Hydration directly influences energy levels during physical exertion. Adequate fluid intake is vital for maintaining optimal physiological functions, including thermoregulation, nutrient transport, and muscle function. Dehydration can lead to fatigue, decreased endurance, and impaired strength, negatively affecting performance. Regular hydration before, during, and after exercise helps sustain energy levels and reduce the risk of heat-related illnesses. Athletes, in particular, should monitor their hydration status to ensure peak performance, especially in high-intensity or prolonged training sessions.