Monday, June 14, 2004

Men Really are Insensitive Brutes

Women have always maintained as much, of course, but now it seems there's hard evidence in support of the notion.

It will come as no surprise to some... men are less sensitive than women, at least to pain. Researchers have found that the male hormone testosterone masks feelings of discomfort. They believe that such tolerance effects may help men to maintain their stamina in fights, when testosterone levels are high.

"If men are less sensitive to pain, there is more willingness to fight and participate in further fights," says Michaela Hau, an animal physiology and behaviour scientist at Princeton University, New Jersey, and lead author of the study.

The research team gave testosterone implants to male sparrows and measured their reaction times to pain. Testosterone allowed the birds to tolerate discomfort for longer periods, suggesting that the hormone somehow disguises pain.

They determined the normal pain threshold of male sparrows by dangling one of their legs in a beaker of hot water and varying the temperature. "We measured how long it took for the bird to retract its leg," says Hau. The quicker the birds removed their legs, the more pain they were presumably feeling.


The researchers think testosterone triggers a chain of events that leads to an increase in levels of natural painkillers, called enkephalins.

This may occur in humans too. "I don't doubt that there might be some effect of testosterone on pain sensitivity in humans," comments Roger Fillingim, who works on human pain at the University of Florida in Gainsville.

Fillingim thinks there could be a case for administering replacement testosterone to men with chronic pain. These men often take drugs that lower normal testosterone levels, interfering with the natural alleviation of their suffering.
All joking aside, while the research done so far may eventually turn out to apply to humans as well, we aren't birds, and it's far from obvious to me at least that the human nervous system is wired so similiarly to the avian variety to expect such a straightforward generalization. In fact, one could make the argument that men are more sensitive to pain, at least on some occasions - the ordeal of childbirth is something no man ever has to go through, and yet vast numbers of women not only routinely put up with it, but even look forward to repeating the whole process in the future.