An interventional study of Rapid weight loss through dehydration in Dehydration, Weight Loss and Weight Cycling, sponsored by Abant Izzet Baysal University. Completed at 1 site in Turkey (Türkiye). Open to male participants aged 17 Years to 28 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by Abant Izzet Baysal University · Not applicable, Interventional, and Treatment
This study examines the effects of rapid dehydration-induced weight loss on combat athletes' sleep quality, cognitive skills, and isokinetic strength performance. The research documents both benefits and risks of weight-cutting practices for athletes, coaches, and medical staff in weight-class sports. Findings will guide safer weight management approaches and inform potential revisions to international weigh-in protocols, while contributing valuable insights to sports science.
The objective of this study is to examine the impact of rapid weight loss through dehydration on sleep quality, cognitive skills, and surface electromyographic (sEMG) responses during isokinetic strength performance in combat athletes. Additionally, the overall effect of acute dehydration and the potential adverse effects of dehydration on sleep quality on cognitive abilities, and sEMG responses will be evaluated. Body temperature and heart rate values will be monitored throughout the study. Finally, the effect of rehydration on cognitive skills, strength, and sEMG responses after a night of dehydration will be evaluated.
Competitive senior male combat athletes will participate in this study. The first stage will involve the determination of urine density, the recording of body weight, the measurement of body composition and total body fluid, and the recording of resting heart rate (HR) and body temperature. Subsequently, cognitive skill tests will be administered, and following a standard warm-up, sEMG data will be recorded from the dominant leg quadriceps muscle region during isokinetic leg strength measurements.
Following the completion of the pre-tests, each athlete will be subjected to two separate dehydration and control applications in accordance with the randomised crossover experimental design. In the experimental trials, 3% weight loss will be achieved with sauna application by taking the body weights recorded in the pre-test as a reference. Following the dehydration application, all measurements taken in the pre-test before the application will be repeated in order after approximately 45 minutes, with the athlete refraining from consuming any food or liquid.
Athletes in experimental trial 1 will be permitted to engage in a routine night without rehydration. During this period, their sleep quality will be recorded with a sleep monitor. The next day in the morning, all measurements taken in the pre-test will be repeated in order to evaluate the effect of dehydration and the possible negative effect of dehydration on sleep quality on the dependent variables. Following the completion of the morning measurements, the athletes will be permitted to consume fluids and food within two hours in order to reach their body weights in the pre-test. All tests will be reapplied for the last time to the athletes who have reached the state of rehydration, respectively. In the experimental trial 2, they will be permitted to rehydrate after the second measurements and will be asked to spend a routine night. The remaining tests will be repeated in accordance with the experimental trial 1 protocol. In the control trial, all tests in the experimental trials will be performed without body weight loss due to dehydration. All participants will be randomly assigned to the dehydration and control trials, with each athlete participating in the respective trial at one-week intervals.
201 studies on the registry are indexed under Dehydration; 28 are open to participants now.
This study's enrollment of 12 is below the median of 43 across 145 interventional studies indexed under Dehydration.
Browse Dehydration studies →Abant Izzet Baysal University is the lead sponsor of 250 studies on the registry; 59 are open to participants now.
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Exclusion Criteria:
In this trial 3% weight loss will be achieved with sauna application by taking the body weights recorded in the pre-test as a reference. Following the dehydration application, all measurements taken in the pre-test before the application will be repeated in order after approximately 45 minutes. Athletes will be permitted to engage in a routine night without rehydration. During this period, their sleep quality will be recorded with a sleep tracker. The next day in the morning, all measurements taken in the pre-test will be repeated in order to evaluate the effect of dehydration and the possible negative effect of dehydration on sleep quality on the dependent variables. Following the completion of the morning measurements, the athletes will be permitted to consume fluids and food within two hours in order to reach their body weights in the pre-test. All tests will be reapplied for the last time to the athletes who have reached the state of rehydration, respectively.
Other: Rapid weight loss through dehydration
In this trial 3% weight loss will be achieved with sauna application by taking the body weights recorded in the pre-test as a reference. Following the dehydration application, all measurements taken in the pre-test before the application will be repeated in order after approximately 45 minutes, with the athlete refraining from consuming any food or liquid. Athletes will be permitted to rehydrate after the second measurements and will be asked to spend a routine night. The remaining tests will be repeated in accordance with the experimental trial 1 protocol.
Other: Rapid weight loss through dehydration
No intervention will be conducted. All tests to be used to measure dependent variables will be conducted in accordance with the Experimental trial 1 protocol.
Dehydration will be induced by exposing athletes to sauna heat with an average temperature of 70-80°C. The participants will undergo consecutive 15 minute sessions in sauna with 5 minute breaks until 3% weight loss is achieved. No liquids or food will be consumed between sessions.
Sleep monitoring and Evaluation
Participants' sleep assessments will be conducted with a sleep monitor, which uses impulse radio ultra-wide band (IR-UWB) radar and Doppler technology, and has been shown to provide measurements as accurate and reliable as the polysomnography device, which is considered the gold standard in sleep assessment. Total sleep and wake times and durations of the sleep phases will be obtained in minutes from the recordings of the device.
Time frame: First trial monitoring, following one week Second trial monitoring and following one week Third trial monitoring (Due to randomized counterbalanced crossover design, monitoring will be performed three times, two as experimental and one as control).
Isokinetic Leg Strength Measurement
Isokinetic leg strength measurements will be made with the Cybex Norm device. Peak torque data obtained during the measurements will be recorded and used in data processing.
Time frame: First trial testing, following one week Second trial testing and following one week Third trial testing (Due to randomized counterbalanced crossover design, testing will be performed three times, two as experimental and one as control).
EMG Measurements
Electrical potentials of muscle cells are recorded with electromyography (EMG) and the activities of skeletal muscles are evaluated based on changes in these potentials. EMG measurement provides information about the muscles and motor nerves involved by analyzing motor unit action potentials.
Time frame: First trial testing, following one week Second trial testing and following one week Third trial testing (Due to randomized counterbalanced crossover design, testing will be performed three times, two as experimental and one as control).
Stroop test
The Stroop test is a test that reflects frontal lobe region activity.
Time frame: First trial testing, following one week Second trial testing and following one week Third trial testing (Due to randomized counterbalanced crossover design, testing will be performed three times, two as experimental and one as control).
Symbol Digit Modalities Test
The Symbol Digit Modalities Test is a test that evaluates complex visual spatial scanning, sustained attention and concentration, information processing speed and working memory.
Time frame: First trial testing, following one week Second trial testing and following one week Third trial testing (Due to randomized counterbalanced crossover design, testing will be performed three times, two as experimental and one as control).
Montreal Cognitive Assessment
The Montreal Cognitive Assessment test evaluates cognitive functions such as attention and concentration, executive functions, memory, language, visual construction skills, calculation and orientation. The test scores range from 0 to 30, with a cut-off score of 21. Scores of 21 and above are considered normal.
Time frame: First trial testing, following one week Second trial testing and following one week Third trial testing (Due to randomized counterbalanced crossover design, testing will be performed three times, two as experimental and one as control).
Ran from Aug 2025 to primary completion in Jun 2026, 10 months.
Of 65 non-industry interventional studies with no phase under Dehydration, half reached primary completion within 8 months of starting (the median), counting those still running; a quarter within 5 and three quarters within 18. This study's 10 months is above that.
Counting every sponsor, half of 73 studies reached it within 9 months; a quarter within 5 and three quarters within 18.
Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 16, 2026: primary completion May 2026 → Jun 2026 and completion Aug 2026 → Sep 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is completed, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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