1. Introduction
OXIDATIVE STRESS, CONTRACTION
These authors contributed equally to this work.This study investigated the acute effects of natural antioxidants, derived from yeast fermentation containing glutathione and dietary vitamin C supplementation, on metabolic function, skeletal muscle oxygenation, cardiac function, and antioxidant function during submaximal exercise in middle-aged triathlon athletes. Twelve participants (aged 49.42 ± 5.9 years) completed 90 min submaximal cycling trials corresponding to 70% maximal oxygen uptake with either vitamin C and glutathione (VitC+Glu), vitamin C (VitC), glutathione (Glu) supplementation, or placebo. Metabolic function (minute ventilation, oxygen uptake, carbon dioxide output [VCOOxidative stress occurs when the production of reactive oxygen species (ROS) exceeds the ability of the body’s defense system to eliminate them. During exercise, the body increases its oxygen consumption to generate energy for muscle contraction. This increase in oxygen consumption can lead to the generation of ROS, such as superoxide, hydrogen peroxide, and hydroxyl radicals, as byproducts of cellular respiration [Researchers have discovered that increasing the levels of antioxidants (including glutathione, The efficacy of vitamin C, a potent free radical scavenger, in exercise-induced oxidative stress has been studied; however, the results remain controversial. Several studies have shown that vitamin C supplementation is beneficial in regulating redox balance and reducing the production of oxidative stress biomarkers during exercise, such as lipid peroxidation and protein carbonyl [Glutathione is a powerful antioxidant found in all cells of the human body [The biochemical processes of vitamin C and GSH are closely connected [This study aimed to investigate the acute effects of natural antioxidants derived from yeast fermentation containing glutathione and dietary vitamin C on metabolic function, skeletal muscle oxygenation, cardiac function, and antioxidant function during prolonged submaximal exercise. We hypothesized that acute dietary vitamin C and glutathione supplementation may result in greater improvements in metabolic function, skeletal muscle oxygenation, cardiac function, and antioxidant function during prolonged submaximal exercise in middle-aged triathlon athletes.