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In my first blog, the Stress Paradox, I talked in broad terms about stress and referenced some interesting studies that demonstrate that our relationship with stress is potentially more important than the stressful event itself, in determining any adverse health effects. In this blog I take a closer look at the fight or flight response and how it has earned its fearsome reputation.
Cortisol, together with adrenaline and noradrenaline, play a significant role in re-distributing the mind and body’s resources to tackle a perceived threat. Faced with a sabre-toothed tiger, for example, it’s likely you’ll be less worried about digestion and reproduction and more concerned with finding safety. Faced with a waring tribe, you’ll probably prefer to have your blood flow diverted to the muscles in your legs and arms ready for battle, rather than your intestine or… elsewhere. You have no doubt read about the link between chronic stress and erectile dysfunctional in men. There is also some evidence that it may affect fertility in women.
Cortisol also plays a significant role in suppressing the immune function and influencing levels of inflammation. Cortisol is generally thought of as an anti-inflammatory, but more recent evidence has demonstrated that it has both an anti and a pro-inflammatory effect across the brain and body. Evidence over the last decade has been mounting, demonstrating a causal link between the effects of psychological stress on the body's ability to regulate inflammation, which can promote the development and progression of disease. For example, we know that we are more likely to catch a cold, our wounds will heal more slowly, and cancer can spread more rapidly, when we experience chronic negative stress. More recent evidence is pointing to a causal link between increased inflammation and mental ill-health. The evidence substantiates the widely held view that our body was not designed to deal with long-term stressors.
Turning to the brain, both the prefrontal cortex and hippocampus are negatively impacted by the long-term release of stress hormones such as adrenaline and cortisol. The prefrontal cortex is responsible for executive functioning (logical, rational thinking), whilst the hippocampus is involved in memory consolidation and retrieval, amongst other things. Chronic stress has been shown to adversely impact the size and connectivity of both of these brain regions, significantly increasing the risk of mental ill-health. However, acute stress can be equally as debilitating, negatively impacting the effective functioning of the prefrontal cortex and also impairing the ability of the hippocampus to retrieve long-term memories. If you have ever found yourself struggling to remember salient facts while standing on stage in front of a microphone, you will now have a better idea as to why.
The impairment of the prefrontal cortex also results in us becoming far more impulsive and less able to think logically and rationally, much like the Hulk. There is evidence to suggest that our IQ takes a substantial hit when we’re under the influence of fight or flight, with several studies finding IQ can drop as much as 10-15 points, the equivalent of going a night without any sleep or being drunk. We’re also far less able to regulate our emotions and we experience far greater tunnel vision, which prevents us from seeing things clearly and rationally. The bottom line is that we are far from the best version of our self when under the influence of fight or flight, even more so when stress becomes chronic. We often make poorer decisions, adopt poorer behaviours and undermine our relationships with others, as a result.
Thinking back to the stress paradox in the first blog, it is now easier to understand why stressing about stress is harmful to health. Our stress response was only ever designed to be used in short bursts of up to 30-minutes, to escape an imminent threat to survival. When a zebra is chased by a lion, it either has its intestines ripped out from under it, as it tries in vain to escape, or it successfully outruns the lion and returns to graze peacefully with not a care in the world. Where humans appear to go wrong, compared to other mammals on the planet, is two-fold. Firstly, the vast majority of the threats that humans perceive today, do not actually pose a threat to our long-term survival. However, our brain interprets a perceived threat by triggering fight or flight, irrespective of whether our fear stems from a life-threatening sabre-toothed tiger or co-worker who rubs us up the wrong way.
Secondly, unlike a zebra who will merrily go back to grazing once a threat has passed, as humans, we have a tendency to replay the stressful event in our minds over and over again or take aversive action, such as drinking alcohol or taking drugs, to avoid those stressful thoughts. We know from research that rumination (replaying negative thoughts over and over in the mind) is strongly correlated with a significantly increased risk of mental ill-health, including anxiety and depression. Your brain, left to its own devices, has no way to differentiate between a bunch of neurons firing as a result of external stimuli in the present moment or because you happen to be replaying a past event in your head. Both scenarios result in the same pattern of neurons firing, which your brain will then interpret as if it is actually happening.
In my third and final blog next month, I will look at how you can positively change your relationship with stress, so that it works for you rather than against you.
Nick Bloy is a former lawyer and HR Business Partner with a Masters in Chemistry, who founded Wellbeing Republic in 2016, a consultancy that specialises exclusively in employee wellbeing. He is passionate about helping people to unleash their true potential and he believes that the key to peoples’ potential resides in understanding evolutionary biology and the neuroscience of the brain. He works as an executive coach and trainer, with organisations large and small to help individuals and the organisations they work for to thrive.
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