It turns out that our instinct to say something profane when we experience pain may be good medicine. A small study covered in the journal NeuroReport found that:

Swearing increased pain tolerance, increased heart rate and decreased perceived pain compared with not swearing. However, swearing did not increase pain tolerance in males with a tendency to catastrophise [think that a situation is worse than it really is]. The observed pain-lessening (hypoalgesic) effect may occur because swearing induces a fight-or-flight response and nullifies the link between fear of pain and pain perception.

Researchers got a group of college students to plunge their hands into icy water for as long as possible. One group was told to utter words describing a table. The other was encouraged to cuss, swear, and use words that make sailors blush. Male students using bland language only held out 140 seconds, while those using more colorful language managed 190 seconds. The difference was even greater in women — the working theory is that since a lady curses less, it has more power when she does let loose.

Since pain is often a sign of danger, it is thought that salty language invokes the fight-or-flight response that we might experience in a true emergency situation.  As one psychiatrist put it, “If you’re screaming obscenities, you’re not thinking about your pain. The distraction compartmentalizes the other experience.” The distraction allows us to focus on the tiger, fire, or other danger we may imminently face.

His Take: This is something that I have observed in real, everyday medical practice. Whenever I have to do something to a patient that is painful such as injecting lidocaine before suturing a wound, I encourage patients to curse, scream or whatever they need to let it out.  Most patients seem to find some comfort in a little salty language. Clinical anecdotes that bear out in research are always nice to see.