Heat ExposureNCT07593014
Effects of Creatine and Heat Exposure on Exercise Performance and Body Water Distribution
A study testing Creatine Monohydrate in people with Heat Exposure and Exercise Performance, run by University of Windsor.
Trial summary
The goal of this clinical trial is to learn whether creatine supplementation changes how the body adapts to repeated exercise in the heat in healthy recreationally active adults and varsity athletes. The study will also examine whether creatine affects fluid balance, blood volume changes and exercise performance. Read more about this study
- Who is it for?
- Ages 18 to 27 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Heat Exposure, Exercise Performance, Hydration
- What is being tested?
- Creatine Monohydrate
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 25 participants
- Where
- No sites listed yet
- Study dates
- 30 Jul 2026to 30 Aug 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 27 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy biological males between 18 and 27 years of age
- Recreationally active males and varsity athletes
- Able to safely participate in moderate-intensity exercise and heat exposure
- Willing to maintain habitual diet and physical activity throughout the study
- Willing to refrain from additional dietary supplementation during study participation
- Able to attend all required laboratory visits and heat exposure sessions
- Able to provide informed consent
Who cannot join
- History of cardiovascular, metabolic, respiratory, renal, neurological, or heat-related illness
- Contraindications to exercise testing or heat exposure identified during health screening
- Current musculoskeletal injury limiting exercise participation
- Current use of creatine supplementation or inability to complete the required washout period
- Current use of medications or supplements known to affect hydration, thermoregulation, cardiovascular function, or exercise performance
- Known allergy or intolerance to creatine monohydrate, maltodextrin, or orange juice
Show all 9Show fewer
- Inability to comply with study procedures or supplementation protocol
- Resting tympanic temperature ≥38.0°C prior to a heat exposure session
- Participation in another research study that may interfere with this protocol
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Creatine Monohydrate Supplementation During Repeated Heat Exposure: Effects on Fluid Balance and Exercise Performance in a Randomized Double-Blind, Placebo-Controlled Trial
The goal of this clinical trial is to learn whether creatine supplementation changes how the body adapts to repeated exercise in the heat in healthy recreationally active adults and varsity athletes. The study will also examine whether creatine affects fluid balance, blood volume changes and exercise performance.
The main questions it aims to answer are:
Read more
Does creatine supplementation increase plasma volume and total body water during repeated heat exposure more than placebo? Does creatine supplementation improve exercise performance after heat acclimation more than placebo? Does creatine supplementation influence cardiovascular responses to heat stress?
Researchers will compare a creatine supplementation group to a placebo group to determine whether creatine changes the magnitude of heat acclimation adaptations.
Participants will:
Complete baseline measurements of body composition, hydration, blood markers, and exercise performance.
Consume either creatine monohydrate or a placebo supplement daily Complete repeated supervised exercise sessions in a controlled heated environment Undergo repeated assessments of body water, temperature, heart rate, and exercise performance throughout the study
Read the detailed description
Heat acclimation (HA) is a physiological adaptation process that occurs following repeated exposure to hot environmental conditions. HA is associated with several beneficial cardiovascular and thermoregulatory adaptations, including plasma volume expansion, improved heat tolerance, lower physiological strain during exercise, and improved exercise performance in hot and temperate environments. However, substantial variability exists in the magnitude and rate of adaptation between individuals.
Creatine monohydrate supplementation is widely used to improve high-intensity exercise performance and is known to increase intracellular water retention within skeletal muscle. Because HA also influences fluid regulation and plasma volume expansion, creatine supplementation may alter fluid distribution and cardiovascular responses during repeated heat exposure. Despite this theoretical interaction, limited research has investigated the combined effects of creatine supplementation and HA on fluid balance and exercise performance.
The purpose of this randomized, double-blind, placebo-controlled trial is to examine whether creatine monohydrate supplementation influences body-fluid distribution, plasma volume expansion, and exercise performance during repeated heat exposure in healthy recreationally active males and varsity athletes.
Participants will complete baseline testing consisting of body composition assessment, body water measurement, capillary blood sampling, resting temperature assessment, and cardiorespiratory and musculoskeletal performance testing using cycle ergometry. Participants will then be randomly assigned to receive either creatine monohydrate or a placebo supplement under double-blind conditions.
The supplementation protocol will include a 7-day loading phase followed by a maintenance phase throughout the remainder of the study. Following supplementation, participants will complete 7 consecutive days of supervised heat exposure consisting of moderate-intensity cycling in a heated environment designed to elevate body temperature and induce heat acclimation adaptations.
Throughout the study, researchers will assess changes in plasma volume, total body water, resting temperature, heart rate responses, and exercise performance. Physiological monitoring will occur during all heat exposure sessions to support participant safety.
