Heat shock proteins are a family of conserved chaperones (HSP60, HSP70, HSP90, etc.) that maintain proper protein folding and rescue misfolded proteins under stress.
Mechanism — Acute heat (sauna), exercise, hypoxia, and oxidative stress upregulate HSP expression. Protect cells against subsequent insult — the hormetic mechanism. Decline with age contributes to protein-misfolding diseases.
Use case — Induce via sauna (4x/week, 20+ min at 80-100°C), high-intensity exercise, and brief heat exposure. The Finnish sauna data is the cleanest population-level case for thermal hormesis.
Caveats — Cardiovascular precautions apply — don't sauna with poorly controlled BP or arrhythmias. Combine sauna with cold plunge cautiously — alternating thermal stress is a real load.