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

NCT07233707 | Enrolling By Invitation

• 1 other identifier: 3301/21-07-2025
• Study Type: interventional
• Target: 26
• Locations: 1 country
• Sites: 1

Brief Summary

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. 1.Can creatine monohydrate loading supplementation protocol improve breath-hold exercise performance by increasing total work (TW) and time to exhaustion (TTE)?
2. 2.Can it will increase lactate threshold and delay the onset of the metabolic acidosis?
3. 3.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)
4. 4.Take creatine monohydrate or a placebo for 7 days (5g four times per day)
5. 5.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

Conditions

Healthy

Keywords

breath-hold exercise performance; creatine monohydrate loading; supplementation; bicycle ergometer; ergogenic aid; anaerobic endurance performance; nutritional intervention

Outcome Measures

Primary Outcomes (3)

• Total Work

  Performance will be evaluated based on two parameters, one of which is Total Work (TW). TW will represent distance covered on the bicycle ergometer on the maximum breath-hold exercise attempt. It will be measured on the bicycle ergometer Monark 839 E and expressed in meters.

  From enrollment to study (baseline/pre-supplementation testing) to end of the study (post-supplementation testing which takes place after 7 days of supplementation period)

• Time to Exhaustion

  Performance will be evaluated based on two parameters, one of which is Time to Exhaustion (TTE). TTE will represent duration of the breath-hold during the maximum breath-hold exercise attempt. It will be measured on the bicycle ergometer Monark 839 E and expressed in seconds.

  From enrollment to study (baseline/pre-supplementation testing) to end of the study (post-supplementation testing which takes place after 7 days of supplementation period)

• Lactate accumulation

  Lactate accumulation (the difference between lactate concentration in peripheral circulation immediately after exercise and that measured three minutes before exercise) will represent an objective indicator of fatigue. It will be measured from the earlobe using Lactate Scout 4 device, before and after maximum breath-hold exercise attempt, on both pre and post supplementation testing.

  From enrollment to study (baseline/pre-supplementation testing) to end of the study (post-supplementation testing which takes place after 7 days of supplementation period)

Secondary Outcomes (2)

• Rating of Perceived Exertion

  From enrollment to study (baseline/pre-supplementation testing) to end of the study (post-supplementation testing which takes place after 7 days of supplementation period)

• Change in Lean Body Mass

  From enrollment to study (baseline/pre-supplementation testing) to end of the study (post-supplementation testing which takes place after 7 days of supplementation period)

Study Arms (2)

Creatine monohydrate (CM) group

EXPERIMENTAL

CM group will receive 20 grams of creatine monohydrate per day for 7 days

Dietary Supplement: Creatine Monohydrate

Placebo (PL) group

PLACEBO COMPARATOR

PL group will receive 20 grams of maltodextrin per day for 7 days

Dietary Supplement: Placebo Control

Interventions

Creatine Monohydrate DIETARY_SUPPLEMENT

Creatine monohydrate 7-day loading phase

Creatine monohydrate (CM) group

Placebo Control DIETARY_SUPPLEMENT

20 grams of maltodextrin per day for 7 days

Placebo (PL) group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• healthy trained breath-hold divers (with at least one year of experience in dynamic breath-hold diving training and competition) who haven't been supplementing with creatine monohydrate for at least the past 6 weeks prior to the start of the study

You may not qualify if:

• breath-hold divers with less than 1 year of experience in dynamic breath-hold training and competition
• breath-hold divers with any acute or chronic medical conditions
• breath-hold divers that supplement with creatine monohydrate or have been supplementing with creatine monohydrate in the past 6 weeks

Sponsors & Collaborators

• Harokopio University: lead
• National and Kapodistrian University of Athens: collaborator
• University of Belgrade: collaborator

Study Sites (1)

Harokopio University

Athens, Kallithea, Greece

Location

Related Publications (10)

• Nelson AG, Day R, Glickman-Weiss EL, Hegsted M, Kokkonen J, Sampson B. Creatine supplementation alters the response to a graded cycle ergometer test. Eur J Appl Physiol. 2000 Sep;83(1):89-94. doi: 10.1007/s004210000244.