The findings from this study may improve understanding of how creatine supplementation influences fluid regulation and adaptation to heat stress. Results may have implications for athletes, physically active individuals, and occupational populations exposed to hot environmental conditions.
- Conditions
- Heat Exposure, Exercise Performance, Hydration, Body Fluid Compartments, Creatine Supplementation, Placebo - Control
- Being tested
- Creatine Monohydrate, Maltodextrin (Placebo)
- Keywords
- Creatine Monohydrate, Heat Exposure, Heat Acclimation, Short Term Heat Acclimation, Plasma Volume, Fluid Balance, Body Fluid Compartments, Wingate Test, VO2 Max, Cardiorespiratory Performance, Musculoskeletal Performance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Creatine MonohydrateDietary supplement
Participants assigned to this intervention will consume micronized creatine monohydrate during a 7-day loading phase at 0.3 g·kg-¹·day-¹ followed by a maintenance dose of 0.03 g·kg-¹·day-¹ during the heat acclimation protocol. Supplements will be dissolved in orange juice and consumed under supervision during laboratory visits. Creatine supplementation will continue throughout the heat acclimation period.
Maltodextrin (Placebo)Dietary supplement
Participants will consume maltodextrin matched to creatine supplementation appearance and dosing schedule during the loading and maintenance phases of the study.
| Study group | Role | What they receive |
|---|---|---|
| Creatine Monohydrate + Heat Exposure | Experimental | Participants assigned to this arm will complete a 7-day creatine monohydrate loading phase followed by daily maintenance supplementation during a 7-day heat acclimation protocol. Participants will complete daily supervised heat exposure sessions consisting of cycling exercise in a controlled hot environment. Receives: Dietary Supplement: Creatine Monohydrate |
| Placebo + Heat Exposure | Placebo comparator | Participants assigned to this arm will consume a placebo supplement (maltodextrin) matched in appearance and dosing schedule to the creatine condition during a 7-day heat acclimation protocol. Participants will complete daily supervised heat exposure sessions consisting of cycling exercise in a controlled hot environment. Receives: Dietary Supplement: Maltodextrin (Placebo) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Plasma Volume Change Following Heat Acclimation and Creatine Supplementation
Percent change in plasma volume estimated from capillary blood hematocrit measurements. Following centrifugation, packed red blood cell volume and plasma layers will be measured using a microhematocrit reader, and hematocrit will be expressed as a percentage of total blood volume. Relative changes in blood volume and plasma volume will be inferred from repeated hematological measurements obtained at standardized time points throughout the study.
Measured: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Secondary outcomes (5)
Change in Total Body Water
Total body water measured using bioelectrical impedance analysis (InBody 230).
Measured: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Change in Intracellular Water
Intracellular water estimated using bioelectrical impedance analysis.
Measured: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Change in Extracellular Water
Extracellular water estimated using bioelectrical impedance analysis.
Measured: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Change in VO₂ Peak
VO₂ peak assessed during supramaximal cycling exercise using breath-by-breath metabolic gas analysis.
Measured: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Change in Musculoskeletal Performance
Musculoskeletal performance assessed during supramaximal cycling exercise using peak and mean power output measures.
Measured: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 May 2026
- Study start30 Jul 2026 (estimated)
- Primary completion30 Apr 2027 (estimated)
- Study completion30 Aug 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (6)Papers the sponsor has linked to this study.
- Other trials for Heat ExposureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 25 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Windsor
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Dr. Andrew S. Perrotta, University of Windsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07593014
- Sponsor's protocol ID
- #26-057
- Status last verified
- May 2026
- First submitted
- 11 May 2026
- Last updated
- 18 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Wenger CB (2003). Human adaptation to hot environments. In K. B. Pandolf, M. N. Sawka, & R. R. Gonzalez (Eds.), Human performance physiology and environmental medicine at terrestrial extremes (pp. 379-438). Benchmark Press.
Mack, G.W. and Nadel, E.R. (1994), Body Fluid Balance During Heat Stress in Humans. Comprehensive Physiology, 1994: 187-214. https://doi.org/10.1002/j.2040-4603.1994.tb01156.x
Periard JD, Racinais S, Sawka MN. Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports. Scand J Med Sci Sports. 2015 Jun;25 Suppl 1:20-38. doi: 10.1111/sms.12408.
PubMed 25943654Lorenzo S, Halliwill JR, Sawka MN, Minson CT. Heat acclimation improves exercise performance. J Appl Physiol (1985). 2010 Oct;109(4):1140-7. doi: 10.1152/japplphysiol.00495.2010. Epub 2010 Aug 19.
