Physical Functions and Lifestyle Behaviours in Post-COVID-19 Syndrome Based on Circadian Rhythms

NCT07545499 | Recruiting

• 1 other identifier: FTREK25/33
• Study Type: observational
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Post-COVID-19 Syndrome

Keywords

Circadian Rhythm; Chronotype; Respiratory Muscle Strength; Physical Activity; Nutrition; Post-COVID; Long COVID; CLOCK Gene; Genetic Polymorphism

Outcome Measures

Primary Outcomes (3)

• Respiratory Muscle Strength

  Maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP) values will be recorded with mouth pressure device.

  Time Frame: Day 1

• Dynamic respiratory muscle strength

  Respiratory muscle strength index (S index) will be assessed using a portable POWERbreathe K5 device.

  Time Frame: Day 1

• Respiratory muscle endurance

  Respiratory muscle endurance test at constant threshold load will be used.

  Time Frame: Day 1

Secondary Outcomes (7)

• Physical Activity Level

  Time Frame: Day 1

• Dietary Intake

  Time Frame: Day 1

• Chronotype Classification

  Time Frame: Day 1

• Fatigue Severity

  Time Frame: Day 1

• Gastrointestinal Symptoms

  Time Frame: Day 1

Study Arms (2)

Morning Types (Larks)

People who wake up early, feel most energetic in the morning, and reach their peak performance early in the day.

Evening Types (Owls)

People who stay up late, struggle with early mornings, and reach their peak functional capacity in the late afternoon or evening.

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study population consists of post-COVID-19 syndrome patients aged 18-65 years who are referred to the Hacettepe University Cardiopulmonary Rehabilitation Unit. Participants will be classified into morning-type and evening-type chronotypes.

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Hacettepe University: lead

Study Sites (1)

Hacettepe University Faculty of Physical Therapy and Rehabilitation

Ankara, Altindağ, 06100, Turkey (Türkiye)

RECRUITING

Related Publications (2)

• 2. Suwazono Y, Dochi M, Sakata K, Okubo Y, Oishi M, Tanaka K, et al. A longitudinal study on the effect of shift work on weight gain in male Japanese workers. Obesity (Silver Spring). 2008;16(8):1887-93.

  BACKGROUND

• 1. Voigt RM, Forsyth CB, Green SJ, Engen PA, Keshavarzian A. Circadian Rhythm and the Gut Microbiome. Int Rev Neurobiol. 2016;131:193-205.

  BACKGROUND

MeSH Terms

Conditions

Post-Acute COVID-19 Syndrome; Motor Activity

Condition Hierarchy (Ancestors)

COVID-19; Pneumonia, Viral; Pneumonia; Respiratory Tract Infections; Infections; Virus Diseases; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Lung Diseases; Respiratory Tract Diseases; Post-Infectious Disorders; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Behavior

Central Study Contacts

Ebru Çalık, Professor

CONTACT

+905442850087; ecalik85@gmail.com

Study Design

• Study Type: observational
• Observational Model: OTHER
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: April 14, 2026
• First Posted: April 22, 2026
• Study Start: May 22, 2025
• Primary Completion (Estimated): August 22, 2026
• Study Completion (Estimated): May 22, 2027
• Last Updated: April 22, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)