  PMID: 11072779 BACKGROUND

• McNaughton LR, Dalton B, Tarr J. The effects of creatine supplementation on high-intensity exercise performance in elite performers. Eur J Appl Physiol Occup Physiol. 1998 Aug;78(3):236-40. doi: 10.1007/s004210050413.

  PMID: 9721002 BACKGROUND

• Furtado ETF, Oliveira JPL, Pereira ISB, Veiga EP, Silva SFD, Abreu WC. Short term creatine loading improves strength endurance even without changing maximal strength, RPE, fatigue index, blood lactate, and mode state. An Acad Bras Cienc. 2024 May 10;96(2):e20230559. doi: 10.1590/0001-3765202420230559. eCollection 2024.

  PMID: 38747788 BACKGROUND

• Lee S, Hong G, Park W, Lee J, Kim N, Park H, Park J. The effect of short-term creatine intake on blood lactic acid and muscle fatigue measured by accelerometer-based tremor response to acute resistance exercise. Phys Act Nutr. 2020 Mar 31;24(1):29-36. doi: 10.20463/pan.2020.0006.

  PMID: 32408412 BACKGROUND

• Oliver JM, Joubert DP, Martin SE, Crouse SF. Oral creatine supplementation's decrease of blood lactate during exhaustive, incremental cycling. Int J Sport Nutr Exerc Metab. 2013 Jun;23(3):252-8. doi: 10.1123/ijsnem.23.3.252. Epub 2012 Nov 19.

  PMID: 23164647 BACKGROUND

• Goodwin ML, Harris JE, Hernandez A, Gladden LB. Blood lactate measurements and analysis during exercise: a guide for clinicians. J Diabetes Sci Technol. 2007 Jul;1(4):558-69. doi: 10.1177/193229680700100414.

  PMID: 19885119 BACKGROUND

• Hirvonen J, Nummela A, Rusko H, Rehunen S, Harkonen M. Fatigue and changes of ATP, creatine phosphate, and lactate during the 400-m sprint. Can J Sport Sci. 1992 Jun;17(2):141-4.

  PMID: 1324108 BACKGROUND

• RodrIguez-Zamora L, Engan HK, Lodin-Sundstrom A, Schagatay F, Iglesias X, Rodriguez FA, Schagatay E. Blood lactate accumulation during competitive freediving and synchronized swimming. Undersea Hyperb Med. 2018 Jan-Feb;45(1):55-63.

  PMID: 29571233 BACKGROUND

• Cooper R, Naclerio F, Allgrove J, Jimenez A. Creatine supplementation with specific view to exercise/sports performance: an update. J Int Soc Sports Nutr. 2012 Jul 20;9(1):33. doi: 10.1186/1550-2783-9-33.

  PMID: 22817979 BACKGROUND

• Forbes SC, Candow DG, Neto JHF, Kennedy MD, Forbes JL, Machado M, Bustillo E, Gomez-Lopez J, Zapata A, Antonio J. Creatine supplementation and endurance performance: surges and sprints to win the race. J Int Soc Sports Nutr. 2023 Dec;20(1):2204071. doi: 10.1080/15502783.2023.2204071.

  PMID: 37096381 BACKGROUND

MeSH Terms

Interventions

Creatine

Intervention Hierarchy (Ancestors)

Guanidines; Amidines; Organic Chemicals; Amino Acids; Amino Acids, Peptides, and Proteins

Study Officials

• Natalija Kurmazovic, Master of Science

  Faculty of Pharmacy, University of Belgrade

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: September 9, 2025
• First Posted: November 18, 2025
• Study Start: July 24, 2025
• Primary Completion: November 26, 2025
• Study Completion (Estimated): August 26, 2026
• Last Updated: November 18, 2025

Record last verified: 2025-11

Locations

GR (1)