PubMed 20724560Kreider RB, Kalman DS, Antonio J, Ziegenfuss TN, Wildman R, Collins R, Candow DG, Kleiner SM, Almada AL, Lopez HL. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017 Jun 13;14:18. doi: 10.1186/s12970-017-0173-z. eCollection 2017.
PubMed 28615996Dill DB, Costill DL. Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. J Appl Physiol. 1974 Aug;37(2):247-8. doi: 10.1152/jappl.1974.37.2.247. No abstract available.
PubMed 4850854
Study at a glance
From the registry record, last updated by the sponsor on 18 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Creatine Monohydrate Supplementation During Repeated Heat Exposure: Effects on Fluid Balance and Exercise Performance in a Randomized Double-Blind, Placebo-Controlled Trial
- ClinicalTrials.gov ID
- NCT07593014
- Acronym / sponsor ID
- #26-057
- Conditions
- Heat Exposure, Exercise Performance, Hydration, Body Fluid Compartments, Creatine Supplementation, Placebo - Control
- Keywords
- Creatine Monohydrate, Heat Exposure, Heat Acclimation, Short Term Heat Acclimation, Plasma Volume, Fluid Balance, Body Fluid Compartments, Wingate Test
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 25 participants (estimated)
- Lead sponsor
- University of WindsorUniversity, hospital or other
- Study start
- 30 Jul 2026 (estimated)
- Primary completion
- 30 Apr 2027 (estimated)
- Study completion
- 30 Aug 2027 (estimated)
- First posted
- 18 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to learn whether creatine supplementation changes how the body adapts to repeated exercise in the heat in healthy recreationally active adults and varsity athletes. The study will also examine whether creatine affects fluid balance, blood volume changes and exercise performance.
The main questions it aims to answer are:
Does creatine supplementation increase plasma volume and total body water during repeated heat exposure more than placebo? Does creatine supplementation improve exercise performance after heat acclimation more than placebo? Does creatine supplementation influence cardiovascular responses to heat stress?
Researchers will compare a creatine supplementation group to a placebo group to determine whether creatine changes the magnitude of heat acclimation adaptations.
Participants will:
Complete baseline measurements of body composition, hydration, blood markers, and exercise performance.
Consume either creatine monohydrate or a placebo supplement daily Complete repeated supervised exercise sessions in a controlled heated environment Undergo repeated assessments of body water, temperature, heart rate, and exercise performance throughout the study
Detailed description
Heat acclimation (HA) is a physiological adaptation process that occurs following repeated exposure to hot environmental conditions. HA is associated with several beneficial cardiovascular and thermoregulatory adaptations, including plasma volume expansion, improved heat tolerance, lower physiological strain during exercise, and improved exercise performance in hot and temperate environments. However, substantial variability exists in the magnitude and rate of adaptation between individuals.
Creatine monohydrate supplementation is widely used to improve high-intensity exercise performance and is known to increase intracellular water retention within skeletal muscle. Because HA also influences fluid regulation and plasma volume expansion, creatine supplementation may alter fluid distribution and cardiovascular responses during repeated heat exposure. Despite this theoretical interaction, limited research has investigated the combined effects of creatine supplementation and HA on fluid balance and exercise performance.
The purpose of this randomized, double-blind, placebo-controlled trial is to examine whether creatine monohydrate supplementation influences body-fluid distribution, plasma volume expansion, and exercise performance during repeated heat exposure in healthy recreationally active males and varsity athletes.
Participants will complete baseline testing consisting of body composition assessment, body water measurement, capillary blood sampling, resting temperature assessment, and cardiorespiratory and musculoskeletal performance testing using cycle ergometry. Participants will then be randomly assigned to receive either creatine monohydrate or a placebo supplement under double-blind conditions.
The supplementation protocol will include a 7-day loading phase followed by a maintenance phase throughout the remainder of the study. Following supplementation, participants will complete 7 consecutive days of supervised heat exposure consisting of moderate-intensity cycling in a heated environment designed to elevate body temperature and induce heat acclimation adaptations.
Throughout the study, researchers will assess changes in plasma volume, total body water, resting temperature, heart rate responses, and exercise performance. Physiological monitoring will occur during all heat exposure sessions to support participant safety.
