Abstract / Summary
Background Creatine supplementation enhances anaerobic energy availability and buffering capacity; however, its impact on muscle work under voluntary breath-hold (BH) remains unexplored. BH exercise increases reliance on anaerobic ATP production and creates a metabolic environment in which phosphocreatine-derived ATP may be particularly valuable. The aim of this study was to determine whether creatine monohydrate loading improves BH exercise performance in trained BH divers.Methods A double-blind, randomized, placebo-controlled study assessed the effects of a 7-day creatine monohydrate loading protocol (20 g/day) on performance outcomes and fatigue markers during BH exercise performed on a bicycle ergometer in 20 trained BH divers (18 males, 2 females; mean age 41.6 ± 8.6 years). The trial was registered at ClinicalTrials.gov (Identifier: NCT07233707) on 16th November 2025 under the title Load and Hold: Impact of 7-Day Creatine Monohydrate Loading on Breath-Hold Cycling Performance (BREATHE-C). Testing consisted of a brief warm-up followed by a maximal cycling trial performed on a single breath, during which participants aimed to cover the greatest possible distance. Following pre-supplementation testing, participants were randomly assigned to either the creatine monohydrate (CR) or the placebo (PL) group. Pre- and post-supplementation measurements included total work (TW), time to exhaustion (TTE), peripheral blood lactate accumulation (LA), mean partial pressure of carbon dioxide (pCO₂) in exhaled air following BH exercise, and ratings of perceived exertions for BH (RPE-BH) and muscle fatigue (RPE-MF). In addition, participants underwent dual-energy X-ray absorptiometry to assess changes in body composition.Results Significant Time × Group interactions were observed for TW (p = 0.011), TTE (p = 0.028), and fat-free mass (p = 0.017), with greater changes observed following creatine supplementation compared to PL. Furthermore, there was a significant Time × Group interaction for LA (p = 0.003), with greater changes observed in the PL group compared to CR. No significant between-group differences were observed for pCO₂, RPE-BH, RPE-MF, fat mass, or total body mass.Conclusions Creatine enhanced performance, as reflected by increases in TW and TTE, without elevating RPE-BH, although a slight increase in RPE-MF was observed. LA was lower in the CR compared to PL group, despite greater performance improvements. Overall, creatine appears to enhance BH exercise performance in trained BH divers, suggesting a potentially effective ergogenic strategy for BH-related sports.