People often talk about stress and feeling stressed out. The combination of multiple work, family, and other commitments can start to feel like they’re crushing us.
So what exactly is stress? It occurs when strain is placed on the body in a way that disrupts its normal balance and functioning. The source can be internal or external, and it can be exerted psychologically or physiologically.
Part of the initial response comes from the activation of the sympathetic nervous system, i.e. the fight or flight response. This involves the release of the hormones epinephrine and norepinephrine.
The HPA Axis
The hypothalamic-pituitary-adrenal (HPA) axis is another pathway used by the brain to initiate the stress response. The hypothalamus, which acts as a control centre, can be triggered by the amygdala. The hypothalamus then sends a signal to the pituitary gland to release ACTH (adrenocorticotropic hormone), which then stimulates the adrenal glands to release the hormone cortisol. In the short-term, cortisol prepares your body to respond to the stressor, but longer-term dysregulation of the the HPA axis can have a negative effect.
In the short term, stress boosts energy levels and sharpens your senses. Stored sugar in the form of glycogen is released from the liver to fuel your reaction to the stressor. Your heart is pumping, and your airways expand to bring in maximum oxygen. Energy is diverted away from resting functions like digestion and reproductive system function. The hormone rush causes your memory to focus on stressor-related input, leaving less capacity to encode non-stress-related information into memory.
Chronic stress can contribute to or worsen a number of health conditions, and can keep the HPA axis persistently hyperactivated. Changes in heart rate and blood pressure can occur, and there is an increased risk for heart disease and diabetes. As the body becomes exhausted by the ongoing stress response, the immune system weakens.
The gastrointestinal system can be affected, which can be particularly problematic for people with irritable bowel system (IBS) or inflammatory bowel disease (like Crohn’s and ulcerative colitis). Depression and some other mental illnesses appear to have a link to inflammation, although the nature of that link is still being explored.
Reacting to stressors
There are four aspects of a stressor that result in the release of stress hormones:
- Threat to the ego
- Sense of control
The acronym for this is, suitably enough, NUTS. The novelty and unpredictability seem obvious enough, but the threats to the ego and sense of control dig a little deeper. For me, lack of control is huge. Not that I’m necessarily a controlling person, but having no control sends me cowering into my cave.
One theory proposed two types of stress: eustress and distress. Eustress is adaptive and helps us to function better. Distress is persistent and does not respond to coping strategies. And what would the opposite of stress be? While relaxation might seem like the obvious answer, resilience is actually a more fitting.
What I find fascinating is what a great example this is of the interconnectedness between mind and body. For me, at least, stress feels very mental with a side of physical, but it’s actually the body that’s really kicking it into high gear.
Chronic mental illness stops being novel pretty quickly, but it starts to develop a predictable unpredictability Threat to the ego? Check. Loss of control? Double check.
How does stress affect you?
You can find the rest of the what is… series in the Psychology Corner.
- American Psychological Association
- Centre for Studies on Human Stress
- Harvard Health Publishing
The COVID-19/Mental Health Coping Toolkit page has a wide range of resources to support better mental health and wellbeing.