SPOILER ALERT! Stress is not necessarily bad. Stress can relieve pain through the release of opioids and even numb it The brain and the body evolve from a stressful experience, because they retain the information to be able to better handle it the next time But prolonged stress/chronic stress results in low-grade inflammation, which in turn causes physical and psychological harm.
Stress is defined as the organism’s attempt to adapt to any change brought on by physical or psychological pressure upon it. In other words, it represents a deviation from homeostasis (i.e., stability within biological systems), suggesting that it is not necessarily a destructive phenomenon.
For example, research shows that after a stressful experience, the body retains some aspects of the defensive response, effectively strengthening it against future similar stressors. This makes it a crucial player in physical and psychological growth and development. Therefore, understanding how stress elicits those changes is necessary to be able to harness its therapeutic potential.
Control over a stressor reduces its negative impact
Notably, the predictability and degree of control over a particular stressor not only affect how the brain is going to respond to it, but it also moderates the level of anxiety. Thus, controllable stress reduces its harmful effects.
For example, several studies indicate that the brain’s reward system (i.e., the ‘feel good system in the brain that is activated when you eat or have sex, for example) is activated in the presence of familiar stressors, which has the effect of lowering stress-induced anxiety.
It is attributed to the fact that familiar stressors enable the brain to quickly generate a response in anticipation of the impact that the stressor could have on the self.
Stress affects the immune system
Similarly, the immune system is also recruited during stress to cope with exposure to pathogens and tissue damage; however its activity depends on the type of stress. Specifically, acute stress is thought to magnify the immune response, while chronic stress suppresses it. This explains why chronically stressed individuals frequently get sick from infections like the flu or the common cold.
Furthermore, prolonged stress leads to low-grade inflammation, resulting in physical and psychological problems. For example, low-grade inflammation has been associated with irritable bowel syndrome. Hypertension is another condition triggered by stress that has a strong immune component.
By contrast, modulation of the immune response can have beneficial effects, particularly on pain perception. For example, less severe stress has analgesic effects on the body (i.e., relieves pain) through recruitment of the natural opioid system, which in turn elicits pain relief. Even severe stress has the potential to numb pain through activation of other pain-inhibitory mechanisms.
Haykin H, Rolls A. The neuroimmune response during stress: A physiological perspective. Immunity. 2021 Sep 14;54(9):1933-1947. doi: 10.1016/j.immuni.2021.08.023. PMID: 34525336.