Resilience means to most people achieving a positive outcome in the face of adversity.
(McEwen, 2015)
Let’s take a moment and appreciate our ability to cope with stress in our life. Although we might still think of stress as terrible and feel stressed-out sometimes, we have actually successfully handled tens of thousands of stressful moments by now in our life.
How does our brain and body accomplish this amazing work?
For a healthy body, the internal, physical, and chemical conditions generally remain steady. In other words, for example, our temperature, pH concentration of sweat, and chemical concentration are generally kept in a certain range. In this way, our bodies are in balance.
When facing stressful events, the body responds by releasing chemical mediators which are in control of our physiologic reactions (e.g., increased heart rate and blood pressure) and help our brain adapt to the stress in the short run, which will cause a temporary unbalanced condition. In a healthy brain, these mediators are turned on when needed and turned off promptly when no longer needed (McEwen et al., 2015). Usually, our physiologic responses increase as we encounter the stressor, and decrease to the normal state as it ends. This active process of adapting and maintaining stability through the production of mediators is called allostasis. After the mediators return to the normal level, we are back to our balanced stage and ready for the next challenge.
However, if the person stays stressed for too long, or the allostasis is inefficient, i.e., not turned off when not needed, this chronically increased allostasis can lead to disease. We call this allostatic load or overload.
Allostatic overload will causes that way too many “stress mediators” stay in the brain even after the stressful event, which would impair the stress-sensitive regions in the brain such as hippocampus, amygdala, and prefrontal cortex (McEwen and Akil, 2020). These regions are very important for us: the hippocampus is essential for our memory and learning; the amygdala is essential for emotion regulations, fear, and aggression; and the prefrontal cortex is in charge of our executive functions including planning and decision making. Overall, chronic stress can affect our ability to function in almost every aspect of our lives. (To learn in more detail about how chronic stress can negatively impact our body, please refer to blog posts such as https://psych-neuro.com/2020/02/26/how-chronic-stress-is-threatening-your-memory/, https://psych-neuro.com/2020/02/25/if-youre-looking-for-a-reason-to-sleep-here-it-is/, and https://psych-neuro.com/2020/02/24/take-a-load-off/.)
So what determines who will be more likely to be affected by chronic stress?
According to McEwen et al. (2015), it is encoded in our genes that whether we are resilient to chronic stress or not. Moreover, our early life experience determines to what extent our resiliences to chronic stress are determined by our “stress” genes. A person’s experience in their fetal development, early childhood, and adolescence can largely influence how they respond to stress, either enhancing their ability to handle stress in a healthy manner or making them vulnerable to stress-related disorders. For example, it has been found in animals that offsprings with less-attentive mothers appears to have worse stress-coping abilities.
But… those all seem like things that we are not able to change now. Does it mean that there is no hope?
NO! We can make some change!
McEwen et al. (2015) suggested that, although there is no going back in our development, we can have interventions that compensate for the adverse changes.
- Physical activities
Regular physical activities improve prefrontal cortex blood flow and thus enhance executive functions. Moreover, doing regular exercise, which consists of walking an hour a day, 5 out of 7 days a week, has been shown to increase the volume of hippocampus in previously sedentary adults.
* Quiz time! What brain functions is hippocampus related to? Memory and learning! *
- Intensive learning
Yes, learning has been shown to increase the volume of hippocampus too!
- Social integration, social support, and finding meaning and purpose in life
Guess what? These elements are extremely helpful in terms of helping us care for our mental health. They have been shown to help resist decline in physical and mental health and improve blood flow in prefrontal cortical blood flow in a similar manner to regular physical activities.
- Cognitive-behavioral therapies
Reach out to a therapist who can provide targeted emotional and cognitive therapies to help us repair our brain’s allostasis mechanism. Behavioral therapy that is tailored to individual needs can product volumetric changes in both prefrontal cortex and amygdala, which are important for improving executive functions and emotion regulations.
To sum up, to protect ourselves from allostatic overload, we would want to avoid being stressed for a long time, and take care of ourselves by exercising regularly, doing more intensive learning, building our social support and finding purpose in life. And, we can go to a therapist for help when we need it. Although it is unlikely for us to avoid stress in life, we can build our resilience to it and win against it.
References
McEwen B. S. (2006). Protective and damaging effects of stress mediators: central role of the brain. Dialogues in clinical neuroscience, 8(4), 367–381.
McEwen, B. S., & Akil, H. (2020). Revisiting the stress concept: Implications for affective disorders. The Journal of Neuroscience, 40(1), 12–21. https://doi.org/10.1523/JNEUROSCI.0733-19.2019
McEwen, B. S., Gray, J., & Nasca, C. (2015). Recognizing Resilience: Learning from the Effects of Stress on the Brain. Neurobiology of stress, 1, 1–11. https://doi.org/10.1016/j.ynstr.2014.09.001
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