In the study, researchers from the UK's Keele University asked participants for five words they'd likely use after hitting their thumb with a hammer; the first word listed would be their go-to profanity during the experiment. (They were also asked to list five boring words -- ones they'd use to describe a table.)
Participants were then instructed to submerge their unclenched hand in a container of 41-degree water, and keep it there -- while repeatedly cursing -- for as long as they could. Before and after plunging their hands into the chilly water, their heart rate was recorded. And after they could no longer stand the cold temperature, they were asked to rate the amount of pain they were in, too.
What's surprising is that the researchers had thought that swearing would make the cold water feel much colder, lowering the participants' tolerance for pain and heightening their perception of it. "In fact, the opposite occurred -- people withstood a moderately to strongly painful stimulus for significantly longer if they repeated a swear word rather than a nonswear word," write the team, led by Keele University psychologist Richard Stephens, in the journal Neuroreport.
From the way participants' heart rates accelerated post-swearing, the psychologists believed their fight-or-flight response had been activated -- that may be because cursing can amp up feelings of aggression. (Think of a bunch of rowdy NFL players psyching each other up before a big game.)
Interestingly, women reported feeling less pain after swearing a blue streak. (Hilariously, the researchers report that cussing "did not increase pain tolerance in males with a tendency to catastrophise." That's the polite British way of saying some of the boys were total drama queens.)