Exercise Interventions in Obstructive Sleep Apnea Syndrome

The Effect of Exercise Snacks and Aerobic Exercise on Circadian Rhythm and Functional Capacity in Individuals With Obstructive Sleep Apnea Syndrome

Obstructive Sleep Apnea Syndrome (OSA) is a condition characterized by repeated pauses or reductions in breathing during sleep, which can negatively affect sleep quality, daytime functioning, and physical capacity. Although regular exercise is known to have beneficial effects in OSA, the effects of different exercise approaches on circadian rhythm and functional capacity have not been sufficiently investigated.The primary aim of this study is to compare the effects of exercise snacking and aerobic exercise on circadian rhythm and functional capacity in individuals with OSA, in comparison with a control group. The secondary aim is to evaluate the effects of these exercise interventions on peripheral muscle strength, fatigue level, body composition, quality of life, and physical activity level.Participants will be randomly assigned to three groups: an aerobic exercise group, an exercise snacking group, and a control group. While the exercise groups will follow their respective intervention programs, the control group will continue their routine treatment.This study aims to answer whether exercise snacking, which consists of short bouts of exercise distributed throughout the day, may be an alternative or complementary approach to traditional aerobic exercise in individuals with OSA. In addition, this study aims to be the first randomized controlled trial evaluating the effects of exercise snacking on circadian rhythm and functional capacity in individuals with OSA.

Study Overview

• Status: Not yet recruiting
• Conditions: Physical Activity; Sleep; Circadian Rhythm; Obstructive Sleep Apnea (OSA); Exercise Snacks
• Intervention / Treatment: Behavioral: Aerobic Exercise Training; Behavioral: Exercise Snacking

Detailed Description

Obstructive Sleep Apnea Syndrome (OSA) is a common sleep-related breathing disorder characterized by repeated episodes of partial or complete upper airway obstruction during sleep. It is associated with intermittent hypoxia, sleep fragmentation, and increased risk of cardiovascular and metabolic comorbidities. Emerging evidence also suggests a bidirectional relationship between OSA and circadian rhythm disruption, where each condition may negatively influence the other. Therefore, improving circadian regulation may be an important therapeutic target in OSA management.Exercise is a widely accepted non-pharmacological intervention in OSA due to its potential benefits on sleep-related outcomes and overall health. However, adherence to conventional structured exercise programs may be limited due to time constraints and sustainability issues. Recently, exercise snacking-short bouts of exercise performed throughout the day-has been proposed as a time-efficient and more feasible alternative to traditional exercise approaches. This strategy may improve long-term adherence by integrating physical activity into daily routines without requiring supervised sessions.Despite its potential advantages, evidence regarding the effects of exercise snacking in individuals with OSA is currently limited. In addition, there is a lack of randomized controlled trials comparing exercise snacking with aerobic exercise while also evaluating circadian rhythm-related outcomes in this population.This study is designed as a prospective, single-blind, randomized controlled trial. A total of 39 individuals diagnosed with moderate to severe OSA will be randomly assigned to three groups: aerobic exercise group, exercise snacking group, and control group. The intervention period will last 8 weeks. The aerobic exercise group will perform supervised aerobic and resistance-based training, while the exercise snacking group will perform short, home-based exercise bouts distributed across the day. The control group will continue usual medical care and receive a single session of sleep hygiene education.The study will evaluate the effects of the interventions on circadian rhythm and functional capacity as primary outcomes, and on secondary outcomes including fatigue, muscle strength, body composition, physical activity level, insomnia severity, and quality of life. Assessments will be performed at baseline and after the 8-week intervention period.

• Study Type: Interventional
• Enrollment (Estimated): 39
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Melis Usul, PhD student; Phone Number: +(90)5364667235; Email: melisausul1999@gmail.com
• Study Contact Backup: Name: Gökşen Kuran Aslan, Professor; Phone Number: +(90)5324095246; Email: goksenkuran@yahoo.com

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye)
    • Istanbul University-Cerrahpaşa, Department of Physiotherapy and Rehabilitation, Istanbul, Türkiye
    • Contact: Melis Usul; Phone Number: +(90)5364667235; Email: melisausul1999@gmail.com
    • Principal Investigator: Melis USUL
    • Sub-Investigator: Gökşen Kuran Aslan
    • Sub-Investigator: Esen Kıyan
    • Sub-Investigator: Zeynep Banu Güngör

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Individuals diagnosed with OSAHS (AHI ≥ 15) confirmed by polysomnography, with moderate or severe disease, who have been receiving CPAP therapy for at least 3 months.
• Adults aged 30-65 years.
• No participation in any regular exercise program within the last 6 months.

