An interventional study of Continuous Positive Airway Pressure (CPAP) and Physical Training in Healthy Athlete, sponsored by Federal University of São Paulo. Completed at 1 site in Brazil. Open to male participants aged 20 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by Federal University of São Paulo · Not applicable, Interventional, and Other
This study evaluated the use of nocturnal continuous positive airway pressure (CPAP) as a potential recovery strategy in healthy male endurance runners without obstructive sleep apnea. Participants completed periods of high-intensity/high-volume and low-intensity/low-volume physical training, first without CPAP and subsequently with nocturnal CPAP. Sleep, physiological, biochemical, psychological, and recovery-related measures were assessed during the study. Polysomnography, blood tests, questionnaires, actigraphy, sleep diaries, and heart rate monitoring were used to evaluate participants across the experimental periods. The objective was to investigate whether nocturnal CPAP was associated with changes in recovery-related measures during different physical training loads.
The objective of this interventional study was to investigate the use of nocturnal continuous positive airway pressure (CPAP) in the recovery of high-performance endurance runners during different physical training loads.
Male endurance runners aged 20 to 45 years were screened for participation. Initial assessments included polysomnography (PSG), otorhinolaryngological evaluation, electrocardiography (ECG), blood tests, cardiopulmonary exercise testing, and questionnaires assessing psychological and recovery-related variables.
Participants completed two sequential experimental stages. In the first stage, participants completed five days of high-intensity/high-volume training without nocturnal CPAP, followed by a two-day rest period and five days of low-intensity/low-volume training without CPAP. In the second stage, the training sequence was repeated, with participants using CPAP during sleep for the corresponding training periods. A two-day rest period separated the high- and low-intensity training periods.
At the end of each five-day training period, participants underwent polysomnography. The following morning, blood samples and questionnaire-based assessments were obtained. Actigraphy and sleep diaries were used during the study protocol, and heart rate was monitored during training.
The study used a single-group, fixed-sequence design in which participants underwent the non-CPAP conditions before the corresponding CPAP conditions.
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Participants completed a fixed-sequence training protocol consisting of high-intensity/high-volume and low-intensity/low-volume training periods. The training periods were first completed without nocturnal CPAP and subsequently repeated with nocturnal CPAP.
Device: Continuous Positive Airway Pressure (CPAP) · Behavioral: Physical Training
Participants used continuous positive airway pressure (CPAP) during sleep for five consecutive nights during each CPAP training condition.
Also known as: CPAP
Participants completed five days of high-intensity/high-volume training followed by a two-day period without training and five days of low-intensity/low-volume training. This training sequence was completed first without nocturnal CPAP and subsequently with nocturnal CPAP.
REM Sleep Latency
REM sleep latency was measured by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. REM sleep latency was measured in minutes.
Time frame: 26 days
Sleep Onset Latency
Sleep onset latency was measured by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Sleep onset latency was measured in minutes.
Time frame: 26 days
Total Sleep Time
Total sleep time was measured by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Total sleep time was measured in minutes.
Time frame: 26 days
Wake After Sleep Onset
Wake after sleep onset (WASO) was measured by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. WASO was measured in minutes.
Time frame: 26 days
Respiratory Disturbance Index
We measured the Respiratory Disturbance Index (RDI) by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions, with and without nocturnal CPAP. We expressed RDI as the number of respiratory disturbance events per hour of sleep.
Time frame: 26 days
Apnea-Hypopnea Index
Apnea-Hypopnea Index (AHI) was measured by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions, with and without nocturnal CPAP. AHI was expressed as the number of apnea and hypopnea events per hour of sleep.
Time frame: 26 days
Awakening Index
Awakening Index was measured by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions, with and without nocturnal CPAP. Awakening Index was expressed as the number of awakenings per hour of sleep.
Time frame: 26 days
Serum Aldolase
Serum aldolase was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP.
Time frame: 26 days.
Hematocrit
Hematocrit was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Hematocrit was expressed as a percentage.
