Jason Pierce, MSN, MBA, RN for redOrbit.com — Your Universe Online
“Brace yourself; this is going to hurt.” This thought flashes through your mind as your foot slips at the top of the staircase. You tumble downward expecting broken bones and blood. When you finally reach the bottom, you are aching but realize that it could have been much worse. As it turns out, this realization that you could have been injured more severely may not only help to reduce the level of pain that you experience from your tumble — you might actually find it pleasant.
A new study by Norwegian psychologist Siri Leknes, research fellow at the University of Oslo Department of Psychology, suggests that even moderate levels of pain can be a pleasant relief if more severe pain was expected.
“It is not hard to understand that pain can be interpreted as less severe when an individual is aware that it could have been much more painful. Less expected, however, is the discovery that pain may be experienced as pleasant if something worse has been avoided,” Dr Leknes explains.
The study involved 16 healthy participants who agreed to be exposed to varying levels of pain. In one part of the experiment researches applied heat to each subjects´ arm at levels designed to either cause no pain or to cause a moderate amount of pain. In the second part the subjects were repeatedly exposed to heat that caused either moderate or intense pain.
Brain activity was measured using MRI, and the subjects recorded their interpretation of the pain. “As expected, the intense heat triggered negative feelings among all subjects whereas the non-painful heat produced positive reactions,” reported Dr Leknes.
The response to moderate pain, however, was more surprising. In the experiments where moderate pain was the worst alternative, the pain felt was unpleasant. In the instances where it was the best alternative, the subjects experienced the moderate pain as positive.
According to Leknes, “The likely explanation is that the subjects were prepared for the worst and thus felt relieved when they realized the pain was not going to be as bad as they had feared.”
The MRI results also showed that the brain processed the moderate pain differently depending on the context. When experiencing a moderate level of pain in the second part of the experiment there was more brain activity in areas associated with pleasure and pain relief.
The study illustrates that the subjective experience of pain may be determined by the context and expectation of the individual. Dr Leknes points out that this is one possible explanation for why some people enjoy experiences that others find unpleasant or painful.
The findings improve our understanding of how the brain controls the pain response, and may be used to develop new strategies for treating pain.