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NCT Number: NCT07118904

Effect of Dehydration on Sleep Quality, Cognitive Skills, and Electromyographic Responses in Combat Athletes

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.

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Key information

Age range

17 year–28 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

Bolu Abant İzzet Baysal University, Faculty of Sport Sciences,

Bolu, 14030, Turkey (Türkiye)

Location status: Recruiting

Location contact

Koray Gökmen, Ms

SUB_INVESTIGATOR

Semih Karaman, Ms

SUB_INVESTIGATOR

Umid Karli, PhD

CONTACT

[email protected]

Umid Karlı, Phd

PRINCIPAL_INVESTIGATOR

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Voluntary participation
  • Being combat athletes with prior rapid weight loss experience
  • No existing health conditions
  • No orthopedic injuries

Exclusion criteria

  • Using of sleep-related medications
  • Complications During the Intervention: Participants who experience any complications during experimental intervention.

Treatment and study plan

Rapid weight loss through dehydration

Other

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.

Primary outcomes

  1. Sleep monitoring and Evaluation

    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).

    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.

  2. Isokinetic Leg Strength Measurement

    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).

    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.

  3. EMG Measurements

    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).

    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.

  4. Stroop test

    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).

    The Stroop test is a test that reflects frontal lobe region activity.

  5. Symbol Digit Modalities Test

    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).

    The Symbol Digit Modalities Test is a test that evaluates complex visual spatial scanning, sustained attention and concentration, information processing speed and working memory.

  6. Montreal Cognitive Assessment

    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).

    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.

Study contacts

Contact information is provided by the study sponsor or research team.

Kutlu Aydın, PhD

CONTACT

[email protected]

+90374 254 10 00 ext. 7532

Umid Karli, PhD

CONTACT

[email protected]

+90 374 254 10 00 ext. 7501

Sponsors and collaborators

Lead sponsor

Abant Izzet Baysal University

Other

Collaborators

  • The Scientific and Technological Research Council of Turkey

Registry information

Official study title

The Effect of Acute Dehydration on Sleep Quality, Cognitive Skills, and Electromyographic Responses During Maximum Contraction in Combat Athletes

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Aug 12, 2025
Registry last updated
Mar 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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