The Gender Pain Gap: the pain perception of men and women

The Gender Pain Gap: the pain perception of men and women

We all know about pain. Pain is an important mode of communication between us and our organism. Contrary to what has long been assumed, it seems that there are differences between men and women when it comes to pain perception. What do we know about this and what are the possible reasons?

What exactly is pain? A definition

John Bonica, an American anaesthetist who is considered the founder of modern pain medicine, defines pain as follows:

“An uncomfortable sensory and emotional experience, which is accompanied by actual or potential tissue damage or is described in terms of this kind of damage.”

Useful pain in the course of our evolution

If we go back quite a bit in natural history, we can see that pain is a very old phenomenon: pain has existed as long as there have been complex nervous systems. And pain never appears by itself. It is always linked with an additional signal which is meant to give more information about its origin – for example, it might occur together with a feeling of pressure, a hot or cold sensation, or stinging, as well as always being paired with information on exactly where the pain arose. Pain serves as a kind of ‘early warning system’. It is meant to urge us to avoid, limit, or end a situation which is either acutely harming us or which would harm us if it continued long-term. Pain has always been useful for our survival.

Because of pain, we pull our hand away from fire, jump back from thorny hedges, and do not walk over sharp stones with bare feet – lots of types of behaviour that prevent potential damage to our body. Pain also helps us, for example, not to overstrain and damage our muscles and joints, or encourages us to protect and treat damaged areas on our skin. Pain is a critical tool in our constant process of learning to find our way in the world: through experiences of pain, we learn to look out for similar sources of danger in future and can even pass on this knowledge to our descendants – a fact which gives humans an evolutionary advantage. Therefore, not only does pain help each person to learn more and more about how they can best protect life and limb over the course of their individual life, but the development of all of humanity benefits from experiences of pain.

The Gender Pain Gap: not all pain is the same

For a long time, it was thought that the perception as well as the effect of pain was the same for men and women. However, there is increasingly growing evidence that this is broadly a false assessment. Fundamentally, there appear to be significant differences between the sexes concerning the so-called “nociceptors”, i.e. pain perception, and this appears to be based on genetic, neuronal, and hormonal factors.

In 2006, a review paper already showed that differences between men and women in the perception of thermal, electrical, chemical, and pressure stimuli could be observed in several experiments. In the experiments, two different thresholds were identified: first, the point at which a stimulus is decidedly perceived as pain for the first time and second, the point at which the stimulus is no longer tolerated by the test subjects (the so-called withdrawal point, e.g., the point at which the hand is pulled back from the stove top). All the studies consistently showed that the thresholds were lower for female test subjects. This means that, for women, the sensitivity to pain was higher and the pain tolerance was lower.

But what is the reason for this difference? In a review article from 2021, a neuroscientist from the University of Oxford comes to the conclusion that women generally have a significantly higher risk of developing chronic pain than men. He states that this can be observed with head and back pain in particular. The author gives multifactorial reasons for this, but the influence of hormones on the occurrence of pain seems particularly important. According to this, sex hormones affect the body’s neuronal processes, which in turn affect the processing of pain signals, among other things. Additionally, sex hormones influence immuno-dependent processes which also affect the processing of pain, often by means of messenger substances.

How men and women draw different conclusions from pain

However, differences between men and women can be observed not just in the development of pain, but also in the individual approaches to it. In 2019, a study was able to show that, for men, the issue of ‘injury’ is paramount when they experience pain; the feeling of being robbed of their invulnerability through the experience of pain was described much more powerfully by the male test subjects than by the female test subjects. According to the study, a typical male strategy for handling the feeling of pain and vulnerability that we might call “activity pacing” can be observed, namely a noticeable reduction in activities or plans, as well as taking more breaks, corresponding to the particular pain situation. It is especially noteworthy that women tend to do the exact opposite when they feel pain, namely overdo it, i.e., overexert themselves, carry out their plans as intended despite the pain. There is an increase in activity for women and a decrease in activity for men.

The purpose of archaic pain strategies

If we take look at the beginnings of the human species, we find an indication as to how evolution might have contributed to these different handling strategies. According to our understanding today, the archaic distribution of roles looked something like this: in hunter-gatherer times, the man would provide food for his family by hunting, while the woman was entrusted with caring for the offspring. If we now imagine that the hunter is injured or sick, it is important to ensure that their strength is recovered as quickly as possible. If the hunter is inactive for too long, the whole family will starve. The harshness of the wilderness in hunter-gatherer times meant that only a hunter who was at full strength could hunt successfully. The quickest possible, sustainable recovery of the hunter was therefore the top priority and all activities that used up bodily resources which were required for recovery needed to be suspended. However, things are completely different for the person who is responsible for taking care of the children: the offspring need to be looked after constantly in order for them to survive and caring for the children, if it is to be successful, must be prioritised over the sustainable recovery of the person responsible for them at all times.

Self-exploitation as an evolutionary dead end?

It could be argued that, ultimately, the family will not benefit from the children’s caregiver burning the candle at both ends and therefore, while fulfilling their role in the short-term, not being able to survive healthily in the long run. What does it achieve if this person in fact ends up endangering the family’s continued existence through prolonged self-exploitation? The answer is that, from an evolutionary perspective, it is simply not important for particular individuals within a species to lead a long, healthy life. The only thing that counts is the continuation of the species, and this is guaranteed by producing enough offspring which are successful in an evolutionary sense. Put very simply: when as many healthy offspring as possible have been brought into the world and have been brought up so successfully that they can ensure the continued existence of the species in the form of their own family, the previous generation has served its purpose. As harsh as this may sound to our ears today: the continuation of the species is better served when each generation optimally uses its resources in order to produce the maximum number of successful offspring – and less well served when all individuals rest at the ‘wrong’ time, i.e., during the most productive time in terms of offspring, in order to ultimately live a longer life at the expense of the number of successful offspring.

New strategies for everyone

Today, we are no longer living in the Stone Age and the fact that we can consciously decide to not merely devote the individual to the continuation of the species can be described as one of the biggest achievements in human development. It is a rule of our – in today’s sense of the word – humane treatment of each other that each person should be able to have a life which is as free of suffering as possible. For the way we treat pain, this means: wherever possible, the pain should be alleviated rather than endured. Particularly for women, whose pain perception is more sensitive, who are more at risk with regard to the chronification of pain, and who are more susceptible to handling their own pain in an unhealthy way, the motto must be: stop the pain in time. For headaches, which impact female patients significantly more than male patients worldwide, it is therefore even more important to encourage a careful approach.