The Effects of Beta-Alanine Supplementation on Mechanical Performance, Acid-Base Balance, Oxidative Stress, and Enzymatic Antioxidant Defence During Repeated Wingate Anaerobic Tests Under Normoxic and Hypoxic Conditions

Beta-alanine is a non-essential amino acid and the rate-limiting precursor for the synthesis of carnosine, an intracellular dipeptide found in high concentrations within skeletal muscle. Carnosine contributes to intracellular acid-base regulation by buffering hydrogen ions (H+) produced during high-intensity exercise. Supplementation with beta-alanine has consistently been shown to increase muscle carnosine concentrations, potentially enhancing buffering capacity and delaying the onset of fatigue during exercise characterized by substantial glycolytic energy production.

The ergogenic potential of beta-alanine has been extensively investigated in a variety of exercise modalities. Previous studies and meta-analyses suggest that supplementation may improve performance during high-intensity exercise lasting approximately one to four minutes, where metabolic acidosis is considered an important contributor to fatigue. However, findings remain inconsistent, particularly in exercise protocols involving repeated maximal efforts and in environmental conditions that alter oxygen availability.

Exercise performed in hypoxic environments is associated with reduced oxygen delivery to working muscles, increased reliance on anaerobic glycolysis, accelerated accumulation of hydrogen ions and lactate, and greater disturbance of acid-base homeostasis. Consequently, hypoxic exercise may increase the physiological importance of buffering mechanisms and potentially enhance the relevance of interventions aimed at improving buffering capacity. Despite this theoretical rationale, limited information is available regarding the effectiveness of beta-alanine supplementation during repeated supramaximal exercise performed under hypoxic conditions.

The purpose of this study is to evaluate the effects of four weeks of beta-alanine supplementation on repeated high-intensity cycling performance and physiological responses associated with metabolic acidosis in trained male cyclists. The study utilizes a randomized, double-blind, placebo-controlled design. Participants complete repeated laboratory testing sessions under both normoxic and normobaric hypoxic conditions before and after the supplementation period.

Exercise performance is assessed using a repeated Wingate anaerobic cycling protocol consisting of three consecutive 30-second maximal efforts separated by standardized recovery intervals. The protocol was selected because it induces substantial anaerobic energy production and metabolic stress, allowing evaluation of both performance outcomes and buffering-related physiological responses. Testing is conducted under normoxic conditions and under normobaric hypoxia corresponding to an altitude of approximately 2500 meters above sea level.