Environment

Cold exposure

Immediate effects on mood and alertness; weak data on fat loss and lifespan — a good habit, not a longevity tool.

Impact 1/52/5· Small human trialsEffort: a habit

First step today

Make the last 30 seconds of tomorrow's shower cold.

How

30–90 seconds cold at the end of a shower, or 2–3× a week 2–5 minutes in 10–15 °C water. Not within 4 hours after strength training (blunts hypertrophy).

Evidence

Søberg 2021 (n=8+8): winter swimmers had more active brown fat, but body weight did not differ. RCTs: dopamine +250% (Šrámek 2000), better mood; no mortality data.

Goals

Energy, fatigue

Sources

Søberg S et al. Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell Rep Med (2021) ↗

Last reviewed: 6 September 2026

This site is educational and does not replace medical advice. Start any supplement or drug only after consulting a doctor or pharmacist.