Design and evaluate a biofeedback intervention to improve cardiovascular variability in adolescents

Thesis Abstract

Cardiovascular variability is a crucial marker of autonomic nervous system function and overall cardiovascular health, particularly during adolescence—a developmental period marked by physiological and psychological changes that can influence cardiovascular regulation. Despite the recognized importance of maintaining healthy autonomic function, adolescents often exhibit reduced heart rate variability (HRV), which is associated with increased risk for future cardiovascular and mental health disorders. This study aims to design, implement, and evaluate a targeted biofeedback intervention aimed at enhancing cardiovascular variability among adolescents aged 13 to 17 years. The specific objectives are to develop a biofeedback protocol tailored to adolescent needs, assess its feasibility and acceptability, and determine its effect on HRV parameters over a three-month period. The research adopts a quasi-experimental pretest-posttest design involving 120 adolescents randomly assigned into intervention and control groups, recruited from secondary schools in an urban area. The intervention group will participate in bi-weekly biofeedback sessions using the HeartMath emWave system, integrated with adolescent-centered cognitive-behavioral strategies, while the control group will receive standard health education. Data collection will employ a combination of validated HRV measurement devices (e.g., EKG-based heart rate monitors), psychological questionnaires (e.g., the Perceived Stress Scale), and semi-structured interviews to assess participants’ experiences. Data validity and reliability will be established through calibration protocols and pilot testing of questionnaires, with Cronbach’s alpha exceeding 0.85 for all scales. Quantitative data will be analyzed using repeated measures ANOVA to compare HRV indices (such as SDNN, RMSSD, and LF/HF ratio) within and between groups over time. Regression analyses will explore the predictors of changes in HRV, considering variables like baseline stress levels and adherence to the intervention. Thematic analysis will be employed for qualitative interview data to elucidate participants’ perceptions and subjective outcomes of the intervention. The theoretical underpinning for the study is based on the Neurovisceral Integration Model, which links HRV to emotional regulation and cognitive processes, and the Transactional Model of Stress and Coping, informing the intervention’s focus on autonomic and psychological regulation. It is anticipated that the biofeedback intervention will lead to statistically significant improvements in HRV measures, indicating enhanced autonomic regulation, alongside reductions in perceived stress levels. These findings are expected to demonstrate the efficacy of biofeedback as a non-pharmacological intervention to promote cardiovascular health in adolescents, filling a noticeable gap in youth-focused autonomic regulation research. The study’s contribution to knowledge lies in providing empirical evidence for scalable biofeedback protocols tailored to adolescent populations, integrating physiological and psychological outcomes, guided by established theoretical frameworks. The main conclusion is that structured biofeedback training can effectively improve cardiovascular variability in adolescents, with broader implications for early prevention of cardiovascular and stress-related health issues. Based on the findings, it is recommended that schools and health practitioners incorporate biofeedback techniques into adolescent health programs, and further longitudinal studies are suggested to examine the sustained impacts over extended periods. Overall, this research advances understanding of autonomic regulation interventions in adolescence, advocating for integrating biofeedback methods into holistic health promotion strategies during this critical developmental stage.