weather

[MSUSpartan]

Well, as a [former] anatomy & physiology professor, I'm going to disagree with your former professors (or alternatively, your memory of the courses).

While it is true water will not penetrate the skin (for the exact reasons you stated) the outermost layers absolutely do absorb water. This is why your hands get wrinkly after a long bath. Because the absorbed water causes the skin to expand. The rest of your skin is the same way. In fact, water will slowly get absorbed and released with even minor changes in humidity. When it does get absorbed, the lower living layers of your skin become more hydrated (because all of our living cells constantly need water). This in turn required less water from withing the body, and also slows down your body's natural sweating (again the small amount we don't normally notice). Hence you loose less water overall which then kicks in you urine production to keep things balanced.

Again, no. The wrinkling of the skin you speak of only occurs when you are truely soaked, and only for a significant period of time. It is thought (by most), to be a response caused by absorption of water into the keratinocytes (which seems born out histological preparations), but the effect is transient, and there is no evidence that water is resorbed into the blood stream, rather it simply evaporates again. I would also be remiss not to mention that recent research appears to demonstrate that the wrinking response requires live nerve cells, in the dermis, to activate. This suggests it's actually a reflexive response, driven by tiny bundles of smooth muscle embedded in the skin. Those researchers suggested it might actually represent a adaptation to provide more surface area, and therefore grip, when your skin is wet, and therefore slippery.

However this isn't really relevant to the discussion, as the topic was why people experience more urgency, or wetting, when cold and/or clammy or, and not what the effects of long term saturation are.

And the cold cutting off circulation is what happens in moderate to extreme cold and is normally called hypothermia. In low cold situations (like stepping into the ac or grabbing a bag of ice on a hot day) your body absolutely does take advantage of this cooling to keep you core body in temp (no sweating needed). It does this by increasing the blood pressure and by dilating certain blood vessels which lead to the skin. This increased circulation also has the side effect of producing more urine as I mentioned.

You've got this bit precisely backward. In mild to moderate cold, your body does what I previously described. You constrict external blood vessels, conserving warm blood in the core. This drives up blood pressure, causing increased preload in the heart, and triggering baroreceptors in the aortic arch to inhibit sinoatrial stimulation, thereby decreasing heart rate, and normalizing BP.

In moderate to severe cold (hypothermic conditions) the body's ability to thermoregulate begins to break down. The heart begins to race, people begin to sweat, and production of vasopressin (anti diuretic hormone) ceases. Though, again, hypothermia isn't pertinent, as people complaining of a cold/clammy day are typically just uncomfortable, not hypothermic.

[ironhorse]

Wow those are some really detailed explanations! Really smart, educated people here.

[B Brian]

Yeah, thanks for that MSUSpartin. I concede what I learned in college was about 17-18 years ago. You clearly are more current in biology than I am, so I fully accept your explanation. Thanks for being so through.

This does still drive the original question as to why cold/clammy makes us pee more though.

[MSUSpartan]

Frankly I think the cold generally promotes parasympathetic nervous activity, which includes the micturation reflex. I'm not sure if it's intended, or a collateral action.

[Patrick]

When the water hits me in the shower, if there's any liquid in my bladder, it comes out. This may be psychological; however, because of my sphincterotomy, I leak continually anyway. Where the weather really affects my incontinence is when I'm shoveling snow in sub-freezing temperatures. There are few discomforts to equal that of a cold, wet or soiled diaper; this really limits my outdoors activity in the winter.

[B Brian]

That could make sense. It's well known that just the sound of running water alone can make a person pee. Feeling cold or feeling water/humidity isn't that far off.

[Porkchop]

Damn, you guys made me crack out books and stuff...

[justej]

dont worry porkchop. this stuff is waaaaaaaay over my head

[MikePNW]

My urge icon is always a lot worse during cold weather. I have more accidents and go through more diapers each day. My theory is that, because I don't perspire during cold weather, I produce more urine.

[B Brian]

My urge icon is always a lot worse during cold weather. I have more accidents and go through more diapers each day. My theory is that, because I don't perspire during cold weather, I produce more urine.

That's what I said, but apparently MUSpartain says that isn't the case. Meh, just proves I know crap about pee.