Mental exertion arguably falls under the rubric of stress. Problem is stress is inherently ambiguous and varies with individual perception such that it’s seemingly impossible to examine stress separate from our individual perception of it.
As Gailen D. Marshall explains (1),
‘Stress is a term often used to connote an adverse situation. Yet our use of the term stress derives from an engineering term that is used to reflect the impact of a situation (often called a stressor) on host homeostasis. It is best thought of as a psychophysiological process that is a product of both the appraisal of a given situation (either acutely or chronically over time) and the ability to cope with that situation. If the situation threatens harm, loss, or danger and/or the host-coping ability is deemed inadequate, the stress is termed distress. Most common uses of the term stress actually mean distress’
While thefield hasn’t made much headway into exactly how neuroendocrine functions impact immune health, it’s not surprising that stressful life events and perceived stress both influence immune function (2). Unsurprising then that this in turn could render an individual more susceptible to common infections such as cold or prolong their symptoms.
Problem with evaluating what appears to be quite a logical surmise is that there are few carefully controlled studies which thoroughly evaluate an individual’s psychological stress and then experimentally expose them to an infectious agent.
Having said that, a couple of such studies have indeed been done in the case of the common cold and the results showed that greater an individual’s recent experience of major stressful life events and higher their levels of perceived stress, greater their susceptibility to common cold and longer the duration of their symptoms.
- A 1991 study reported psychological stress enhanced susceptibility to the common cold (
- In this study, 394 healthy subjects completed questionnaires assessing their levels of psychological stress and were then given nasal drops containing one of five respiratory viruses (either rhino, respiratory syncytial or corona).
- 26 control subjects got saline drops. All were then quarantined and monitored for their symptoms.
- Authors analyzed the results controlling for age, sex, education, allergic status, weight, season, number of subjects housed together and virus-specific circulating antibody levels at baseline.
- Authors found both respiratory infection and its clinical symptoms correlated with an individual’s report of major stressful life events over the past year and were significantly increased with increasing levels of questionnaire-based psychological stress scores.
- The same first author reported similar results in a more recent 2015 study on 360 healthy adults (
- In this study, poorer an individual’s self-reported health, greater their susceptibility to developing clinical illness after being exposed to a common cold virus (rhinovirus).
- Again, these results were found independent of age, sex, race, circulating virus-specific antibody levels at baseline, weight, season, education and income.
1. Marshall, Gailen D. “Neuroendocrine mechanisms of immune dysregulation: applications to allergy and asthma.” Annals of Allergy, Asthma & Immunology 93.2 (2004): S11-S17.
2. Moynihan, Jan A., et al. “Stress and Immune Function in Humans: A Life‐Course Perspective.” The Wiley-Blackwell Handbook of Psychoneuroimmunology (2013): 251-265.
3. Cohen, Sheldon, David AJ Tyrrell, and Andrew P. Smith. “Psychological stress and susceptibility to the common cold.” New England journal of medicine 325.9 (1991): 606-612.
4. Cohen, Sheldon, Denise Janicki-Deverts, and William J. Doyle. “Self-rated health in healthy adults and susceptibility to the common cold.” Psychosomatic medicine 77.9 (2015): 959.