Shouting 'ow' or 'ouch' helps alleviate pain, study finds. AFP

Saying "ow" helps people to tolerate pain by disrupting messages being sent to the brain about the discomfort, scientists have discovered.

Published in the Journal of Pain, scientists from the National University of Singapore were looking to find out why we cry out when in pain – a seemingly instinctive response that starts from birth.

Previous research has suggested saying ow or ouch serves a communication purpose – to let others know you have been hurt, to prompt caring behaviour, as well as to indicate a potential danger.

However, scientists have now found it also helps to alleviate pain. They tested the purpose of vocalising pain by asking people to plunge their hands into extremely cold water.

Of the 56 participants, those who said ow could hold their hand in the ice water for up to three-and-a-half minutes longer.

"On separate trials, they said 'ow', heard a recording of them saying ow, heard a recording of another person saying ow, pressed a button, or sat passively," the authors wrote. "Compared to sitting passively, saying ow increased the duration of hand immersion."

Findings also showed that hearing a recording of your own "ow" or another's did not increase pain tolerance, suggesting vocalisation does not only serve a communicative purpose.

"These results provide first evidence that vocalising helps individuals cope with pain. Moreover, they suggest that motor more than other processes contribute to this effect."

Researchers believe that the muscle movements involved in making the "ow" sound (it is similar in a number of other languages) may be involved in helping reduce pain: "Shared among these is a sound during which the mouth simply opens, the tongue lies flat and the lips remain unrounded.

"It is a simple sound that requires little articulatory control, while maximising volume output. As such it may be used quite easily and effectively when in pain."