By Keith Mulvihill

NEW YORK, Mar 02 (Reuters Health) - Men and women appear to react differently to a loud startling noise, new research suggests. Women, it seems, can be frightened by a sound more easily than men, and in response, show an increased tolerance to pain.

Men, on the other hand, find a loud noise more startling than fearful and actually become more--not less--sensitive to pain, according to Dr. Mary W. Meagher, a psychologist at Texas A&M University in College Station, Texas. Meagher and colleague Dr. Jamie Rhudy report their findings in the February issue of The Journal of Pain.

"We can't say, on the basis of this study, that men and women have different reactions to noise as a stressor, but it suggests that women have a lower threshold to experience noise as stressful," Meagher explained in an interview with Reuters Health.

In the study, 20 men and 20 women were exposed to a loud sound similar to a fire alarm in an office building. For some of the participants, the sound came without warning while others were told a sound was coming but it never did. All of the study participants answered questions after the experience and described their emotional state.

The women were more likely to say that the noise made them afraid. Afterward, the women also showed an increase in their ability to withstand a painful stimulus, an effect that lasted up to 8 minutes after the sound, according to the report.

The men were not as reactive to the noise and reported that they were not afraid. The men were more likely to say that they felt surprised by the noise, but when exposed to a pain stimulus, the men were less able to withstand the pain, Meagher noted.

"The gender difference might disappear if we increased the intensity of the noise bursts for men. With more intense noise they will probably show the same effect observed in the women. However, our data suggest that women may be more sensitive to noise stress than men," Meagher told Reuters Health.

From an evolutionary point of view it makes sense that fear would decrease a person's sensitivity to pain, the report indicates.

"During a life-threatening situation, feeling pain would get in the way of survival, so the body reacts by shutting off the pain response," Meagher said. "Anecdotally, this has been reported by men in combat who did not realize that they had been shot until after they made their way back to safety."