RT null T1 Compositional Aspects of Beverages Designed to Promote Hydration Before, During, and After Exercise: Concepts Revisited A1 Pérez Castillo, Íñigo M. A1 Williams, Jennifer A. A1 López Chicharro, José A1 Mihic, Niko A1 Rueda, Ricardo A1 Bouzamondo, Hakim A1 Horswill, Craig A. AB Hypohydration can impair aerobic performance and deteriorate cognitive function during exercise. To minimize hypohydration, athletes are recommended to commence exercise at least euhydrated, ingest fluids containing sodium during long-duration and/or high-intensity exercise to prevent body mass loss over 2% and maintain elevated plasma osmolality, and rapidly restore and retain fluid and electrolyte homeostasis before a second exercise session. To achieve these goals, the compositions of the fluids consumed are key; however, it remains unclear what can be considered an optimal formulation for a hydration beverage in different settings. While carbohydrate–electrolyte solutions such as sports drinks have been extensively explored as a source of carbohydrates to meet fuel demands during intense and long-duration exercise, these formulas might not be ideal in situations where fluid and electrolyte balance is impaired, such as practicing exercise in the heat. Alternately, hypotonic compositions consisting of moderate to high levels of electrolytes (i.e., ≥45 mmol/L), mainly sodium, combined with low amounts of carbohydrates (i.e., <6%) might be useful to accelerate intestinal water absorption, maintain plasma volume and osmolality during exercise, and improve fluid retention during recovery. Future studies should compare hypotonic formulas and sports drinks in different exercise settings, evaluating different levels of sodium and/or other electrolytes, blends of carbohydrates, and novel ingredients for addressing hydration and rehydration before, during, and after exercise. PB Multidisciplinary Digital Publishing Institute (MDPI) SN 2072-6643 YR 2023 FD 2023-12-20 LK https://hdl.handle.net/20.500.14352/121110 UL https://hdl.handle.net/20.500.14352/121110 LA eng NO Pérez-Castillo, Í. M., Williams, J. A., López-Chicharro, J., Mihic, N., Rueda, R., Bouzamondo, H., & Horswill, C. A. (2024). Compositional Aspects of Beverages Designed to Promote Hydration Before, During, and After Exercise: Concepts Revisited [Review of Compositional Aspects of Beverages Designed to Promote Hydration Before, During, and After Exercise: Concepts Revisited]. Nutrients, 16(1). Multidisciplinary Digital Publishing Institute (MDPI). https://doi.org/10.3390/NU16010017 DS Docta Complutense RD 14 jun 2025