Time frame: 26 days
Leukocyte Count
Leukocyte count was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Leukocyte count was expressed as ×10³/mm³.
Time frame: 26 days
Insulin-Like Growth Factor 1 (IGF-1)
Insulin-like growth factor 1 (IGF-1) was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP.
Time frame: 26 days
Serum Insulin
Serum insulin was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP.
Time frame: 26 days
Serum Uric Acid
Serum uric acid was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Uric acid was expressed in mg/dL.
Time frame: 26 days
Lactate Dehydrogenase (LDH)
Lactate dehydrogenase (LDH) was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. LDH was expressed in U/L.
Time frame: 26 days
Total Testosterone
Total testosterone was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Total testosterone was expressed in ng/dL.
Time frame: 26 days
Creatine Kinase (CK)
Creatine kinase (CK) was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. CK was expressed in U/L.
Time frame: 26 days
Sleep Efficiency
Sleep efficiency was assessed by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Sleep efficiency was expressed as the percentage of time in bed spent asleep.
Time frame: 26 days
NREM Stage 1 Sleep Percentage (S1)
The percentage of total sleep time spent in non-rapid eye movement (NREM) Stage 1 sleep was assessed by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Results were expressed as a percentage of total sleep time.
Time frame: 26 days
NREM Stage 3 Sleep Percentage (S3)
The percentage of total sleep time spent in non-rapid eye movement (NREM) Stage 3 sleep was assessed by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Results were expressed as a percentage of total sleep time.
Time frame: 26 days
REM Sleep Percentage
The percentage of total sleep time spent in rapid eye movement (REM) sleep was assessed by overnight polysomnography at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Results were expressed as a percentage of total sleep time.
Time frame: 26 days
Total Testosterone
Total testosterone was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-intensity training conditions without and with nocturnal CPAP. Total testosterone was expressed in ng/dL.
Time frame: 26 days
Free Testosterone
Free testosterone was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Free testosterone was expressed in ng/dL.
Time frame: 26 days
Serum Cortisol
Serum cortisol was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Cortisol was expressed in µg/dL.
Time frame: 26 days
Red Blood Cell Count (RBC)
Red blood cell count was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Red blood cell count was expressed as ×10⁶/mm³.
Time frame: 26 days
Hemoglobin Concentration
Hemoglobin concentration was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Hemoglobin concentration was expressed in g/dL.
Time frame: 26 days
Mean Corpuscular Volume (MCV)
Mean corpuscular volume (MCV) was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. MCV was expressed in femtoliters (fL).
Time frame: 26 days
Mean Corpuscular Hemoglobin (MCH)
Mean corpuscular hemoglobin (MCH) was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. MCH was expressed in picograms (pg).
Time frame: 26 days
Mean Corpuscular Hemoglobin Concentration (MCHC)
Mean corpuscular hemoglobin concentration (MCHC) was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. MCHC was expressed in g/dL.
Time frame: 26 days
Red Cell Distribution Width (RDW)
Red cell distribution width (RDW) was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. RDW was expressed as a percentage (%).
Time frame: 26 days
Platelet Count
Platelet count was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Platelet count was expressed as ×10³/mm³.
Time frame: 26 days
Neutrophil Count
Neutrophil count was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Neutrophil count was expressed as ×10³/mm³.
Time frame: 26 days
Eosinophil Count
Eosinophil count was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Eosinophil count was expressed as ×10³/mm³.
Time frame: 26 days
Basophil Count
Basophil count was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Basophil count was expressed as ×10³/mm³.
Time frame: 26 days
Total Lymphocyte Count
Total lymphocyte count was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Total lymphocyte count was expressed as ×10³/mm³.
Time frame: 26 days
Monocyte Count
Monocyte count was measured from blood samples obtained at baseline and after each five-day training period, including high-intensity/high-volume and low-intensity/low-volume training conditions without and with nocturnal CPAP. Monocyte count was expressed as ×10³/mm³.
Time frame: 26 days
Plan to share: No
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Ran from Jan 2012 to primary completion in Oct 2013, 21 months.
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