Why do I get sick when I am run down?
Last updated September 3, 2026.
Because "run down" is a real immunological state: in a landmark NEJM experiment, stressed volunteers deliberately exposed to respiratory viruses got infected in a dose-response pattern - clinical colds climbed from about 27% to 47% as stress rose. The risk came from more infection, not just more symptoms, and was not explained by sleep, diet, or white-cell counts. Chronic stress keeps cortisol and sympathetic signals high, thinning defenses exactly where respiratory viruses land. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What to do
- Plan for the post-crunch dip: the week after the deadline is when defenses run thinnest.
- Protect sleep first: it is the recovery variable with the strongest immune evidence.
- Lower exposure when run down: crowded indoor air right after a crunch is the bad combination.
- Get seen if: you catch everything, or infections run long and severe - frequent-severe is an immune workup, not a stress story.
Related questions
- How long is a cold contagious?
- Can I go to work with a cold?
- Can you get antibiotics for a cold?
- Can you get rid of a cold in 24 hours?