Association between cardiorespiratory fitness and pediatric primary hypertension: a case-control study in China.

Objectives: This study aimed to investigate the association between cardiorespiratory fitness (CRF) and the risk of primary hypertension in children and adolescents, and to explore the relationship between CRF and hemodynamic parameters.

Methods: In this single-center case-control study, 972 participants aged 10-17 years (352 hypertension cases, 620 controls) were included. CRF was quantified as peak oxygen uptake (VO2peak) using a validated equation derived from treadmill tests. Logistic regression models, restricted cubic splines, and subgroup analyses were employed to assess CRF-hypertension associations, adjusted for age, sex, height, and overweight/obesity. Multivariate linear regression evaluated correlations between CRF and blood pressure or heart rate parameters.

Results: After adjustment, each 5 ml/kg/min increment in CRF was associated with a 30% reduction in hypertension risk [odds ratio (OR) 0.70, 95% confidence interval (95% CI) 0.63-0.78, P < 0.001]. Participants with CRF less than 44.7 ml/kg/min exhibited a 3.35-fold higher hypertension risk than those with CRF at least 44.7 ml/kg/min (OR 3.35, 95% CI 2.21-5.16, P < 0.001). Subgroup analyses confirmed consistency across age, sex, height, and BMI status (P for interaction > 0.05). Notably, overweight/obese individuals showed a 35% risk reduction per 5 ml/kg/min CRF improvement (OR 0.65, 95% CI 0.57-0.74). CRF was inversely correlated with systolic, diastolic, and mean arterial blood pressure, resting and peak heart rate, peak SBP/DBP, and rate-pressure product (all P < 0.05).

Conclusion: Higher CRF is independently associated with reduced primary hypertension risk in children and adolescents, highlighting its role as a modifiable protective factor, particularly among overweight/obese youth. These findings support CRF-enhancing interventions as a preventive strategy against pediatric hypertension.