Association of Severe Obesity, Hypertension, and Physical Activity with 24 h Heart Rate Variability in Adults

Background: Heart rate variability (HRV), the physiological variation between consecutive heartbeats and a non-invasive marker of autonomic regulation, is associated with cardiovascular health. This retrospective cross-sectional study investigated the associations of severe obesity, hypertension, and physical activity with 24 h HRV in patients undergoing evaluation for bariatric surgery. Methods: A total of 1048 individuals were classified according to obesity class, hypertension diagnosis, and physical activity level. Results: Severe obesity was associated with lower 24 h HRV indices (p < 0.001) and higher odds ratio of hypertension (OR 2.04 1.60–2.63) and antihypertensive medication use (OR 1.98 1.53–2.58) compared to class II obesity. Hypertension was associated with lower HRV indices (p < 0.001), higher odds of diabetes (OR 4.20 2.88–6.12) and dyslipidemia (OR 2.85 2.17–3.74), greater use of related medications (OR 3.53 2.18–5.70) and 2.96 1.99–4.40), respectively), and lower physical activity (OR 0.64 0.47–0.87). Physical activity was associated with higher 24 h HRV indices (p < 0.001) and lower odds of hypertension (OR 0.64 0.47–0.87) and antihypertensive medication use (OR 0.70 0.50–0.97). Conclusions: Severe obesity and hypertension were associated with reduced 24 h HRV, whereas physical activity was associated with more favorable HRV parameters in adults undergoing evaluation for bariatric surgery, supporting its relevance for cardiovascular health in this population.