# Cold exposure

Cold exposure is the deliberate use of cold air, water, or ice as a hormetic stressor. Think cold showers, ice baths, or cryotherapy. Acute cold triggers a release of noradrenaline and tightens your surface blood vessels. If it is intense enough, you start shivering to make heat; some protocols are designed to stay below shivering. It may switch on brown fat (brown adipose tissue), though how much that fires in humans varies a lot with the protocol and how you measure it. Reported effects include better cold tolerance and a subjective sense of alertness. But evidence for metabolic, immune, and longevity benefits in humans stays limited and mixed.

## Sources

- van Marken Lichtenbelt WD, Vanhommerig JW, Smulders NM, Drossaerts JM, Kemerink GJ, Bouvy ND, Schrauwen P, Teule GJ. (2009). Cold-activated brown adipose tissue in healthy men. New England Journal of Medicine. https://doi.org/10.1056/NEJMoa0808718
- van der Lans AA, Hoeks J, Brans B, et al.. (2013). Cold acclimation recruits human brown fat and increases nonshivering thermogenesis. Journal of Clinical Investigation. https://doi.org/10.1172/JCI68993

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_Canonical: https://longevity-austria.com/en/glossary/cold-exposure · Part of Longevity Cities · Updated 2026-06-22_