For how we live.
For acute ankle sprains, a review found only two poor trials and no clear benefit from ice. For sore muscles, cold-water immersion helps modestly. For low-back pain, a heat wrap has the best support.
For heat exhaustion, rest and shade usually suffice. For heat stroke, a meta-analysis of 63 studies found immersion in cold water cooled the body faster than anything passive — the intervention the evidence agrees on.
A 2025 meta-analysis found cold-water immersion cut stress 12 hours later, but not immediately — and its effect on immunity and mood did not hold up.
A pooled analysis of 30 randomized trials finds cold-water immersion reduces muscle damage markers and soreness, but showed no benefit for restoring strength.
Three UK studies of 1,907 sauna users point to social identity and ritual. Meanwhile a physiology paper shows a standard vascular measurement is confounded by heating itself.