Physical Functions and Lifestyle Behaviours in Post-COVID-19 Syndrome Based on Circadian Rhythms
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- This is an observational study: the protocol does not assign a study treatment.
- Who it may be relevant to
- Registry conditions: Post-COVID-19 Syndrome. Basic parameters: 18 years — 65 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Turkey (Türkiye)
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Comparison of Respiratory Muscle Strength, Physical Activity Level, and Dietary Habits in Individuals With Post-COVID-19 Syndrome Having Different Circadian Rhythms
Overview
Post-COVID-19 syndrome is associated with persistent symptoms such as fatigue, reduced physical activity, and impaired respiratory function. Circadian rhythm differences (chronotype) may influence lifestyle behaviors including physical activity, nutrition, and sleep patterns. This observational cross-sectional study aims to compare respiratory muscle strength, physical activity levels, and nutritional habits among individuals with post-COVID-19 syndrome according to their chronotype (morning, intermediate, and evening types). Additionally, genetic analysis of the CLOCK gene polymorphism will be performed to support objective evaluation of circadian rhythm differences. The findings of this study may help to better understand the role of circadian rhythm in post-COVID-19 syndrome and contribute to the development of individualized rehabilitation and lifestyle interventions.
Detailed description
Post-COVID-19 syndrome is characterized by persistent symptoms such as fatigue, reduced exercise tolerance, and impaired respiratory function following acute SARS-CoV-2 infection. Emerging evidence suggests that circadian rhythm disruption may play a role in the pathophysiology of these symptoms by affecting metabolic regulation, hormonal balance, sleep quality, and physical performance.
Circadian rhythm varies between individuals and is commonly classified into chronotypes as morning, intermediate, and evening types. These chronotypes are associated with differences in daily activity patterns, nutritional behaviors, and physiological performance.
The aim of this observational cross-sectional study is to compare respiratory muscle strength, physical activity levels, nutritional habits, sleep quality, fatigue perception, and gastrointestinal symptoms in individuals with post-COVID-19 syndrome according to their chronotype.
Participants aged 18-65 years with a confirmed diagnosis of post-COVID-19 syndrome will be included. Chronotype will be assessed using the Munich Chronotype Questionnaire (MCTQ). Respiratory muscle strength will be evaluated using maximal inspiratory and expiratory pressures (MIP/MEP), and dynamic respiratory parameters will be assessed using a POWERbreathe device. Respiratory muscle endurance will be measured using threshold loading protocols.
Physical activity levels will be assessed using the International Physical Activity Questionnaire (IPAQ), while nutritional intake will be evaluated using 24-hour dietary recall. Sleep quality, fatigue severity, and gastrointestinal symptoms will be assessed using validated questionnaires.
In addition, blood samples will be collected for genetic analysis of the CLOCK gene polymorphism (rs1801260) using PCR-RFLP techniques to provide an objective assessment of circadian rhythm differences.
This study is expected to provide comprehensive insight into the relationship between circadian rhythm and functional, behavioral, and physiological outcomes in post-COVID-19 syndrome, and may contribute to the development of individualized rehabilitation strategies.
Primary outcome measures
- Respiratory Muscle Strength [Time frame: Time Frame: Day 1]
- Dynamic respiratory muscle strength [Time frame: Time Frame: Day 1]
- Respiratory muscle endurance [Time frame: Time Frame: Day 1]
Secondary outcome measures (7)
- Physical Activity Level [Time frame: Time Frame: Day 1]
- Dietary Intake [Time frame: Time Frame: Day 1]
- Chronotype Classification [Time frame: Time Frame: Day 1]
- Fatigue Severity [Time frame: Time Frame: Day 1]
- Gastrointestinal Symptoms [Time frame: Time Frame: Day 1]
- Sleep Quality [Time frame: Time Frame: Day 1]
- Classificationof human faeces forms [Time frame: Time Frame: Day 1]
Eligibility criteria
Inclusion criteria
- Diagnosed with Post-COVID-19 Syndrome
- Aged between 18-65 years
- Able to read and understand Turkish
- Voluntary participation
- Classified as Post-Covid Functional Status Scale (PCFS) grade 2-3
- Clinically stable condition
- No uncontrolled comorbidities (e.g., hypertension, diabetes under control)
- No orthopedic or neurological conditions affecting exercise testing
Exclusion criteria
- Recent myocardial infarction or pulmonary embolism
- Severe uncontrolled chronic diseases
- Neurological or orthopedic conditions limiting mobility
- Psychiatric or neurological disorders affecting cooperation or test compliance
- Inability to complete assessments
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Observational model
- Other
Study locations
Turkey (Türkiye) · 1 center
- Hacettepe University Faculty of Physical Therapy and Rehabilitation — Ankara
Publications
- Suwazono Y, Dochi M, Sakata K, Okubo Y, Oishi M, Tanaka K, Kobayashi E, Kido T, Nogawa K. A longitudinal study on the effect of shift work on weight gain in male Japanese workers. Obesity (Silver Spring). 2008 Aug;16(8):1887-93. doi: 10.1038/oby.2008.298. Epub 2008 Jun 5. PMID 18535539
- Voigt RM, Forsyth CB, Green SJ, Engen PA, Keshavarzian A. Circadian Rhythm and the Gut Microbiome. Int Rev Neurobiol. 2016;131:193-205. doi: 10.1016/bs.irn.2016.07.002. Epub 2016 Sep 6. PMID 27793218
Identifiers
NCT: NCT07545499 · FTREK25/33