Do Men and Women Perceive Pain Differently?

We all experience pain, but apparently not in the same way. One factor influencing pain perception is biological sex: some chronic pains are more common in women, such as migraines, while others are more prevalent in men, such as gout, a type of arthritis.  The reason for this difference is not entirely understood, but it may partially stem from variations in brain activity between men and women and their respective sex hormones. However, these differences may originate even before the brain processes the pain, at the point where the body first encounters the pain-inducing stimulus.

Sometimes we accidentally touch a hot object, like a pot or a tray fresh out of the oven. Immediately after our hand comes into contact with the heat source, information about its high temperature travels from the hand to the brain, where it is interpreted as a sensation of pain. This unpleasant sensation prompts us to pull our hand away, preventing prolonged contact with the dangerous object that could harm or damage our body.

We sense pain through alarm receptors, or nociceptors, which are nerve cells found in the skin, muscles, joints, and many internal organs. These receptors respond to external stimuli, such as extreme temperature or strong pressure, and signal the brain about potential harm. A recent study found differences in the functioning of nociceptors in males and females. These differences may potentially explain some of the disparities in pain perception between the sexes.

Migraines are one example of chronic pain more commonly experienced by women. Woman experiencing a headache | fizkes, Shutterstock

Painful, but Different

The study focused on activation thresholds, a key aspect of how alarm receptors function. These receptors are constantly exposed to a range of stimuli of varying intensities, and it is therefore preferable that they do not respond strongly to harmless inputs. For example, we don’t experience the touch of a shirt on our skin as painful, unlike the sharp ache from hitting a table leg. The receptor’s activation threshold is the level at which a stimulus is recognized by the brain as painful and potentially dangerous. A lower threshold means pain is felt in response to weaker stimuli. Previous studies have found that women generally have lower activation thresholds than men, which might explain why certain stimuli feel more painful to women.

The activation thresholds of receptors are not fixed. Inflammation or tissue damage can alter the threshold, as can substances secreted by the body. For instance, studies in female rodents show that exposure to prolactin —a hormone produced by the pituitary gland that promotes milk production—lowers the activation threshold of pain receptors.In males, prolactin plays roles in regulating testosterone levels and sperm production and plays an essential role in the immune response in both sexes. Another substance, orexin B, is secreted in the brain and influences the activation threshold of alarm receptors.

Given these findings, the researchers sought to test whether these substances affect alarm receptor activation differently in each sex. They took tissues from mice, monkeys, and humans of both sexes, exposed them to prolactin, and used electrodes to measure the activation of alarm receptors signaling spinal cord damage. They repeated the process with orexin B. The experiment revealed an intriguing phenomenon: in all the animals tested, prolactin influenced the activation of pain receptors in females but not in males, while orexin B affected alarm receptor activation in males but not in females. This suggests a fundamental difference between the sexes in how alarm receptors function.

There appears to be a fundamental difference between males and females in the functioning of alarm receptors. Flashing red emergency light | Lemonsoup14, Shutterstock

Towards Personalized Pain Medicine

Although this study is basic, its findings hold significant importance. If alarm receptors function differently in males and females, a patient’s sex may need to be considered when prescribing painkillers and determining their purpose. The difference in how substances secreted by the body affect alarm receptors could also be significant for long-term treatments of chronic pain conditions. Further research in this area could  deepen our understanding of how pain is generated in the body and how it can be effectively controlled. This knowledge has the potential to revolutionize pain management by enabling the development of treatments tailored to the patient’s sex. Such personalized approaches would ensure that every individual—male or female—receives care optimized for their physiological needs.