&%!!# helps when you're hurting
In 2009, British psychology researchers reported the results of a study that showed swearing altered pain perception. The study volunteers could hold a hand in ice-cold (41 degrees F) water about 40 seconds longer if they repeated a swear word of their choosing instead of a control word (one of five words they had picked for describing a table).
Swearing was also associated with an increase in heart rate, so the psychologists theorized that the body's fight-or-flight response is activated by the emotions that swearing produces. Pain perception takes a backseat once the body is in fight-or-flight mode.