A common sign of dehydration during exercise is the sensation of excessive thirst, accompanied by a dry mouth. Individuals might also experience decreased energy levels or fatigue, which can significantly impair performance. In more severe cases, symptoms like dizziness, confusion, or dark-colored urine may occur. It's critical for athletes and exercise enthusiasts to monitor hydration levels closely, particularly during intense workouts and in hot climates, to maintain optimal performance and health while preventing complications associated with dehydration.