Load and Hold: Impact of 7-Day Creatine Monohydrate Loading on Breath-Hold Cycling Performance

The present study aims to investigate the effects of creatine monohydrate supplementation on maximal breath-hold exercise performance on a bicycle ergometer in trained breath-hold divers. The testing protocol is specifically designed to replicate the physiological demands and exercise intensity of a maximal dynamic breath-hold dive. Creatine supplementation may improve breath-hold exercise capacity by acting as a rapid, anaerobic energy source that is independent of oxygen availability that does not generate fatigue-inducing metabolic byproducts. Furthermore, its intracellular buffering properties may help delay the onset of metabolic acidosis, thereby possibly prolonging muscular work under hypoxic conditions. Therefore, the main questions the study aims to answer are: 1. Can creatine monohydrate loading supplementation protocol improve breath-hold exercise performance by increasing total work (TW) and time to exhaustion (TTE)? 2. Can it will increase lactate threshold and delay the onset of the metabolic acidosis? Researchers will compare creatine monohydrate supplementation to a placebo (maltodextrin) to determine whether creatine improves maximal breath-hold exercise performance on a bicycle ergometer in trained breath-hold divers. Participants will: 1. Attend scheduled laboratory visits on 4 occasions (one for performing graded exercise test (GXT), one for familiarization with the breath-hold exercise (BHE) protocol, one for pre-supplementation BHE testing, one for post-supplementation BHE testing) 2. Take creatine monohydrate or a placebo for 7 days (5g four times per day) 3. Report any discomforts during supplementation period, log the type and frequency of their trainings 7 days prior to pre and post-supplementation testing, report everything they ate and drunk on the day prior to the pre and post-supplementation testing

NCT Number	NCT07233707
Lead Sponsor	Harokopio University Collaborators: National and Kapodistrian University of Athens, University of Belgrade
Conditions	Healthy
Enrollment	26 participants
Start Date	2025-07-24
Primary Completion	2025-11-26 (estimated)
Study Completion	2026-08-26 (estimated)
Updated on ClinicalTrials.gov	2025-11-18