Valerie is a high school cross country athlete seeking help to develop a hydration plan. She believes her times this season have not come down because she is experiencing dehydration during practices and at meets. She is working to improve her pre-exercise hydration status and is confused about which fluid sources are best to promote optimal hydration. She has tried water, fruit juice, Gatorade, milk, and even one of the new energy drinks. She isn’t sure which drink is the best choice for her. Please discuss the possible advantages and disadvantages of each of these beverages keeping in mind she is most interested in using this beverage for pre-exercise hydration.