Under Pressure: Exploring the Brain's Response to Stress
By Nazanin Sz
As people living in the 21st century, it’s not uncommon for feelings of stress to be present in our everyday lives, but these feelings can go beyond day-to-day stressors and create long-lasting changes in brain function and wellness.
The National Institute of Mental Health defines stress as “the brain’s response to any demand”. Although we typically use the term stress with a negative connotation, not all stress is bad. Stress is a natural function of the human body and can be pathological depending on its intensity, duration, and treatment.
The brain is the central organ of stress that perceives which external sources are threatening and which are not to control the behavioural and physiological responses to a stressor. Our brains can provide an adaptation to stress but can also become imbalanced when it is overused and dysregulated. For example, studies in humans and animals show that stress can affect brain functions negatively by interfering with cognition, attention, and memory according to Dr. Kerry Ressler, professor of psychiatry at Harvard Medical School.
Stress causes the release of a cascade of hormones in the body such as cortisol (typically called the stress hormone), epinephrine, and norepinephrine. These hormones cause a physiological response characterized by increased blood pressure and heart rate, heightened senses, and adrenaline. This response is referred to as the stress response or the flight-or-fight response. When the stressor withdraws, hormone levels return to pre-stress levels. Acute stressors can be beneficial by causing a brief release of these hormones which can help improve motivation, the ability to focus, and performance. From an evolutionary perspective, this makes sense. Running or fighting a predator requires a short-term increase in these skills.
However, persistent or chronic stress can rewire the brain and have significant harmful effects on the brain and body. The build-up of cortisol in the brain from chronic stress interferes with long-term memory, attention, and executive functions that allow you to plan, organize, problem solve, engage in flexible thinking, and control impulses. Stress can even kill brain cells and reduce the size of the brain, especially the prefrontal cortex which is responsible for memory and learning. On the other hand, stress increases the size of the amygdala (an area of the brain that controls emotional processing) which makes the brain more receptive to stress. As a result, a vicious cycle is created where stress makes a brain more predisposed to constant stress.
As you can imagine, it’s very important to mitigate stress since the damaging effects of stress can be modifiable. Activities like exercise, good-quality sleep, and meditation can combat stress’ wear-and-tear effects on the brain regardless of age. So next time you start showing symptoms of stress like anxiety or nervousness, take these measures to not only feel better, but to promote a healthy and well-functioning brain. And consider being proactive by creating some healthy coping habits that are well engrained before a stressful experience presents itself!
Some helpful resources:
https://www.heretohelp.bc.ca/infosheet/stress
https://www.anxietycanada.com/
https://www.therapistaid.com/therapy-guide/stress-management-guide
Sources:
https://www.nimh.nih.gov/health/publications/so-stressed-out-fact-sheet
https://www.health.harvard.edu/mind-and-mood/protect-your-brain-from-stress
https://www.tuw.edu/health/how-stress-affects-the-brain/
