Comparative Analysis of Heart Rate Variability in Athletes and Sedentary Adults

Thesis Abstract

Heart rate variability (HRV) serves as a crucial non-invasive marker of autonomic nervous system functioning and cardiovascular health, yet limited comparative data exist on how HRV differs between athletes engaged in high-intensity physical training and sedentary adults with minimal physical activity. This study aims to systematically compare HRV measures in these two populations, elucidating differences attributable to physical activity levels and their implications for autonomic regulation and cardiovascular resilience. The specific objectives are to quantify and contrast time-domain, frequency-domain, and non-linear HRV parameters between athletes and sedentary adults; to examine associations between HRV indices and variables such as age, gender, and body mass index (BMI); and to evaluate the predictive value of HRV measures for cardiovascular health outcomes within and across groups. Grounded in the autonomic nervous system's regulatory framework and employing the Polyvagal Theory and the Neurovisceral Integration Model as theoretical foundations, the research hypothesizes that athletes will exhibit significantly higher HRV indices, reflecting enhanced parasympathetic activity compared to sedentary counterparts. This cross-sectional comparative study employs a quantitative research design and targets a diverse adult population aged 20–35 years from two national sports centers and general community settings, totaling 200 participants (100 athletes and 100 sedentary adults), selected via stratified random sampling. Data collection involves standardized electrocardiogram (ECG) recordings of five-minute resting HRV using the Biopac Student Lab system, complemented by demographic and health questionnaires. Validity and reliability of the ECG equipment conform to international standards, with calibration procedures verified prior to data collection. Data analysis is conducted using SPSS version 27, applying descriptive statistics to summarize HRV measures, independent t-tests and Mann-Whitney U tests to compare groups, and multiple regression analyses to explore associations with demographic variables, controlling for potential confounders. The analysis anticipates revealing that athletes display significantly elevated HRV values across the time-domain (e.g., RMSSD), frequency-domain (e.g., high-frequency power), and non-linear measures (e.g., Poincaré plot parameters), confirming greater parasympathetic modulation. Conversely, sedentary adults are expected to show reduced HRV indices suggestive of diminished autonomic adaptability. These differences are hypothesized to be consistent irrespective of age and gender, after adjusting for BMI. Furthermore, the findings are anticipated to demonstrate strong correlations between higher HRV and favorable cardiovascular markers, indicating that HRV can serve as a reliable indicator of autonomic health. The expected contribution of this research resides in filling the existing knowledge gap regarding the impact of sustained physical activity on HRV in young adults and substantiating HRV's utility as a biomarker for cardiovascular resilience in diverse populations. It advances the application of the Polyvagal and Neurovisceral models in understanding autonomic regulation among active versus sedentary individuals. The study's main conclusion underscores the importance of regular physical activity in promoting autonomic health, with potential implications for developing targeted interventions aimed at improving cardiovascular outcomes. Based on the findings, recommendations include advocating for increased physical activity in sedentary populations, integrating HRV monitoring into routine health assessments, and conducting longitudinal studies to elucidate causality and the long-term benefits of physical fitness on autonomic function. Future research avenues proposed encompass exploring psychosocial factors influencing HRV and assessing the effects of specific training regimens on autonomic regulation.