Anyone who has taken the time to make it through my entire post on performance under pressure knows that I have spent a lot of time reading and thinking about stress and the ways it affects us in emergency medicine. I read hundreds of articles and books when preparing my lecture and post on the topic, which is why I was particularly surprised when I was asked to comment on the literature discussing gender differences in the stress response. Despite all my reading, I hadn’t come across a single paper on the topic.
We have all heard about the “fight or flight” response. It is supposed to be the natural human response to stress – a description of the end effects of a surge in our sympathetic nervous systems. In my original post, I take “fight or flight” as a given (although I have always argued that it is overly simplistic and leaves out one of the most common responses to stress: freezing). However, it turns out that essentially all the research that supports the classic description of “fight or flight” was done in males (and primarily in male rats), a shortcoming that was recognized almost two decades ago. (Taylor 2000) (I will leave for another time the bigger issue of how easy it is to overlook research focusing on gender issues or females specifically.)
It turns out, if you actually include females in studies of stress, you see different patterns of behaviour (keeping in mind the massive caveat that most stress studies are still using relatively simplistic models in place of more complex, real-world human behaviour). Instead of running or fighting, females are more likely to employ strategies that including hiding, caring for others, and forming social groups for support. In contrast to “fight or flight”, the female response to stress has been described as “tend and befriend”. (Taylor 2000)
The core neuroendocrine responses to stress seem to be similar regardless of sex: the hypothalamic pituitary adrenal (HPA) axis is activated, resulting in the release of catecholamines, cortisol, vasopressin, and oxytocin. However, traditional descriptions of the HPA axis have underestimated the importance of oxytocin, as well as the modulating effects of estrogen and testosterone. In experimental settings, injecting stressed animals with oxytocin results in relaxation, reduced sympathetic activity, and reduced fearfulness. (Uvnäs-Moberg 1997) In other words, oxytocin seems to produce the opposite of a “fight or flight” response. Females release more oxytocin than males when stressed, and estrogen upregulates the activity of oxytocin, whereas testosterone inhibits its effects. (Taylor 2000; Jezová 1996)
A number of evolutionary explanations have been suggested for the differences in sex based stress responses. (I always find these evolutionary arguments fascinating, but I am generally skeptical of their validity.) The idea is that if you have a small child with you, fighting is a poor option because of the risk of losing, and running away is inefficient while carrying offspring. Therefore, the ideal evolutionary response to stress may have been remaining calm, grouping together, and caring for infants, which calms and quiets the infants and increases one’s ability to hide. (Taylor 2000)
The evolutionary biology arguments are interesting, but probably a little superficial. Humans, whether male or female, are not particularly well adapted for either running or fighting when you consider the foes we would have encountered. My (very cursory) understanding is that is was tools, intelligence, and teamwork that gave humans an evolutionary advantage. Humans are not solitary animals. Befriending, in that context, would seem like a universal quality. Fight, flight, tend, and befriend are probably all part of the complex human stress response.
This gets to the very core of any discussion of differences based on sex or gender: it’s complicated. (For a great primer on sex, gender, and their influences on biology and behaviour, see this post on the seX and whY blog by Dr. Jeannette Wolfe.) There is no clear dividing line based on either sex or gender. Behaviors aren’t binary; it’s more complicated than that. Biology forms a foundation for our behavior, and there are clearly sex based biologic differences, but that biology is complex, and not cleanly divided based on chromosomes. That central biologic tendency is then influenced by and interacts with social, cultural, cognitive, and emotional factors than make any discussion of human behaviour overwhelming complex, but also incredibly interesting.
The literature exploring sex based behavioural differences is extensive, and I have only scratched the surface. However, thanks to some excellent suggestions from Dr. Jeannette Wolfe, I have now read a number of fascinating studies illustrating sex based differences in stress responses. There are biochemical differences between males and females, and stress responses can be altered by administering exogenous hormones. (Taylor 2000; Cueva 2015; Uvnäs-Moberg 1997; Jezová 1996) There are fMRI studies that illustrate males and females activate different areas of their brains when exposed to the same stressful stimuli. (Seo 2017; Lighthall 2012) There are behavioural studies that indicate males and females behave differently under stress, using different strategies, with different risk tolerances, and at different speeds. (Lighthall 2012) Males and females may also employ different coping strategies after stressful experiences. (Repetti 1989; Sherman 2016)
Potential differences in sex based stress responses deserve our attention in emergency medicine. I am, however, hesitant to limit the discussion to sex or gender based differences. There are numerous shortcomings in all of the studies here, and the underlying complexity of human behaviour is likely to overwhelm any simple, dichotomous differences that might exist between the sexes. Reading these studies, I recognized my own stress responses in both the descriptions of stereotypical “male” and “female” responses. There are times that stress might trigger a fight or flight type response in me, but there are also times when comradery and “befriending” are my chosen coping mechanism.
