Cold Water Immersion: Simultaneous Assessment of Cerebral Oxygenation, Vascular Function, and Thermoregulatory Responses

Initial exposure to CWI induced a cold shock response with a 43% increase in tidal volume, without a corresponding increase in respiratory rate. This suggested a potential, intuitive, cold-mitigation strategy in cold naïve participants. In addition, the O2Hb responses indicated a short-lived, cold-induced mismatch between cerebral oxygen demand and supply. The increase in cerebral oxygenation reflects a cold-induced increase in cerebral blood flow to prevent localized temperature drops, along with elevated counter-current vascularization and metabolic heat generation.