Common signs of dehydration include thirst, dry mouth, fatigue, and reduced urine output. Early symptoms may also involve dizziness, headaches, and confusion. Severe dehydration can lead to more serious conditions, such as rapid heartbeat, lethargy, and fainting. It’s crucial to monitor hydration, particularly during intense physical activity or hot weather conditions. Recognizing these signs early can prompt individuals to increase fluid intake, thus preventing potential health complications associated with severe dehydration, such as kidney damage or heat-related illnesses.