為什麼男人撒尿的時候會震一震呢?

尿震，民間又稱之為尿搖頭；醫學上稱排尿後抽搐症（英語：Post-micturition convulsion syndrome），指小便後身體不由自主地震顫，但這個現象通常不被認為是疾病；打尿震者多為男性。而我所問過嘅女生十之八九唔會打冷震嘅。。。

原因有︰
引發尿震的原因尚不太清楚，但一般的解釋有三個：
1. 排尿令身體突然失去大量熱量引起寒顫、
2. 排尿刺激陰莖末端的神經而引起神經系統的反射、
3. 副交感神經的反射。

因為這是人體自我保護的一種反應

唔知你發唔發覺
尿係暖既呢

因為尿儲係人體的時候會被體溫變暖
當你小便時,因為身體突然快速失溫
腦部收到信息,令肌肉摩擦產生熱力以保暖
這就是俗稱的"打冷震"

這和冬天身體會打冷震一樣
都是令身體保暖

2008-01-26 13:46:18 補充：
小便時打冷震會俗稱"打尿震"

Because that is about your hormones change. Is a science question or something like that. In general, hormones regulate the function of their target cells, i.e., cells that express a receptor for the hormone. The action, or net effect of hormones is determined by a number of factors including its pattern of secretion and the response of the receiving tissue - the signal transduction response.

Endocrine hormone molecules are secreted (released) directly into the bloodstream, while exocrine hormones (or ectohormones) are secreted directly into a duct, and from the duct they either flow into the bloodstream or they flow from cell to cell by diffusion in a process known as paracrine signalling.