The Effect of Exercise in the Mild Hypoxic Condition on Arterial Stiffness

The purpose of this study is to investigate the effect of exercise and normobaric hypoxia exposure corresponding to mild altitude on arterial stiffness. In a cross-over design, 13 young (19.6±1.3years) healthy males were asked to perform the ergometer exercise twice in hypoxia and control (no-treatment) condition with a week interval. Subjects were assigned to the hypoxia condition group breathed hypoxic air corresponding to 3150m altitude condition for 1 hour through the hypoxic control device (Altrainer, SMTEC Sports & Medical Technologies SA, Nyon, Switzerland). Each subject performed 15m in-incremental bicycle exercise till their heart rate reached 70% heart rate reserve level. Arterial stiffness was measured by VaSera CAVI instrument Fukuda Denshi Co., Ltd., Tokyo, Japan) at rest, immediately after exercise and recovery 15minute. Two indexes of arterial stiffness (cardio ankle vascular index-CAVI, ankle brachial index-ABI) were obtained. Arterial oxygen saturation was also measured by pulse oximetry. The results are as follows: 1. Arterial oxygen saturation of hypoxia group at rest, immediately after exercise and recovery 15minute was significantly lower than control group (p.05). 2. Cardio-ankle vascular index (CAVI) measured at recovery 15 min was significantly higher in hypoxia group than in control group (p.05). 3. Ankle Brachial index (ABI) showed no significant difference between groups at all the time points. These findings suggest that hypoxic condition at recovery time point can more affect the aorta and systemic arterial stiffness represented by CAVI than sea level condition during exercise.