ABSTRACT

　The purpose of this study was to evaluate if cerebrovascular responsiveness to hypercapnia determined by a brief exposure to a high level of CO₂ gas mixture is associated with arterial stiffness and aerobic capacity in young healthy adults. Twenty-four college students participated in this study. The study of cerebrovascular responsiveness to hypercapnia, arterial stiffness and aerobic capacity were conducted. To examine cerebrovascular responsiveness to hypercapnia, they wore a mask connected with 2-way valve and they were exposed without them knowing to a 10% CO₂ gas mixture just for 2 breaths to induce brief hypercapnia. To evaluate cerebrovascular response to hypercapnia, changes in total hemoglobin (tHb) on the forehead using near-infrared spectroscopy (NIRS) and end-tidal PCO₂ (PETCO₂) using a CO₂ analyzer were measured continuously throughout the examination. The cerebrovascular responsiveness to hypercapnia was assessed as changes in tHb over changes in PETCO₂. Arterial stiffness was assessed by the cardio-ankle vascular index (CAVI). Peak O₂ uptake was measured to evaluate aerobic capacity. Following the exposure to hypercapnic gas mean blood pressure and SaO₂ were not affected, while heart rate was increased. By the exposure to hypercapnic gas PETCO2 was increased from 38±4mmHg to 51±3mmHg, and tHb over the forehead was increased by 0.012±0.012mM. Among these subjects there was a negative correlation between CAVI and aerobic capacity (r=-0.47, P<0.05). On the other hand, there was no correlation between cerebrovascular responsiveness to hypercapnia and aerobic capacity or CAVI. It was concluded that the cerebrovascular responsiveness to hypercapnia determined by a brief exposure to high level of CO₂ and by NIRS is not associated with aerobic capacity or arterial stiffness in young healthy adults.

DESCENTE SPORTS SCIENCE Vol.38/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE