"Torso reflex"
https://lifesaving.com/issues-safety-rescue/prevention-and-management-of-torso-reflex/
We still got Idiot fisherman/hunters in bassboats still boating. Water is 37°... No PFD, immersion suit, or even float coats... Just Carhartts with bibs... At least that will help stay warm a little... When those get soaked & heavy and they're at the bottom of the river... /smh
"Torso Reflex, also known as Gasp Reflex , Inhalation Response, or Cold Water Shock, is caused by sudden immersion into water colder than 70 degrees F. Sudden immersion into cold water triggers an involuntary reflexive torso gasp that can cause the person to aspirate water into his/her airway and lungs, which can lead to laryngospasm, disorientation, panic, and the loss of any physical ability to swim or remain afloat."