Researchers at Keele University in the UK have found that swearing can have a painkilling power, especially for people that don't regularly curse. To test their theory, Dr. Richard Stephens and other scientists conducted an experiment with student volunteers. The students were asked to submerge their arms into a bucket of icy water, while repeatedly uttering a swear word. (It's not clear what the specific swear word was, but we're naturally assuming the worst.) They then repeated the experiment, while repeating a "harmless" word rather than a swear.
The results showed that volunteers were able to keep their arms in the icy water longer when they were swearing than they could when they were uttering the harmless word. According to the scientists, these results demonstrate the link between swearing and an increase in tolerance to pain. It should also be noted that for the volunteers who weren't habitual swearers, swearing was four times more likely to ease the pain caused by the icy water.
Why does this painkilling effect kick in when we swear? One theory the researchers are considering, is that swearing — an act of aggression, especially if it's not a part of your daily vernacular — triggers your fight-or-flight instincts, which can ramp up your tolerance to pain.
Of course, if your everyday conversation rivals Christian Bale's, not only are you ill mannered, but you're also less likely to experience the soothing effects that a well-timed, but not oft-used, F word can offer.