Exclusion Criteria:

• Individuals with OSAHS and a body mass index (BMI) > 35 kg/m²
• Severe chronic pulmonary disease
• Neurological or musculoskeletal disorders that prevent exercise
• Unstable cardiovascular conditions
• Unstable metabolic conditions
• Severe psychiatric disorders such as bipolar disorder or schizophrenia
• Pregnancy or breastfeeding
• Individuals working night shifts or with schedules that may cause jet lag
• Use of steroid or hormone therapy
• Use of melatonin or sleep-regulating medications within the last 3 months
• Presence of acute infection or inflammation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Aerobic Exercise Group; Aerobic Exercise Training	Behavioral: Aerobic Exercise Training; Participants in the aerobic exercise group will undergo an 8-week supervised aerobic exercise program on a cycle ergometer, performed twice per week. Each session will last approximately 30-45 minutes and will include a 5-minute low-intensity warm-up and a 5-minute cool-down period. Exercise intensity will be set at a moderate level according to the Karvonen method. The main exercise duration will be progressively increased throughout the intervention period: 20 minutes during weeks 1-2, 25 minutes during weeks 3-4, 30 minutes during weeks 5-6, and 35 minutes during weeks 7-8. Participants' heart rate will be monitored during exercise sessions, and perceived exertion will be assessed using the Borg Rating of Perceived Exertion Scale.In addition, all participants will be instructed to perform resistance exercises once per week. The exercises will target the upper extremity, lower extremity, and core muscles and will consist of three different exercises.
Experimental: Exercise Snacks Group; Exercise Snacking	Behavioral: Exercise Snacking; The exercises will be performed by participants at home and supervised by the researcher. Since progression of each exercise will be implemented every two weeks, participants will be scheduled to attend the clinic every two weeks, where the exercises will be demonstrated. Each session will consist of six different exercises (squat, heel raises, marching in place, jumping jacks, upright row, and chest press). Each exercise will be performed for 1 minute, followed by a 1-minute seated rest interval. Thus, each session will last approximately 12 minutes. Exercise progression will be applied every two weeks for each exercise. During the sessions, participants will monitor their heart rate and oxygen saturation. An oxygen saturation level below 90% will be defined as the exercise termination criterion. Participants will be provided with a daily logbook to record completion of exercise snacking sessions.
No Intervention: Control Group (Usual Care); Usual Care

