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

Thesis Abstract

Cardiovascular regulation during adolescence is a critical determinant of long-term health outcomes and is significantly influenced by autonomic nervous system activity, which can be maladaptive due to stress, sedentary lifestyles, and emerging psychosocial challenges. Despite the increasing use of biofeedback techniques to enhance autonomic regulation, there is limited empirical evidence tailored specifically to adolescent populations, particularly regarding the design and efficacy of structured interventions aimed at improving cardiovascular homeostasis. This study aims to develop, implement, and evaluate a targeted biofeedback intervention to enhance cardiovascular regulation among adolescents aged 13 to 18 years. The specific objectives are to (1) design a comprehensive biofeedback protocol grounded in the biopsychosocial model and relevant physiological theories such as the Polyvagal Theory and the Neurovisceral Integration Model; (2) assess the feasibility and acceptability of the intervention within school-based settings; and (3) evaluate the intervention’s effectiveness using physiological, psychological, and behavioral outcome measures. Employing a mixed-methods quasi-experimental research design, the study will recruit a representative sample of 120 adolescents randomly assigned into intervention and control groups, ensuring demographic diversity and capturing varying baseline autonomic function levels. Data collection instruments include portable biofeedback devices that monitor heart rate variability (HRV) as the primary physiological indicator of cardiovascular regulation, validated self-report questionnaires assessing perceived stress and emotional regulation, and behavioral assessments of lifestyle factors such as physical activity levels. Data collection occurs at pre-intervention, post-intervention (after 8 weeks), and follow-up (3 months post-intervention). Quantitative data will be analyzed through multivariate analysis of covariance (MANCOVA) to detect differences between groups over time, complemented by regression analysis to identify predictors of improved regulation. Thematic analysis will be employed for qualitative feedback on participant experiences and perceived benefits. The intervention's effect will be evaluated against baseline measures, with the hypothesis that adolescents receiving the biofeedback protocol will demonstrate significant improvements in HRV, reductions in perceived stress, and enhanced emotion regulation compared to controls. Anticipated findings include statistically significant increases in HRV indices correlating with improved autonomic balance, along with reductions in stress and maladaptive emotional responses. These findings are expected to support the hypothesis that biofeedback interventions can effectively enhance physiological and psychological resilience in adolescents. Theoretically, the study will contribute to extending existing models of autonomic regulation by integrating biofeedback feedback loops within the context of adolescent development and psychosocial stressors. This research offers a novel, evidence-based framework for school-based health promotion initiatives and provides a foundation for future longitudinal studies on cardiovascular health trajectories. The study underscores the importance of early preventive strategies by demonstrating the feasibility and effectiveness of non-pharmacological, biofeedback-based programs in enhancing cardiovascular health in youth populations. Its contributions to applied physiology include validated protocols for biofeedback application in adolescent settings and nuanced understanding of the interaction between physiological regulation and psychosocial variables during critical developmental periods. The main conclusion emphasizes that structured biofeedback interventions, when properly tailored, are practical, acceptable, and capable of producing meaningful physiological and psychological benefits. Recommendations include integrating biofeedback into school health curricula, establishing training modules for practitioners, and conducting larger-scale longitudinal trials to assess sustained outcomes. Future research should explore digital adaptation of biofeedback devices and the role of family and community support in amplifying intervention benefits, advancing personalized approaches to adolescent cardiovascular health promotion.