Comparing Vascular Responses to Aerobic Exercise With and Without Blood Flow Restriction in Young and Older Adults

Aging is a major risk factor for cardiovascular disease (CVD), contributing to progressive macrovascular and microvascular dysfunction. Macrovascular impairments, such as arterial stiffening and endothelial dysfunction, reduce nitric oxide (NO) bioavailability, leading to hypertension and impaired blood flow regulation. Microvascular dysfunction exacerbates cardiovascular decline by compromising capillary perfusion and tissue oxygenation, increasing susceptibility to ischemic events. Preserving vascular function is essential for maintaining cardiovascular health in aging populations.

Low-intensity aerobic exercise (LIAE) improves cardiovascular health and mobility, particularly in populations unable to perform high-intensity exercise. However, LIAE alone often fails to induce significant vascular adaptations, such as improved arterial compliance or endothelial function, highlighting the need for optimized interventions.

Blood Flow Restriction (BFR) enhances vascular adaptations during low-intensity exercise by inducing localized hypoxia, stimulating endothelial function and arterial remodeling. While BFR may transiently increase blood pressure and arterial stiffness, its vascular benefits resemble those of high-intensity exercise at lower workloads. However, research on BFR's acute vascular effects during aerobic exercise in older adults remains limited.

Current studies have focused on perceptual and hemodynamic responses to LIAE+BFR but lack direct assessments of macrovascular (e.g., flow-mediated slowing) and microvascular function. Older adults may exhibit distinct vascular responses, yet data are scarce. This study examines acute vascular responses to LIAE+BFR and high-intensity interval exercise (HIIE) in young and older adults.

Hypothesis:

1. BFR combined with LIAE will elicit greater acute microvascular and macrovascular responses in older adults than in younger adults. 2. These responses will be comparable to HIIE without BFR, suggesting BFR enhances LIAE's efficacy to high-intensity levels. 3. Any transient vascular dysfunction (e.g., increased arterial stiffness) will normalize within 30 minutes post-exercise, supporting safety in aging populations.