The findings from this study may improve understanding of how creatine supplementation influences fluid regulation and adaptation to heat stress. Results may have implications for athletes, physically active individuals, and occupational populations exposed to hot environmental conditions.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Creatine Monohydrate + Heat Exposure | Experimental | Dietary Supplement: Creatine MonohydrateParticipants assigned to this arm will complete a 7-day creatine monohydrate loading phase followed by daily maintenance supplementation during a 7-day heat acclimation protocol. Participants will complete daily supervised heat exposure sessions consisting of cycling exercise in a controlled hot environment. |
| Placebo + Heat Exposure | Placebo comparator | Dietary Supplement: Maltodextrin (Placebo)Participants assigned to this arm will consume a placebo supplement (maltodextrin) matched in appearance and dosing schedule to the creatine condition during a 7-day heat acclimation protocol. Participants will complete daily supervised heat exposure sessions consisting of cycling exercise in a controlled hot environment. |
Who may qualify
- Ages
- 18 to 27 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Healthy biological males between 18 and 27 years of age
- Recreationally active males and varsity athletes
- Able to safely participate in moderate-intensity exercise and heat exposure
- Willing to maintain habitual diet and physical activity throughout the study
- Willing to refrain from additional dietary supplementation during study participation
Key exclusion criteria (9 listed)
- History of cardiovascular, metabolic, respiratory, renal, neurological, or heat-related illness
- Contraindications to exercise testing or heat exposure identified during health screening
- Current musculoskeletal injury limiting exercise participation
- Current use of creatine supplementation or inability to complete the required washout period
- Current use of medications or supplements known to affect hydration, thermoregulation, cardiovascular function, or exercise performance
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Creatine MonohydrateParticipants assigned to this intervention will consume micronized creatine monohydrate during a 7-day loading phase at 0.3 g·kg-¹·day-¹ followed by a maintenance dose of 0.03 g·kg-¹·day-¹ during the heat acclimation protocol. Supplements will be dissolved in orange juice and consumed under supervision during laboratory visits. Creatine supplementation will continue throughout the heat acclimation period. | Dietary supplement | Creatine Monohydrate + Heat Exposure |
| Maltodextrin (Placebo)Participants will consume maltodextrin matched to creatine supplementation appearance and dosing schedule during the loading and maintenance phases of the study. | Dietary supplement | Placebo + Heat Exposure |
Primary outcome
Plasma Volume Change Following Heat Acclimation and Creatine Supplementation
Time frame: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Percent change in plasma volume estimated from capillary blood hematocrit measurements. Following centrifugation, packed red blood cell volume and plasma layers will be measured using a microhematocrit reader, and hematocrit will be expressed as a percentage of total blood volume. Relative changes in blood volume and plasma volume will be inferred from repeated hematological measurements obtained at standardized time points throughout the study.
5 secondary outcomes
Change in Total Body Water
Time frame: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Change in Intracellular Water
Time frame: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Change in Extracellular Water
Time frame: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Change in VO₂ Peak
Time frame: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Change in Musculoskeletal Performance
Time frame: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 May 2026.
- BackgroundWenger CB (2003). Human adaptation to hot environments. In K. B. Pandolf, M. N. Sawka, & R. R. Gonzalez (Eds.), Human performance physiology and environmental medicine at terrestrial extremes (pp. 379-438). Benchmark Press.
- BackgroundMack, G.W. and Nadel, E.R. (1994), Body Fluid Balance During Heat Stress in Humans. Comprehensive Physiology, 1994: 187-214. https://doi.org/10.1002/j.2040-4603.1994.tb01156.x
- Background: PubMed 25943654Periard JD, Racinais S, Sawka MN. Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports. Scand J Med Sci Sports. 2015 Jun;25 Suppl 1:20-38. doi: 10.1111/sms.12408.
- Background: PubMed 20724560Lorenzo S, Halliwill JR, Sawka MN, Minson CT. Heat acclimation improves exercise performance. J Appl Physiol (1985). 2010 Oct;109(4):1140-7. doi: 10.1152/japplphysiol.00495.2010. Epub 2010 Aug 19.
- Background: PubMed 28615996Kreider RB, Kalman DS, Antonio J, Ziegenfuss TN, Wildman R, Collins R, Candow DG, Kleiner SM, Almada AL, Lopez HL. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017 Jun 13;14:18. doi: 10.1186/s12970-017-0173-z. eCollection 2017.
- Background: PubMed 4850854Dill DB, Costill DL. Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. J Appl Physiol. 1974 Aug;37(2):247-8. doi: 10.1152/jappl.1974.37.2.247. No abstract available.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
A study testing Creatine Monohydrate in people with Heat Exposure and Exercise Performance, run by University of Windsor.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 18 May 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Andrew S Perrotta, Phd (604 679 7172, Andrew.Perrotta@uwindsor.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Plasma Volume Change Following Heat Acclimation and Creatine Supplementation (time frame: Measured at baseline (pre-supplementation), after 7 days of creatine/placebo loading, and after 7 days of heat acclimation.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07593014, which also lists 6 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 May 2026.