The other night, I noticed something weird. I was lying in bed, wearing my usual pajamas, and yet I was feeling colder than usual. Same blankets, same clothes, but as the minutes passed, I kept getting chillier. This happens some nights but not all nights even though I keep the house at the same temperature.

At first, I chalked it up to not moving around much. But then I realized something else: I really had to pee. That’s when a thought hit me, Could having a full bladder make you feel cold?

Turns out, yes. Here’s why:

The Bladder–Body Temperature Connection

When your bladder fills, it stretches and activates nearby nerves connected to your autonomic nervous system (the part of your body that handles things like heart rate, digestion, and temperature control without you thinking about it).

Blood flow shift – Your body may subtly redirect blood flow toward your core while you’re “holding it,” pulling warm blood away from your skin. Less warm blood at the surface = feeling colder.

Cold diuresis effect – There’s also an evolutionary link here. In colder conditions, your body shunts blood away from the skin to conserve heat, which increases blood pressure. The kidneys respond by producing more urine. So the “full bladder + feeling cold” combo isn’t just coincidence.

Why Peeing Can Make You Even Colder

If you’ve ever gotten the pee shivers, here’s what’s going on:

Parasympathetic surge – Letting go triggers your “rest-and-digest” system. Blood vessels dilate, warm blood flows back toward your skin, and the sudden shift can make heat escape from your core, leaving you chilled.

Shiver reflex – The bladder’s nerves also connect to reflexes in your spine that can trigger a brief shiver, like your body is “resetting” after the tension of holding it in.

Bottom Line

That bedtime chill might not just be your room temperature, it could be your bladder playing thermostat. If you notice you’re feeling colder and also really need to go, it’s worth making that quick bathroom trip. You might be surprised at how much warmer you feel afterward (and how much better you sleep).