Stressful Stuff: Is Psychological Stress More Damaging Than We Realise? Eleanor Sherlock investigates the hidden connection between psychological stress and immune-related illnesses Stress is an unavoidable part of life. For something so draining, most people never imagine that those days of exam cramming or worrying about family might lead to long-lasting health consequences. At most, you might have noticed the pimples that seem to come up before that tight deadline, or the colds you come down with just after. Recently, however, the scientific world has begun to realise that, as abstract as psychological stress may be, it can have a very concrete influence on our physiology and the illnesses we may be at risk from. In particular, stress is thought to reprogram the immune system, increasing susceptibility to immune-related illnesses. What chemical changes accompany those unpleasant feelings of psychological stress? Stressful environmental triggers will activate a variety of brain centres that then mount a hormonal stress response, during which stress hormones are released from the adrenal glands. This process occurs in two stages. In the first stage,
noradrenaline and adrenaline are released, hormones that mediate the ‘fight-or-flight’ symptoms of stress, such as an increased heart rate. In the second, cortisol is released, a hormone that ensures the continued maintenance of the stress response. Noradrenaline, adrenaline, and cortisol exert their effects by binding their respective receptors on nearly all cells of the body. Binding leads to changes within the cell that prepares the body for a ‘fight-or-flight’ situation. Within the immune system, this leads to the activation and redistribution of immune cells from the lymph nodes into the bloodstream and to vulnerable areas such as the skin. This process is known as inflammation and helps prepare the body to fight potential infections, which may accompany the stressful environmental trigger. More specifically, noradrenaline and adrenaline stimulate inflammation, while cortisol has a more regulatory effect, helping to keep this inflammation from getting out of control and becoming damaging. This acute change in the immune system in response to stress is generally useful, protecting the body against infection in potentially dangerous situations. The issue arises when this stress response is chronically activated, as it is in certain stress-related conditions such as generalised anxiety disorder, or in long-term suffering. It is hypothesised that chronically elevated cortisol levels can lead to cortisol resistance — where the same level of cortisol no longer exerts an effective regulatory response. Subsequently, chronic inflammation ensues, where the pro-inflammatory effects of elevated noradrenaline and adrenaline are no longer controlled. Chronic Inflammation Can Only Be Bad News | Chronic inflammation underlies a range of seemingly unrelated illnesses. The ability of psychological stress to induce and exacerbate this condition means that it is a serious health risk which is only beginning to be taken seriously. For example, chronic psychological stress has been observed to increase susceptibility to certain infections. Initial work has suggested that infection rates of the common cold were higher in individuals exposed to higher levels of psychological stress. Recent work has also indicated that individuals with stress-related disorders such as anxiety or PTSD are at a higher risk of contracting life-threatening infections. This association was mainly observed for infections which involve some kind of overreaction of the immune system, indicating that chronic inflammation could be the underlying
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Stressful Stuff
Lent 2021
