"Caught cold": Why do boxing fans say this?

[DiegoFuego]

I'm aware, I was merely explaining what coufsax meant...

we know what he meant. we're pointing out how it's irrelevant. if you hit me today, I'm not going to still be feeling it in September

[etlux]

not sure which type of 'caught cold' you guys are referring to, some sort of generic colloquialism that just means a person was KTFO fast or the real version which is scientifically based.
But in real terms caught cold means that the other fighter didn't warm up properly in the dressing room (thus their body still "cold") and what this means is that their muscles aren't as loose, they are still tense and rigid and not able to dodge things and mov fluidly.
The most blatant example of this was the Golota vs. Lamon Brewster fight. Golota came out visibly "cold" i.e. no sweat on him at all, like he didn't warm up whatsoever in the dressing room. After the fight Brewster's team from waht I can remember said explicitly that they saw that Golota was not warmed up properly and Brewster who came out in a sweat WAS, so that is why Brewster immediately went after Golota for the knock out, because he knew that someone as stiff as Golota who was caught cold as well, will be extra stiff and extra susceptible to the knockout. So that's the perfect example of someone who was 'caught cold' and knocked the hell out for not warming up properly in the dressing rooms.
Now you know why fighters warm up and practice in the dressing rooms, it's to warm up their body and their muscles, loosen them up so that they're not 'caught cold' in the first few rounds and knocked out.