Signs of dehydration include thirst, dry mouth, decreased urine output, and darker urine color. Other symptoms may be fatigue, dizziness, and dry skin. Severe dehydration can result in rapid heartbeat and confusion. Recognizing these signs is vital for prompt rehydration, especially during physical activities or in hot weather conditions. Individuals should pay attention to their body's signals and maintain adequate fluid intake to support overall health and prevent dehydration-related complications.