Hydration is closely linked to physical endurance, as adequate fluid levels are necessary for maintaining thermoregulation, preventing fatigue, and optimizing performance. Dehydration can lead to decreased blood volume, affecting cardiovascular function and reducing the body's ability to deliver oxygen and nutrients to muscles. Even mild dehydration (1-2% of body weight) can impair endurance, performance, and cognitive function. Drinking water and electrolyte-replenishing fluids before, during, and after exercise is vital for sustaining endurance, especially in prolonged or intense training sessions.