Why Do I Always Get Sick On Vacation?

Dec 14, 2020

Dr. Ashley Margeson

Dr. Ashley Margeson


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Have you ever wondered why, when you were studying for exams, that you always managed to get sick exactl 24-48 hours after your last exam finished? Or why, a few years later now, you manage to get sick after Christmas, Hanukkah, Vacation, March Break, Easter or any holiday/vacation you might choose to take?

Our cortisol response and immune levels have a lot to do with it.


Stress is thought to have an immunosuppressive impact on the immune system, mediated through cortisol. Thus, if someone is subjected to a certain stressor, their immune system would be temporarily “shocked”, and pathogens would have a relatively easier time entering and proliferating (growing) within the body. This would result in that person having a greater chance of getting “sick”. Although this theory explains how stress may affect our immune system, perhaps it’s not so simple. It doesn’t explain how for most people, it’s not until the stressor is removed that symptoms of the inflammatory response begin to manifest. Growing evidence is showing support for an alternative theory—one that suggests that inflammation is a result of cortisol dysregulation.

In fact, it is the removal of the stressor that tends to be the contributing factor to why we get sick during our “down time”.  When you are in a stressful situation, your  kidneys are constantly releasing cortisol, suppressing you immune cells (so you’d see no signs of the inflammatory response). Over the course of the stressor being present, your immune cells would constantly be receiving this anti-inflammatory signal, but what happened the stress was suddenly removed, cortisol levels suddenly dropped, and the anti-inflammatory signal went away?

The factors holding back your system from activating it’s full immune response also go away. 

Enter the runny nose, fatigue, sore throat and low grade fever.


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Anisman, H., Griffiths, J., Matheson, K., Ravindran, A., & Merali, Z. Posttraumatic stress symptoms and salivary cortisol levels. American Journal of Psychiatry. 2001. 158, 1509–1511.

Bauer, ME. Stress, glucocorticoids and ageing of the immune system. Stress. 2005 Mar;8(1):69-83.

Kaufmann I, et al. Stress doses of hydrocortisone in septic shock: beneficial effects on opsonization-dependent neutrophil functions. Intensive Care Med. 2007 Sep 29

Leonord, B. Stress, depression and the activation of the immune system. World J Biol Psychiatry. 2000 Jan;1(1):17-25.

Miller, G.E., Chen, E., & Zhou, E.S. (2007). If it goes up, must it come down? Chronic stress and the hypothalamic-pituitary-adrenocortical axis in humans. Psychological Bulletin, 133, 25-45

Prignet et al. 2004. Clinical review: Corticotherapy in sepsis. Critical Care, 2, 122-129.


Todays episode is sponsored by the Nova Scotia Government. Today I’m asking you, as part of our team of 971,000, to work to slow the spread of COVID-19. Online self-assessments are available HERE (and are SO easy to fill out and book a time for testing!) and anyone living in NS can now asymptomatically test to help slow the spread in our province.

Appointments are required for the testing asymptomatically and can be booked until the date listed on the NS Gov website by using the online assessment tooland choosing the asymptomatic option.



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