Simple biology question

[DownUnderRoo]

This should be simple, but since I've never measured it...

If I drink 2 litres in the morning, will 2 litres come back out as urine later or more like 1.5l or even less (rest absorbed, transpired, etc).

Basic question: Amount of fluid I drink at work equals diaper capacity minimum for work?

 

[CPDude]

I could not measure that without a condom catheter and a tube and a measuring bottle. and they are uncomfortable. No thank you. The nurses did that to me once in the hospital to get a urine sample.

 

[Tenawearer]

Half of what you drink takes about a week to pee out. You urinate less than than you drink because of sweating and you also breath moisture out. Not helpful for the capacity question though...

 

[Anemone]

It's also worth noting that the capacity of a nappy is entirely notional - you will not get peak performance if you do things like move; sit; or urinate into the same area.

A bladder should have a capacity of around 700ml, which should give some indication as to what a wetting represents.

As noted above the body uses much of the water to consumes. Water leaves the body through sweat, breath and also the bowels as well as in the form of urine. Food also contains a quantity of moisture, which would need to be factored into expected throughput.

 

[AnonJohn]

You can measure it readily enough if you weigh your diapers before and after and subtract. And measure liquid intake. That's how it's done for babies! ☺

It will, on average, be a bit less than you drink, for the reasons Anemone noted (sweat, breath, bowels, food). It will also vary about that average for many reasons (e.g. exercise levels, salt intake)

In general a health adult produces 0.5-1.5 mL/kg/hour.

I think that if I am inactive and hydrating a lot that out is almost equal to in.

 

[wiliawi]

If you really wanted to measure while still wearing your diaper, you could weigh you wet diaper and compare it to their dry weight. I water is 8.3 lbs per gallon. So if a diaper was 4.5 lbs wet and .25 pounds dry, then it would be holding 4.5-.25=4.25 lbs of water/pee or about .51 gallons which would be about 33oz

 

[wiliawi]

You can measure it readily enough if you weigh your diapers before and after and subtract. And measure liquid intake. That's how it's done for babies! ☺

It will, on average, be a bit less than you drink, for the reasons Anemone noted (sweat, breath, bowels, food). It will also vary about that average for many reasons (e.g. exercise levels, salt intake)

In general a health adult produces 0.5-1.5 mL/kg/hour.

I think that if I am inactive and hydrating a lot that out is almost equal to in.

You beart me to it... lol

 

[TigerDL]

You can measure it readily enough if you weigh your diapers before and after and subtract.

If you really wanted to measure while still wearing your diaper, you could weigh you wet diaper and compare it to their dry weight. I water is 8.3 lbs per gallon. So if a diaper was 4.5 lbs wet and .25 pounds dry, then it would be holding 4.5-.25=4.25 lbs of water/pee or about .51 gallons which would be about 33oz

Does this account for urine being not pure water? Wouldn't the density of pee differ from the density of water, even at least a little bit? and that density would also change based on your hydration levels and stuff (like how your pee comes out more yellow or clear).

 

[Tenawearer]

Darker the colour the more impurities in your urine. The clearer the better. Drinking more water helps to flush out your system. Water not cola, orange juice ,fizzy crap.

 

[wiliawi]

I doubt it would differ much. Maybe a little, but I think it would be within an ounce or two.

 

[AnonJohn]

Does this account for urine being not pure water? Wouldn't the density of pee differ from the density of water, even at least a little bit? and that density would also change based on your hydration levels and stuff (like how your pee comes out more yellow or clear).

Quite right. But I don't think it makes too much of a difference. If we use seawater as a proxy for saline, mineral rich water, it is 2-3% denser than plain water.

 

[Edgewater]

And our Math and Science Teachers would be proud, if not a bit surprised regarding the reason.

And as so well stated by Anemone one needs to consider the ability of the diaper to accept and move urine within the diaper.

 

[OnePiece]

Does this account for urine being not pure water? Wouldn't the density of pee differ from the density of water, even at least a little bit? and that density would also change based on your hydration levels and stuff (like how your pee comes out more yellow or clear).

The difference in density in water and urine is negligible in this context.

 

[OnePiece]

This should be simple, but since I've never measured it...

If I drink 2 litres in the morning, will 2 litres come back out as urine later or more like 1.5l or even less (rest absorbed, transpired, etc).

Basic question: Amount of fluid I drink at work equals diaper capacity minimum for work?

It's not so simple after all
First; You should not drink 2 liters in a short period of time. 2 liters can be enough for the whole day,
but that depends on a lot of factors. I'm closer to 3 liters.

There is a big time lag from drinking to urination. There are factors like sweating, food type, type of drink (coffee),
physical intensity, psychological stuff (like sound of running water), diseases etc.

The short answer is you can never know for sure how much diaper capacity you will need.
Only experience will give you an answer, and there will still be days when you get it wrong.
My advise is to wear a diaper with good capacity and bring extra changes for security.
It's better to bring back home a dry diaper than a pair of wet pants.

 

[star]

You can measure it readily enough if you weigh your diapers before and after and subtract. And measure liquid intake. That's how it's done for babies! ☺

It will, on average, be a bit less than you drink, for the reasons Anemone noted (sweat, breath, bowels, food). It will also vary about that average for many reasons (e.g. exercise levels, salt intake)

In general a health adult produces 0.5-1.5 mL/kg/hour.

I think that if I am inactive and hydrating a lot that out is almost equal to in.

There is a hysteresis effect. At low levels of intake output is significantly less than intake. As we reach optimum hydration, output and input volumes begin to converge. If we become over-hydrated, excretion will meet or even exceed intake

As a side note, if hydrating to that level, please ensure you get electrolytes, specifically sodium. A pinch of salt in a bottle of water is fine.

 

[grst]

In my personal experience it seems to depend on how well hydrated I am to begin with. If my urine is already mostly clear and I chug a whole 500 ml bottle of water, pretty much all of it is going to come out in the next 30-45 minutes. However, when I wake up my urine is usually pale yellow. The first two hours I’m awake I usually drink two bottles of water. Out of that 1000 ml of water I would say that I probably only end up peeing out about 300-400 ml of it. Obviously throwing physical activity in the mix makes a difference too. I started hiking just a few months ago to try and get myself more physically active. I have a 3L water bladder that I drink from when I hike. I will typically go through that entire 3L. However, since my body is using it, I have yet to go on a hike where an XL Goodnite can’t handle the urine output. I usually hike between 8-10 miles over 4-5 hours.