Abstract
Vascular aging involves reduced endothelial function, a key factor in cardiovascular diseases. Intermittent hypoxia may improve endothelial function and cardiorespiratory fitness (CRF), but its effects in elderly individuals, especially in the mid-term, have not yet been studied. This randomized, single-blind controlled trial aimed to investigate whether an 8-week intermittent hypoxic conditioning (IHC) program may enhance flow-mediated dilation (FMD) and CRF in elderly individuals. Twenty-six participants (60-80 year-old) were assigned to either the IHC (n = 12) or the control group (CTL: n = 14). The IHC group underwent 24 passive intermittent hypoxia sessions (3/week). Brachial artery FMD, cardiopulmonary exercise testing (CPET), and ambulatory 24-h blood pressure were assessed at baseline (Pre), immediately post-intervention (Post 1), and 2 months later (Post 2). FMD showed a trend toward improvement in the IHC group, being significant when normalized for baseline artery diameter (p = 0.023; η(p) (2) = 0.150) between Pre and Post 2. Peak ventilation during CPET increased from Pre to Post 1 (p = 0.021), with no other significant CRF changes. Daytime systolic blood pressure decreased by 6 mmHg (p = 0.070, η(p) (2) = 0.105). No significant alterations in these outcomes were observed in the CTL group (p > 0.05). Moderate IHC enhanced mid-term endothelial function, suggesting potential to mitigate age-related vascular decline.