Hormesis
concept · updated
Hormesis is the principle that a controlled dose of stress makes the body stronger by switching on repair and maintenance pathways. It’s the biological version of “shock the system to make it adapt” — the same logic that breaks hedonic adaptation in the mind.
The switches
From David Sinclair’s longevity work (source):
- AMPK — turn it up. Rises when you’re hungry or moving (low energy/ATP). Signals the body to build more mitochondria.
- mTOR — keep it low. Rises when you gorge on protein and sugar; blocks autophagy (cellular cleanup). Low mTOR = repair mode.
- Sirtuins + NAD. When the body senses scarcity or stress it makes NAD, fuel for sirtuins that handle DNA repair and epigenome stabilization. (Alcohol depletes NAD — see caffeine & sleep and nutrition.)
The operating idea: “treat your body so it thinks it’s under threat.”
The levers that pull the switches
- Fasting / calorie restriction — the cleanest AMPK/autophagy trigger; deep autophagy kicks in after ~3 days of fasting. See intermittent fasting and lose weight.
- Hard exercise / hypoxia — losing your breath turns on HIF-1α and mitohormesis: brief free-radical stress that results in more mitochondria. HIIT produces up to ~10× more growth hormone than steady-state (Head Strong). See strength training.
- Cold exposure — 30 seconds of cold to end a shower drives thermogenesis and brown fat (mitochondria-rich); depleting muscle glycogen signals more testosterone and growth hormone, lowers inflammation, triggers autophagy (Head Strong, Sinclair). Easier to build brown fat at middle age than old age.
- Heat / sauna (weaker evidence) — activates heat-shock proteins that refold proteins and build blood vessels; associated with ~20% lower cardiovascular mortality.
- Xenohormesis — plants stressed while growing make protective polyphenols (e.g. in red wine) that switch on our sirtuins; organic/stressed plants may carry more (nutrition).
The caveat
Much of this is Sinclair’s theory, not settled fact, and some of his specific supplement claims are contested — see supplements and the Resveratrol skepticism. The behavioral levers (fast, move hard, get cold) are the low-risk, well-supported part.
Related
- Intermittent fasting · Strength training for longevity · Nutrition for longevity · Supplements for longevity
Citations
- Lifespan (Talk at Google) — David Sinclair
- Critique of Sinclair’s longevity claims — Charles Brenner
- Head Strong — Dave Asprey
- Resveratrol skepticism — Brad Stanfield
tags: health longevity hormesis