[DrK (OP)]

Eleonora asks:

"Why does my dad shiver when he pees?"

Any ideas? Can you explain her dad's toilet quirks?

[Jolly2]

Eleonora asks,

"Why does my dad shiver when he pee's"

can you help help with the uncertainty about these urination antics?

I think you need to give more information, like how old is your father? Does he suffer any underlying condition? Does he stand or sit when he goes to the toilet? Does he shiver at other times or only when  he goes to the toilet? Does he need assistance to go to the toilet?

I think there isn't enough information to answer.

So assuming everything is fine, that he is completely healthy doesn't need assistance to go to the toilet, why would he shiver only when going to the toilet?

It's called post-micturition convulsion syndrome. There are a few ideas, as to why post-micturition convulsion syndrome occurs change in temperature could cause the body to shiver when exposed to a cold bathroom there is the other suggestion

:- According to Caleb Backe, a health and wellness expert for Maple Holistics, your autonomic nervous system plays a vital role in the process of urination.

The ANS is divided into two parts. The sympathetic system is the emergency system that regulates your fight-of-flight reflex. The parasympathetic system relaxes the body and returns it to a resting state.

“When your bladder gets full, it activates nerves in the spinal cord known as the sacral nerves. This brings the parasympathetic nervous system into action, causing your bladder wall to prepare to push urine out of the body,” says Backe. “When urine leaves the body, blood pressure drops, prompting a [reactive response] from the sympathetic nervous system. ”The sympathetic nervous system then floods the body with neurotransmitters called catecholamines in an effort to restore blood pressure.

This creates a mixed signal between the two nervous system components, which may in turn trigger an involuntary pee shiver

"The process of urination is overseen by the ANS, the control center that orchestrates many automatic bodily functions, such as temperature and the beating of a heart, Fulford said. Obviously, urination isn't entirely automatic because we do have voluntary control over when we pee. But before that crucial decision point, urination is largely governed by two parts of the ANS, called the parasympathetic nervous system (PNS), and the sympathetic nervous system (SNS).

When the bladder reaches fullness, tiny stretch receptors in its muscular wall detect the motion of the bladder stretching and activate a set of nerves in the spinal cord called the sacral nerves. In turn, these spring the PNS into action, which causes the muscular bladder wall to contract, preparing it to push urine out of the body. This autonomic process works like an on-off switch, suppressing the instructive nerve reflexes while the bladder is still filling up, but "stimulating those reflexes to act when the bladder is full," Fulford told Live Science.

An odd quirk of this arrangement is that when urine leaves the body, blood pressure drops. "There does seem to be good evidence that blood pressure rises slightly with a full bladder, and that this drops on voiding, or soon after," dr Simon Fulford

"men seem to experience this phenomenon more than women do, which might be explained by the fact that men usually stand when they urinate — possibly intensifying the dip in blood pressure that's thought to precede the shudder.

Whatever the cause, this bodily oddity shouldn't be a cause for concern. "There's not been any substantial research on this subject, but it's a normal bodily function and nothing to worry about," Dr. Grant Stewart, an academic urological surgeon at Cambridge University in England

[Hayseed]

Was it a shiver or a shake?  Some men can experience great pain when urinating with certain infections. 

[evan_au]

Was it a shiver or a shake?

Sometimes a shake gets out the last few drips...

[syhprum]

There is a simple expanation in my case, in the mornihgs I wear  warm track bottoms with no ffies to pee I must remove these almost completely exposing my buttock to the chill air.

[charles1948]

There is a simple expanation in my case, in the mornihgs I wear  warm track bottoms with no ffies to pee I must remove these almost completely exposing my buttock to the chill air.

Have you got any photos of it, I'd be interested to see it for scientific research purposes, not for any other reason

[nudephil]

Cheers everyone.

Answered on the Question of the Week podcast, by both a neurologist and a neuro-urologist: https://www.thenakedscientists.com/podcasts/question-week/why-do-some-people-shiver-when-they-pee