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

Summary

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.

Conditions

• Ageing
• Blood Flow Restriction (BFR) Training Effects

Interventions

OTHER

Low Intensity Aerobic Exercise with Blood Flow Restriction (LIAE+BFR)

In the LIAE+BFR condition, participants will walk on a treadmill for 20 minutes at 30-40% of heart rate reserve (HRR), with a pneumatic cuff inflated to 1.3 times the individual's ankle systolic blood pressure, using a 5cm wide x 75cm long commercial cuff around each upper thigh. Treadmill speed will be adjusted dynamically to maintain target intensities, while the incline remains at 1%. Heart Rate, the Modified Borg Rate of Perceived Exertion scale, and the Rating of perceived discomfort will be continuously monitored throughout both exercise sessions to ensure adherence to the prescribed intensity levels.

OTHER

High Intensity Interval Exercise (HIIE)

In the HIIE condition, participants will perform a 20 minutes treadmill-based HIAE, alternating between 60-seconds high-intensity intervals at 60-89% HRR and 60-second active recovery intervals at 40-50% HRR. Treadmill speed will be adjusted dynamically to maintain target intensities, while the incline remains at 1%. Heart Rate, the Modified Borg Rate of Perceived Exertion scale, and the Rating of perceived discomfort will be continuously monitored throughout both exercise sessions to ensure adherence to the prescribed intensity levels.

Sponsors & Collaborators

• Egas Moniz - Cooperativa de Ensino Superior, CRL

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

SUPPORTIVE_CARE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-10-06

Primary Completion

2026-05-29

Completion

2026-07-31

Countries

• Portugal

Study Locations