While it may seem obvious to some that pain is perceived differently between males and females, the research previously conducted about pain didn’t necessarily suggest that to be the case. That’s because pain research has conventionally used male study subjects. However, recent studies have demonstrated that there are indeed real differences in how the sexes experience pain, and this has opened the eyes of pain researchers – and biomedical researchers as a whole — to the spectrum of biological responses across sexes.
How is pain perceived?
At its core, a painful sensation is meant to be a signal to your body that something is — or may be — wrong. It warns your brain that your body is being exposed to something potentially harmful such as excessive heat, toxic chemicals, or tissue damage.
Pain receptors send this information to your spinal cord, eventually activating other nerves that relay this information to your brain. Your brain then recognizes and perceives the painful stimuli and coordinates the appropriate responses so that your body deals with the pain appropriately.
There are, however, different types of pain. There’s the fast kind of pain, such as the pain from accidentally touching a hot stovetop that immediately results in you yanking hand off the hot surface. There’s also the slow kind of pain, such as the throbbing pain that ensues after the injury has physically healed. The latter type of pain occurs because the pain receptors have become hypersensitive so that stimuli that previously drew no pain response now feels painful. This type of pain is also known as chronic pain.
What are the differences in pain perception between the sexes?
Researchers have found that male and female mice use different immune cells to transmit the sensation of chronic pain, effectively leading to two separate pathways for controlling pain. Furthermore, they discovered that testosterone was the main hormone responsible for the switch between these two pathways. Castrated male mice, which have low levels of testosterone, were found to use the same immune cell mediator as female mice, and administration of testosterone to these castrated mice caused the pain pathway to switch back to the other pain pathway. There is also evidence supporting the idea that there are different cells between the sexes which mediate the sensation of chronic pain in humans as well.
Memory also plays an important role in the perception of pain. A research team found that males remember pain more clearly, which causes them to anticipate and become stressed about later pain. This causes them to become more sensitive to later pain. The experiment has been conducted on both mice and humans with similar outcomes.
Although it might be tempting to use these new research findings to develop pain drugs targeted to a specific sex, this might not be enough. There are many other contributing factors beyond the sex of a person that affect the perception of pain, including a person’s age, hormone levels, genetics, and anatomical development. And what about transgender folks or folks who don’t fit into a binary definition of sex and gender? Little research has been done on pain perception among these groups of people.
However, it is true that sex differences do cause people to respond to drug treatments differently, and drug trials should check whether a certain drug is more effective in men or women. In addition, sex differences should be considered in biomedical research, because it does contribute to the development of personalized treatment plans. Finally, more research needs to be done for those who don’t fit into the binary model of gender and sex. It’s hard for science to come up with adequate solutions for everyone if a good chunk of the population isn’t represented in the experimental group.
Information sources:
https://www.mcgill.ca/newsroom/channels/news/men-and-women-remember-pain-differently-293050
Image sources:
https://pixabay.com/photos/figure-man-stand-back-pain-1707104/
https://pixabay.com/illustrations/doctor-research-chemical-observes-3822863/