Spontaneous baroreflex sensitivity in (pre)adolescents

Objective To present normal spontaneous baroreflex sensitivity (BRS) values and investigate the influence of posture, sex, age, pubertal stage, body mass index (BMI), , and physical activity level on BRS in (pre)adolescents. BRS is a sensitive measure of both sympathetic and parasympathetic cardiovascular regulation that may help detect early subclinical autonomic dysfunction. Design A cross-sectional cohort study in a large sample of 10-13-year-old Dutch (pre)adolescents from the general population. Methods Short-term spontaneous BRS was determined non-invasively by Portapres in both the supine and standing position. BRS was calculated by power spectral analysis using the discrete Fourier method (frequency band 0.07-0.14 Hz). Univariate statistical methods and multiple regression analyses were applied. Results BRS in a standing position was lower than in a supine position (9.0 +/- 4.9 versus 15.3 +/- 9.1 ms/mmHg; t = 27.8, P < 0.001). Girls had lower BRS values than boys in both postures (supine 14.3 +/- 8.7 versus 16.4 +/- 9.4 ms/mmHg, beta = 0.12, P < 0.001; standing 8.4 +/- 4.4 versus 9.5 +/- 5.4 ms/mmHg, beta = 0.08, P = 0.012), independent of age, pubertal stage, BMI, and physical activity. Lower limits (P2.5) for normal BRS values in supine and standing positions were for girls 3.6 and 2.2 ms/mmHg and for boys 3.9 and 2.5 ms/mmHg, respectively. BRS declined with age in the standing position (beta = -0.13, P < 0.001). In obese (pre)adolescents, BMI was negatively associated with BRS during standing (Kendall's tau = -0.26, P = 0.010). Conclusion The BRS of (pre)adolescents was negatively related to female sex, age, and obesity. A reduced BRS in obese (pre)adolescents might be a candidate predictor of future cardiovascular health, and therefore warrants further exploration.