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

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.