2.2. Study Design
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The design of this study, which was a double-blind, cross-over, placebo-controlled trial, is illustrated in At the first visit, the participants arrived after an 8-hour fast to undergo body composition measurements. After stabilization, they performed a graded exercise test (GXT) using a cycle ergometer (Aerobike 75XLIII, Konami Corporation, Tokyo, Japan) to evaluate VODuring the remaining four visits, participants performed each exercise trial with four different supplements: placebo (Pla), vitamin C (VitC), glutathione (Glu), and combined vitamin C and glutathione (VitC+Glu) supplements. For the exercise trials, the participants arrived at the laboratory after fasting for 4 h. Upon arrival, the participants consumed a 100 mL solution containing either supplements or placebo and then rested for 1 h. They performed a 90 min bout of prolonged submaximal exercise using a cycle ergometer (Aerobike 75XLIII, Konami Corporation, Tokyo, Japan) at a predetermined intensity (workload of 70% VOAll exercise trial sessions were performed in a 9 m × 7 m × 3 m (width × length × height) environmental control chamber (NCTC-1, Nara Control, Seoul, Republic of Korea) at a temperature of 23 ± 1 °C and humidity of 50 ± 5% regulated by an environmental control chamber.