22–23 Jul 2026
Heidelberg Congress Center
Europe/Berlin timezone

Sedentary Behavior Is Associated with Impaired Cardiac Parasympathetic Modulation in Patients with Stage III–IV Colorectal Cancer: A Pilot Study

23 Jul 2026, 11:45
1h 15m
Heidelberg Congress Center ( Heidelberg Congress Center )

Heidelberg Congress Center

Heidelberg Congress Center

Czernyring 20 69115 Heidelberg Germany
1 - Scientific Poster Poster Session

Speaker

Lilian Messias Sampaio Brito (School of Physical Education and Sport, University of Sao Paulo)

Description

Colorectal cancer (CRC) and its treatment are frequently associated with autonomic nervous system (ANS) dysregulation, characterized by alterations in heart rate variability (HRV) and insufficient levels of physical activity (PA). This cross-sectional, single-center observational study (Phase 1) evaluated patients with Stage III–IV CRC from the Abdominal Surgery Service of Erasto Gaertner Hospital over a 9-month follow-up period. We investigated the association between objectively measured PA, assessed via accelerometry (ActiGraph GT9X), and HRV temporal-domain parameters derived from RR interval analysis (Polar V800). Eight patients of both sexes were included, with a mean age of 51 ± 7.7 years. Accelerometry provided data on Sedentary Time (ST) and Moderate-to-Vigorous Physical Activity (MVPA). ST ≤ 99 counts/min and MVPA ≥ 1952 counts/min were considered, with analyses conducted for total time, weekdays, and weekends. The median ST was 387 (217–468) minutes per day, representing 67.2% ± 9.9% of wear time. Median MVPA was 74 (28–195) minutes per day, corresponding to only 1.7% ± 2.1%, indicating a low overall PA level. The mean resting heart rate (HR) was 77 ± 11.2 bpm. A strong negative correlation was found between ST and RMSSD (root mean square of successive differences), a marker of parasympathetic activity (r = –0.74; p = 0.005), suggesting that higher sedentary time is associated with poorer parasympathetic autonomic modulation. No significant associations were observed between MVPA and HRV parameters.In conclusion, the high sedentary time observed in patients with CRC is strongly associated with reduced cardiac parasympathetic modulation. These findings underscore the importance of interventions aimed at reducing sedentary behavior to improve autonomic regulation and potentially enhance prognosis and quality of life in this population.

Keywords

colorectal cancer; physical activity; sedentary behavior; heart rate variability.

Abstract submitters declaration yes
Conflict of Interest & Ethical Approval yes

Author

Lilian Messias Sampaio Brito (School of Physical Education and Sport, University of Sao Paulo)

Co-authors

Prof. Anderson Zampier Ulbrich (Federal University of Parana) Prof. Telma Fátima da Cunha Moraes (School of Physical Education and Sport, University of Sao Paulo) Dr Gabriel Bernardo de Assis Galhardo (Erasto Gaertner Hospital) Dr Giovanni Zenedin Targa (Erasto Gaertner Hospital) Prof. Thamires Gabrielly dos Santos Coco (Research Group on Physical Activity and Quality of Life, Pontifical Catholic University of Parana) Prof. Patrícia Chakur Brum (School of Physical Education and Sport and Dept of Physiology and Biophysics, Institute of Biomedical Sciences University of Sao Paulo)

Presentation materials

There are no materials yet.