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pittsburgh Sleep Quality Index (PSQI) Total Score	Sleep quality assessed using the Pittsburgh Sleep Quality Index. Total scores range from 0 to 21, with higher scores indicating poorer sleep quality.	From baseline to the end of the intervention at 8 weeks
Epworth Sleepiness Scale (ESS) Total Score	Daytime sleepiness will be assessed using the Epworth Sleepiness Scal (ESS).Scores ≥10 indicate excessive daytime sleepiness.	From baseline to the end of the intervention at 8 weeks
Morningness-Eveningness Questionnaire (MEQ) Total Score	Circadian rhythm preference will be assessed using the Morningness-Eveningness Questionnaire (MEQ).The questionnaire consists of 19 items evaluating sleep-wake preferences and chronotype.Higher scores indicate morningness, whereas lower scores indicate eveningness.	From baseline to the end of the intervention at 8 weeks
Serum Cortisol Level	Fasting morning serum cortisol concentration measured by chemiluminescent immunoassay.	From baseline to the end of the intervention at 8 weeks
Serum Thyroid-Stimulating Hormone (TSH) Level	Fasting morning serum TSH concentration measured by chemiluminescent immunoassay.	From baseline to the end of the intervention at 8 weeks
Functional Capacity	Functional capacity will be assessed using the 6-Minute Walk Test (6MWT) according to American Thoracic Society criteria. Walking distance covered within 6 minutes will be recorded in meters. Higher values indicate better functional capacity.	From baseline to the end of the intervention at 8 weeks
Total Sleep Time (Sleep Diary)	Total sleep time will be assessed subjectively using a sleep diary based on the Consensus Sleep Diary (CSD). Participants will complete the diary for 7 consecutive days at baseline and at week 8. Total sleep time will be recorded in minutes.	From baseline to the end of the intervention at 8 weeks
Total Sleep Time (Wearable Device)	Total sleep time will be objectively assessed using a Polar Unite wearable activity tracker with Sleep Plus Stages™ algorithm. Measurements will be collected over 3 consecutive nights at baseline and at week 8. Total sleep time will be expressed in minutes.	From baseline to the end of the intervention at 8 weeks
Sleep Efficiency (Wearable Device)	Sleep efficiency will be assessed using a Polar Unite wearable activity tracker with Sleep Plus Stages™ algorithm. Measurements will be collected over 3 consecutive nights at baseline and at week 8. Sleep efficiency will be expressed as percentage (%).	From baseline to the end of the intervention at 8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insomnia Severity	Insomnia severity will be assessed using the Insomnia Severity Index (ISI). The ISI consists of 7 items scored from 0 to 4, with a total score ranging from 0 to 28. Higher scores indicate greater insomnia severity. Scores ≥10 indicate clinically significant insomnia.	From baseline to the end of the intervention at 8 weeks
Waist Circumference (cm)	Waist circumference measured using a non-elastic tape measure.	From baseline to the end of the intervention at 8 weeks
Hip Circumference (cm)	Hip circumference measured using a non-elastic tape measure.	From baseline to the end of the intervention at 8 weeks
Neck Circumference (cm)	Neck circumference measured using a non-elastic tape measure.	From baseline to the end of the intervention at 8 weeks
Muscle Mass (kg)	Muscle mass assessed using bioelectrical impedance analysis (BIA).	From baseline to the end of the intervention at 8 weeks
Body Fat Percentage (%)	Body fat percentage assessed using bioelectrical impedance analysis (BIA).	From baseline to the end of the intervention at 8 weeks
Bone Mass (kg)	Bone mass assessed using bioelectrical impedance analysis (BIA).	From baseline to the end of the intervention at 8 weeks
Body Water Percentage (%)	Body water percentage assessed using bioelectrical impedance analysis (BIA).	From baseline to the end of the intervention at 8 weeks
Fatigue Severity	Fatigue severity will be assessed using the Fatigue Severity Scale (FSS). The FSS consists of 9 items scored from 1 to 7. Higher scores indicate greater fatigue severity. Mean scores ≥4 indicate clinically significant fatigue.	From baseline to the end of the intervention at 8 weeks
Peripheral Muscle Strength	Peripheral muscle strength (quadriceps, biceps brachii, and handgrip strength) will be assessed using a hand-held dynamometer and handgrip dynamometer. Higher values indicate greater muscle strength.	From baseline to the end of the intervention at 8 weeks
Physical Activity Level	Physical activity level will be assessed using a pedometer. Average daily step count (steps/day) will be recorded. Higher values indicate greater physical activity.	From baseline to the end of the intervention at 8 weeks
Health-related quality of life (Functional Outcomes of Sleep Questionnaire, FOSQ)	Quality of life will be assessed using the Functional Outcomes of Sleep Questionnaire (FOSQ). The questionnaire consists of 26 items with total scores ranging from 4 to 16. Lower scores indicate greater impairment in sleep-related quality of life.	From baseline to the end of the intervention at 8 weeks
Patient Global Impression of Change	Perceived clinical improvement will be assessed using the Patient Global Impression of Change (PGIC). The scale ranges from 1 (very much improved) to 7 (very much worse). Lower scores indicate greater perceived improvement.	At the end of the intervention (8 weeks)

Collaborators and Investigators

• Sponsor: Istanbul University - Cerrahpasa
• Investigators: Principal Investigator: MELİS USUL, Istanbul University - Cerrahpasa; Study Director: Gökşen Kuran Aslan, Professor, Istanbul University - Cerrahpasa; Study Chair: Esen Kıyan, Professor, Istanbul University Faculty of Medicine; Study Chair: Zeynep Banu Güngör, Professor, Istanbul University - Cerrahpasa

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): February 1, 2028

Study Registration Dates

• First Submitted: May 31, 2026
• First Submitted That Met QC Criteria: June 3, 2026
• First Posted (Actual): June 8, 2026

Study Record Updates

• Last Update Posted (Actual): June 8, 2026
• Last Update Submitted That Met QC Criteria: June 3, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Obstructive Sleep Apnea; exercise training; circadian rhythm; exercise snacks
• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Respiration Disorders; Sleep Wake Disorders; Apnea; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Apnea Syndromes; Behavior; Sleep Apnea, Obstructive; Motor Activity
• Other Study ID Numbers: 3RQX7PDq

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No