Why do I always get sick on vacation?
Last updated September 3, 2026.
Two things at once: a real "let-down" pattern - a Dutch study of 1,893 people found about 3% report falling ill on weekends and holidays, clustering in the first vacation week - and plain exposure math. The proposed mechanism: when work pressure drops abruptly, stress hormones fall and immune function reshuffles, letting incubating infections surface. The math: planes, lost sleep, new microbes, and a body run down from the pre-trip crunch. The research is thin and recall-based - real but fuzzy. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What to do
- Taper, do not cliff: an easy first day or two cushions the hormone drop.
- Defend sleep through transit: jet lag is the vacation immune tax.
- Wash hands on travel days: airports and planes are the exposure peak.
- Get seen if: every break brings infections that run severe - frequency and severity beat the leisure-sickness story.
Related questions
- Can I fly with the flu?
- How do I sleep on a plane?
- How do I fix my sleep after jet lag?
- How long is a cold contagious?