https://www.nestacertified.com/sports-nutrition-training-course/ This video is one which is included in your NESTA Sports Nutrition Specialist Certification. Water is essential to maintain blood volume, regulate body temperature and allow muscle contractions to take place. During exercise, the main way the body maintains optimal body temperature is by sweating. Drinking fluid during exercise is necessary to replace fluids lost in sweat. Hydration Tips for Better Athletic Performance. Not only is eating the right types of foods extremely important for your athletic performance, but drinking enough fluids is also essential for optimal performance. Staying hydrated enables your body to provide adequate circulation to both your muscles and body surface. Not only is eating the right types of foods extremely important for your athletic performance, but drinking enough fluids is also essential for optimal performance. Staying hydrated enables your body to provide adequate circulation to both your muscles and body surface. A mere 1 percent dehydration level will hinder your athletic performance and health. Signs of dehydration are fatigue, headache, light-headedness, dry mouth and dark-colored urine.