Why is hydration crucial before, during, and after exercise?

Hydration is vital for supporting optimal physiological function during exercise, as it plays several key roles in maintaining performance and health. Water comprises a significant portion of our body and is involved in various physiological processes, including temperature regulation, nutrient transport, and waste removal.

Before exercise, adequate hydration ensures that the body is primed for performance, helping to maintain core temperature and joint lubrication. During exercise, it prevents dehydration, which can impair performance, reduce endurance, and impair cognitive functions. After exercising, hydration is equally important to aid recovery, as it helps to replenish fluids lost through sweat, supports metabolism, and protects against muscle soreness and fatigue.

While preventing fatigue is an important outcome of hydration, the broader context of supporting all physiological functions makes the statement about optimal physiological function the most comprehensive and therefore the correct choice. The options regarding muscle mass and bone density relate to different aspects of health and fitness that are not directly tied to hydration in the immediate scope of exercise performance.