This session explores the physiology of hydration through an integrated lens—examining how carbohydrate, sodium, flavor, and fluid interact to influence intake, absorption, retention, and performance. We’ll review current research on fluid balance, osmotic drivers, and palatability, highlighting mechanisms that underpin voluntary intake and thermoregulation. Attendees will gain insight into individualized strategies, including sweat profiling and timing approaches, to optimize euhydration and mitigate performance decrements associated with >2% body-mass loss. Practical applications will be linked to laboratory- and field-based research, ensuring translation from bench to field. This pre-conference equips you with evidence-based tools to support athlete hydration across diverse environments and sporting contexts.