The Neuroscience of Being an Ars*hole Under Stress

I recently did a podcast interview on the link between brain health and mental wellbeing, During the interview I confess that when I’m stressed I can be a bit of an ars*hole. Appreciated, not ideal language on a podcast, however in talking with others (and witnessing the effect stress has on personalities), I know I’m not the only one for whom stress can open the door for our not-so-best-selves to run the show.
But why does this happen, at a physiological level? What effect does chronic stress have on our brain and its functions that can make us short-tempered, irritable or react like an ars*hole?
Not to take away from personal responsibility and accountability whatsoever BUT, the link between chronic stress and mood changes such as irritability, moodiness, and short temper is deeply rooted in neuroscience.
Here are just a few of the ways why being under stress long term can affect us physiologically, influencing our response and reactions:
1. Amygdala Overactivation
The amygdala is a small, almond-shaped structure deep in your brain that plays a big role in how you feel and react to the world around you. Think of it as your brain's ‘emotion centre.’
What happens |
The effect |
Chronic stress sensitizes the amygdala, making it hyperactive. |
The amygdala becomes more reactive to perceived threats or frustrations, leading to exaggerated emotional responses like anger or irritation. |
2. Prefrontal Cortex Suppression
Your prefrontal cortex is located just behind your forehead and is one of the most advanced and ‘human’ parts of the brain, responsible for decision-making, self-control, emotional regulation and complex thinking.
What happens |
The effect |
Chronic stress and high cortisol levels suppresses your prefrontal cortex. It’s like stress ‘turns down the volume’ on this part of the brain. |
This suppression reduces your ability to ‘think before reacting,’ leading to a short temper or snappy behaviour. It can also cause forgetfulness when stressed for a long time
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3. Hyperactivation of the Hypothalamic-Pituitary-Adrenal (HPA) Axis
Your HPA axis is a communication network in your body, controlling how your body reacts to stress.
What happens |
The effect |
Chronic stress leads to the overactivation of the HPA axis, and because the HPA axis is a key stress-response system, this results in the release of excessive levels of the stress hormone, cortisol. |
Persistently high cortisol levels dysregulate the brain's emotional centers, particularly the amygdala and the prefrontal cortex. This imbalance can increase emotional reactivity, making you more prone to irritability and snapping at others. |
4. Inflammation in the Brain
(We talk a lot about neuro-inflammation at The Vitalogy Project, check out some of our articles on our site on this.)
What happens |
The effect |
Chronic stress triggers low-grade neuroinflammation. Elevated cytokines (inflammatory molecules) can disrupt brain function, especially in mood-regulating areas like the hippocampus and prefrontal cortex. |
This inflammation contributes to feelings of irritability, mood swings, and emotional instability.
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5. Sleep Disruption
Your body has a natural rhythm for sleep and wakefulness whereby ideally, cortisol levels are high in the morning (to help you wake up and feel alert) and then low by nighttime (so you can relax and fall asleep).
What happens |
The effect |
Chronic stress keeps cortisol levels too high at night, making it harder to wind down and fall asleep. Elevated cortisol levels also disrupt production of melatonin (the hormone that makes you sleepy). |
Reduction in deep sleep, waking too early and/or difficulty falling back to sleep. A lack of quality restorative sleep affects emotional regulation, and amplifies irritability, mood swings, and a tendency to overreact.
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This information isn’t intended to excuse our behaviour under stress - the intention is to illustrate that there are multiple, interlinking, overlapping exacerbating factors at play at a physiological level. And most importantly – that you can do something about it to support the health of your brain now, in order to mitigate this physiologically impacting the health of our brains into the future.
Stress creates a cycle—when we’re overwhelmed, we react more emotionally, which makes situations feel even more stressful, keeping us stuck in a loop. But we can break this cycle by strengthening our brain’s ability to handle stress.
Like most things, awareness is key. So when you snap at someone, you overreact, or you’re struggling to rationalise with a racing anxious mind, say thank you to these warning signs because now you know that when this happens, healthy functioning in your brain is starting to go awry and been aware of those signs allows you to do something about it.
By nourishing our nervous system with the right support, such as exercise, prioritising sleep, deep breathing, mediation, mindfulness practices, nutritious foods and targeted nutritional supplements, we can help balance our stress response. Ingredients in supplements that support calmness and resilience can help keep cortisol in check, allowing the prefrontal cortex (the rational, decision-making part of the brain) to stay in charge, rather than the amygdala (the brain’s emotional alarm system).
Over time, this means we perceive challenges differently—instead of reacting with frustration or anxiety, we stay clear-headed and adaptable. By supporting our brain now, we set ourselves up for a calmer, more resilient future, where stress no longer controls us.
If this article resonates with you, then you and I are the reason I formulated our Calm & Relax supplement using the beautifully complementary ingredients of L-theanine and Holy Basil to help all the stressy folk out there!
L-Theanine calms the mind, enhancing mood-regulating neurotransmitters, and reducing the physiological effects of stress, L-theanine can directly address the irritability, mood swings, and the short temper associated with chronic stress. It's especially valuable because it achieves this without sedation, allowing you to remain alert and functional throughout the day. Within about 15-20 mins my mind is calmer and I’m able to focus which is brilliant.
And then coupled with Holy Basil’s adaptogenic (which means it supports our bodies and minds to adapt to stress), neuro-protective, and calming properties make it an effective natural remedy for managing stress-related mood changes, irritability, and emotional instability. It works holistically by addressing the physiological and psychological roots of stress while promoting overall resilience and well-being.
I take Calm & Relax everyday, morning and night, and I’m proud to have far fewer ‘ars*hole’ moments. It’s certainly empowering to stay in control and able to ride life’s stress waves instead of being cast adrift by them.
And here’s the link to the podcast mentioned at the start of this article if you’d like to take a listen :)
Megan