From muscle recovery to mood elevation, cold immersion activates ancient survival pathways — and your genes may shape how you respond. Highlights Effect Impact Key Insight Muscle recovery Reduces soreness and inflammation by 20–30% Vasoconstriction limits swelling and tissue damage Mood and alertness Norepinephrine surges by up to 200–300% Enhances focus, energy, and well-being Metabolic activation Stimulates brown fat and thermogenesis Increases calorie burn and insulin sens