Systemic Vascular Changes in Healthy Children and Adolescents during Short-term Simulated Altitude Exposure

Background: The effect of normobaric hypoxia on the cardiovascular system of children is currently insufficiently researched. The hypoxic response of the systemic vasculature has only been researched in adults where central arterial stiffness appears to increase while the opposite occurs peripherally.

Methods: This prospective study included healthy children aged 8 to 18. Children were evaluated under normoxia at 679 m ASL (corresponding to FiO₂ 19.6%) and under normobaric hypoxia (FiO₂ 13.6%, simulating 3,500 m ASL) with 30 minutes exposure time before the examination. Brachial and central blood pressure (BBP, CBP), heart rate (HR), augmentation index (AIx), carotid–femoral pulse-wave velocity (PWV), and aging index (AI) were measured. In addition, retinal vessel analysis was performed (central retinal venular/arteriolar equivalents [CRVE, CRAE] ratio). Statistical analyses included the Wilcoxon signed-rank test for paired samples (Table 1).

Results: Twenty-three children completed the study (median 12 years; 12 males/11 females). While HR (median normoxia 70, median hypoxia 83, p = 0.002) and diastolic CBP increased, systolic CBP and BBP remained unchanged. PWV increased while AIX and AI decreased significantly. In addition, the central retinal vessel diameters increased (both CRAE and CRVE), while the ratio remained unchanged.

Conclusion: In healthy children and adolescents, a simulated altitude of 3,500 m ASL is associated with increased HR and stable BP. Central arterial stiffness increases while peripherally, arterial and venous vasodilation occurs. In the future, we plan to evaluate children with congenital heart defects who are at risk for adverse when traveling at high altitudes, to enable medical providers to determine potential travel restrictions more adequately in the future.

Publication History

Article published online:
11 February 2025