GLOSSARY

Personalized Hydration is person-centered hydration; the personalized label alone does not validate a device or product.

Fluid needs depend on body size, exercise duration and intensity, clothing, environment and access. A fixed prescription for everyone, or automatically adding water whenever fatigue appears, misses these differences. Records from comparable sessions, drinking, body-mass changes and gut tolerance guide adjustments. A plan for a hot endurance session does not automatically fit a short cool workout.

Thirst is an important water-regulating signal, influenced by environment, age, habit and recent drinking. Drinking to thirst is practical in many situations; flexible planning can help when access is restricted or losses are high. Neither ignoring thirst nor forcing large volumes replaces learning the individual's responses and training conditions. Thirst is useful information, not an infallible numerical measure of a deficit.

Availability, drink temperature, flavor and carrying arrangements affect actual intake. A plan that exists only on paper or upsets the stomach will not work as intended. Test bottles, aid stations and breaks during training. Palatability should support appropriate drinking rather than encourage uninterrupted intake beyond losses. Practical access and tolerance are part of the strategy, alongside the planned fluid quantity.