1. A marine biochemist in Marseille told me: “Seawater isn’t water — it’s a liquid nervous system reset.” He showed blood tests from volunteers who swam for eight minutes: cortisol dropped by 32% while vagus nerve activity spiked. “It mimics the body’s safety signal,” he said — the same response infants get when held to a parent’s chest. 2. The second effect is ion exchange. He placed two vials on his desk: one with sweat, one with seawater. “They’re almost identical,” he said. Magnesium, sodium