My major take away from this literature is the recognition that different people will respond to stress in different ways.
I do think it is important to recognize the variety of possible stress responses when working in emergency medicine. Whenever I have lectured on this topic, different performance tools seem to resonate with different members of the audience. Techniques designed to stop negative self talk may be more applicable to people who tend to ruminate under stress. Breathing techniques might be more important for people with a strong physiologic response to stress. Cognitive stop points may be most important for people who find themselves constantly rushing when stressed.
Although some behaviours, and therefore some performance techniques, might broadly speaking be more applicable to males or females, I think it is most important to recognize your own personal tendencies under stress. I used to think of performance techniques as universal interventions, but after reading this literature I think they can be personalized. Before incorporating new stress management tools into practice, I think it is important that each individual consider his or her own stress responses. Perform a self-diagnosis, or recruit someone to observe you under stress. Then, once you have a sense of your normal reactions to stress, you can choose the techniques that are most likely to help you perform.
It is also essential that we understand the variety of normal stress responses when considering the performance of our colleagues and students. Some people rush to action in the face of stress. Rapid intervention might be laudable, but if alternatives are not considered, it might also lead to more errors. Other people, when faced with a stressful situation, spend more time considering options before committing themselves to a course of action. This might result in increased accuracy, but may be harmful if it results in a prolonged delay. There is not one ideal response.
However, I think we tend to judge each other based on our personal stress responses. When I think a resident is taking too long to act, I might assume he doesn’t know what to do, or that he has frozen in the face of stress, and jump to take control of the situation myself. In reality, I don’t know his thoughts unless I ask, and he may have just been taking a few extra seconds to consider the best course of action. On the other hand, if a colleague jumps to action while I am still considering the details, I might consider him a “cowboy”. Rather than rushing to judgement, it might be helpful to consider individual differences in decision making and stress response.
Likewise, we all cope with stress differently. Some of us need to be left alone in the immediate aftermath of a bad resuscitation. Others cope better in the presence of others, talking and joking. Trying to force a single coping mechanism on everyone is unlikely to be helpful.
Ultimately, the revelation that there are sex based differences in stress responses has left me with more questions than answers. I am extremely thankful to Dr. Jeannette Wolfe for bringing this literature to my attention. If you have not discovered her wonderful new podcast, seX and Why, it is a great resource that explores the impacts of sex and gender on behaviour, biology and medicine. I can’t recommend it enough. We spent many hours discussing stress, performance under pressure, and some of these papers on sex based differences. If you want to hear more on the topic, Jeannette edited that conversation down into an excellent 3 part podcast that can be found here.
Cueva C, Roberts RE, Spencer T. Cortisol and testosterone increase financial risk taking and may destabilize markets. Scientific reports. 2015; 5:11206. PMID: 26135946
Jezová D, Juránková E, Mosnárová A, Kriska M, Skultétyová I. Neuroendocrine response during stress with relation to gender differences. Acta neurobiologiae experimentalis. 1996; 56(3):779-85. PMID: 8917906
Lighthall NR, Sakaki M, Vasunilashorn S. Gender differences in reward-related decision processing under stress. Social cognitive and affective neuroscience. 2012; 7(4):476-84. PMID: 21609968
Repetti RL. Effects of daily workload on subsequent behavior during marital interaction: the roles of social withdrawal and spouse support. Journal of personality and social psychology. 1989; 57(4):651-9. PMID: 2795436
Seo D, Ahluwalia A, Potenza MN, Sinha R. Gender differences in neural correlates of stress-induced anxiety. Journal of neuroscience research. 2017; 95(1-2):115-125. PMID: 27870417
Sherman GD, Rice LK, Jin ES, Jones AC, Josephs RA. Sex differences in cortisol’s regulation of affiliative behavior. Hormones and behavior. 2017; 92:20-28. PMID: 28011060
Taylor SE, Klein LC, Lewis BP, Gruenewald TL, Gurung RA, Updegraff JA. Biobehavioral responses to stress in females: tend-and-befriend, not fight-or-flight. Psychological review. 2000; 107(3):411-29. PMID: 10941275
Uvnäs-Moberg K. Oxytocin linked antistress effects–the relaxation and growth response. Acta physiologica Scandinavica. Supplementum. 1997; 640:38-42. PMID: 9401603