Hydration is essential for teenage girls during exercise to maintain proper fluid balance, regulate body temperature, and support overall performance and health. Dehydration can impair cognitive function, decrease coordination, and increase the risk of heat-related illnesses, all of which can negatively impact athletic performance. Encourage regular fluid intake before, during, and after exercise, and emphasize the importance of listening to your body’s thirst cues and staying adequately hydrated throughout the day.