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Have you ever been so stressed, that you can’t sleep? How well can you cope with stressful situations?

My last two posts were about pain, movement (here), and training (and here). We briefly touched on stress as well and how it plays a part in pain. This post is all about psychological stress and why you should give it some thought.

Stress is everywhere. It impacts everyone and their health. I think the impact is underestimated in training and recovery.

What is stress?

Let’s get going by defining what we mean by stress. The American Psychological Association defines stress as “The physiological or psychological response to internal or external stressors.” (1)

The interesting part about stress is that a stressor doesn’t cause stress if your body doesn’t perceive it as such. It kind of sounds the same as what we talked about the perception of pain.

Stress response

Stress is always an interaction between a person and their environment.

A stress response happens when our body has to adapt to a stressor (2). This adaptation to threats keeps us alive (3). If our ancestor’s stress response didn’t fire when attacked by a predator, there’s a high chance they were in a lot of trouble. Although nowadays it’s not a predator but an email notification.

We’ll get a little technical now but if it’s not your thing, you can jump to the part about cortisol.

Two systems start their coordinated activation:

SAM system

Sympathetic-adrenal-medullary (SAM) system fires when we are suddenly frightened or under threat. SAM system’s effect is very rapid. In our brain, the amygdala and hypothalamus activate our autonomic nervous system (ANS), which in turn activates our internal organs. At the same time, our brain releases adrenaline which preps our body to respond. This cascade of events is also known as the fight-or-flight response. (2,3)

HPA axis

At the same time, another system is activated but it requires a longer stressor. Hypothalamic-pituitary-adrenal (HPA) axis is switched on when we perceive something to be stressful. (2,3)

It starts in our hypothalamus, releasing a hormone called corticotrophin-releasing factor (CRF). This travels in our blood to the pituitary gland, which stimulates the release of adrenocorticotrophic hormone (ACTH). This hormone in turn is transported to our adrenal gland. And there the stress hormone, you might have heard of, cortisol is produced. (2,3)

Cortisol

Cortisol has multiple roles. Some of the central functions we are interested in are the ability to increase access to energy stores, increase protein and fat mobilization, and decrease inflammation. (2,5)

Stress has a bad reputation but what is often forgotten is that it’s amazingly beneficial for our survival and performance.

Good and bad stress

Bruce McEwen was a neuroscientist who spent the bulk of his career focused on stress. I like his definitions of “good”, “tolerable”, and “toxic” stress:

“Good stress” is something we take a chance on. For example, nailing a work interview, an exam, or a presentation and feeling rewarded afterward.
“Tolerable stress” is when something bad happens but we can cope with it.
“Toxic stress” means when we meet problems and we don’t have the resources to deal with them.

Due to “toxic stress” our sleep might be affected, and we might adopt unhealthy behaviors or develop mental and physical health problems as a result of something called allostatic load. (4)

Allostasis and allostatic load

Allostasis is a term used to describe the adaptation process to acute stress to maintain our body’s homeostasis through change. Allostatic load is the cost our body pays for being forced to adapt to these stressful situations. (5,6)

For example, a person who has had a lot of toxic stress in their life can experience excessive allostatic load. The excessive allostatic load can cause “wear and tear” like cardiovascular diseases, obesity, diabetes, cancer, and other non-communicable diseases. For example, a person who’s lived in poverty has been shown to have an earlier decline in physical and mental function. (5,6)

I want to highlight that stress is not only bad. We need stress to adapt. It’s the situations when environmental challenges exceed our ability to cope (6).

In part II, we’ll cover resilience & coping, how stress affects performance & recovery, and also how it can mess up your gains after training. The last part is about how to apply all of this in practice.

Thanks for reading this far. I truly appreciate it.

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REFERENCES:

1. APA Dictionary of Psychology [Internet]. [cited 2022 May 2]. Available from: https://dictionary.apa.org/

2. O’Connor DB, Thayer JF, Vedhara K. Stress and Health: A Review of Psychobiological Processes. Annu Rev Psychol. 2021 Jan 4;72(1):663–88.

3. Russell G, Lightman S. The human stress response. Nat Rev Endocrinol. 2019 Sep;15(9):525–34.

4. McEwen BS. The good side of “stress”. Stress. 2019 Sep 3;22(5):524–5.

5. McEwen B. Allostasis and Allostatic Load Implications for Neuropsychopharmacology. Neuropsychopharmacology. 2000 Feb;22(2):108–24.

6. Guidi J, Lucente M, Sonino N, Fava GA. Allostatic Load and Its Impact on Health: A Systematic Review. Psychother Psychosom. 2021;90(1):11–27.

Stress and performance Part I