Chronic dehydration can severely impact physical performance by reducing endurance, strength, and overall energy levels. It affects the body's ability to regulate temperature, leading to increased fatigue and a higher risk of heat-related illnesses. Dehydration can impair cognitive functions as well, affecting decision-making and reaction times. Athletes especially need to maintain proper hydration levels, as even a slight decrease in body water can compromise performance. Thus, ensuring adequate fluid intake is essential for optimal physical functioning.