Effects of Probiotics and Nutritional Status on Exercise-Induced Symptoms, and Endurance Performance in Ultra-Endurance Athletes

Ultra-endurance athletes have been commonly endured extreme conditions during races and training sessions, resulting in exercise-associated clinical symptoms, including gastrointestinal symptoms, dehydration, and elevated oxidative stress. Although these alterations adversely affect sports performance and well-being, there is no certain treatment or consensus on alleviating the exercise-associated clinical symptoms in ultra-endurance athletes. The objective of this study is to determine the effects of oral rehydration salts supplemented with Lactobacillus Rhamnosus GG on exercise-induced gastrointestinal problems, dehydration and oxidative stress in ultra-endurance athletes. Additionally, we aimed to assess the exercise-induced alterations in oxidative stress determined by applying an acute strenuous exercise protocol ((a cycle ergometer (45 min at 65%VO2max) immediately followed by a treadmill test (75% VO2max to exhaustion)) before and after the supplementation period.