This tool is useful for assessment of fluid losses during exercise based on changes in body weight. Sweat rate varies depending on factors such as environmental conditions, exercise type, exercise intensity, and clothing worn. Therefore, when used repeatedly for the same athlete this tool can be used to assess sweat rate in varying conditions. For the most accurate results, both fluid and food intake should be included in the calculations, along with any urine losses occurring during the test session. This tool will provide the practitioner with information to help the athlete develop a hydration strategy during exercise.