly compare their results. Taking that a step further, they could multiply their BSI score for that hold by the number of minutes they held (this would be so much easier if hours and minutes were in decimal instead of base 60 -_- )
For example, player 1 scores a BSI of 30 after holding for 5 hours (300 minutes) scores a total of 9000 (BSIM units maybe?) 
Perhaps player 2 only scores a BSI of 27, but is able to hold for 6 hours (360 minutes) and scores a total of 9720.
I see this as a way of giving a holder credit not only for the size of their bladder, or only for their endurance, but a combination of the two.
Thoughts?

I thought about this, and I don't see any need to add in time. For a holding contest, I'm assuming that the two are drinking the same amount of water (or drinking water at the same rate), otherwise one could score a very high BSIM by drinking very little. In that case, there's no need to add in time because it's pretty much already in the BSI unit. The volume one can hold (mL) = Flow rate into the bladder (mL/minutes) * Amount of time one can hold (minutes). Since the amount of water entering the bladders is the same, BSI should already represent the endurance of a holder. On the other hand, you could still multiply by time, it would just give time more weight on time over height. Basically, just have the holding contest and compare BSI.

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On 1/21/2014 at 6:16 AM, Racehorse said:

Measured volume isn't a very fair way to compare bladder size or holding ability since larger people will naturally tend to have larger bladders. You need a measure that reflects how big someone is. It seems to me that the Body Mass Index (BMI), used to assess whether someone is overweight, does the equivalent. I've come up with a similar index for bladder size. It uses a similar formula but with maximum volume held instead of body weight. You can find your value from the attached table. Simply find the column for your height, then find the row for the maximum volume that you've ever held, the cell where they meet is your Bladder Size Index.

 

Who's going to be first then?

 

 

post-19587-0-66142500-1390312998_thumb.j

i got 9 points! that doesnt sound horrible right?

Edited by Rileyy (see edit history)
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