Dehydration negatively affects physical performance by impairing various physiological functions. It can lead to reduced endurance, increased fatigue, and decreased strength, affecting athletic performance and daily activities. Even mild dehydration alters thermoregulation, cardiovascular function, and overall energy levels. Symptoms can include dizziness, headache, and decreased motivation. Staying adequately hydrated before, during, and after exercise is crucial for maintaining optimal performance, promoting recovery, and minimizing the risk of heat-related illnesses.