Sometimes it can be hard to juggle the increasingly demanding tasks of a normal day: a hectic day at work, attending to a house, enjoying something of a social life…Getting to the end of the day without going crazy and/or feeling sick feels like an odisey in those stress dominated periods. Since I am myself in the midst of one of such periods, I thought to dive into the topic of the interaction of stress and the immune system because…well, you have to know your enemy, right?
First of all, stress is something natural -you know one of those things that eco-bio-cool people like so much these days- which in this case means it is an evolutionary reaction in response to a potential agression (predator or accident) that can also be triggered by the immune system in case of an infection of after a vaccination. There are two types: the acute stress response is short -minutes to hours- and corresponds to the typical fight-or-flight response; chronic stress, on the other hand is more problematic since it involves a deregulation of the immune system and can last from several hours a day to weeks or even months.
What goes on in your body after your brain interprets something as a menace? And that can be a real menace, like a car aiming right at you, or your boss asking for something to be done tomorrow. First, the amigdala and the hippothalamus get activated and there’s an adrenaline discharge that subsequently produces cortisol release. This cortisol is the main mediator of all bodily stress responses: increase blood pressure, movilization of energy sources and increase in blood sugar concentration, among others. All these changes maximise energy production to prepare the body for the fight-or-flight response.
When it comes to the immune system, things get complicated. There are plenty of factors involved like age, previous health state, individual genetics…However, for acute stress it seems there’s a beneficial effect on the immune response. However, when stress becomes chronic, the immune response becomes deregulated or even inhibited. For instance, there’s an association between chronic stress and an inhibited skin cellular immune response, also consistant with the development of skin diseases of autoimmune origin like alopeacia areata.
We could see this interaction between stress and immune system as a double edged sword. Under normal circumstances, that is acute (short duration) stress, the immune system becomes strengthened whereas it becomes deprived when the stress response also gets out of hand. A possible explanation for this change in behaviour could be of an endocrinological nature: the balance of hormones and circulating neurotransmites that modulate the expression of citokines and cortisol specific receptors in leukocites that would result in the overproduction of certain cell types and factors that could instead of assist us act as a trojan horse against us (autoimmunity).
One type of chronic stress that has already been shown to affect the production of NK cells, citokines and the humoral response after vaccination is: chronic lack of sleep. Now, who is free of charge?
We are all different, and of course that also goes for stress. There are plenty of biological, social and psycological factors that affect the magnitude and duration of a stress response. To this day there’s little we can do about the biology part, but thankfully we can still do a lot on the other sides. There are a plethora of possibilities when it comes to fight stress: from doing sports, to yoga, meditation, reading or just a good night of sleep. Although honestly, I could think about a couple others I haven’t seen ever reflected in any publication…Anyhoo, most important is to teach our brain to stop identifying possible threats where there aren’t. Not being able to find your boarding gate an hour before departure is NOT a life or death situation: don’t panic and don’t stress (not my case, but tell my parents)
To sum up: there are still a number of question marks to fill in the complex relationship between stress and the immune system but one thing is clear: stress -in the long run- is not good for anyone except for pathogens, and those don’t count. So please, take a deep breath and repeat with me:
The effect of stress on the defense system. D Dragoş and MD Tănăsescu. J Med Life. 2010 February 15; 3(1): 10–18.
Psychological stress and immunoprotection versus immunopathology in the skin. Firdaus S. Dhabhar. Clinics in Dermatology Volume 31, Issue 1, January–February 2013, Pages 18–30