Effects of Blood Flow Restriction Aerobic Exercise on Inflammation, Hypoxia, Exercise Capacity, and Lung Function in COPD

Condition(s) studied

Investigational drug(s) / intervention(s)

Blood Flow Restriction Aerobic Exercise Training: Blood Flow Restriction Aerobic Exercise Training Participants will undergo aerobic exercise performed with blood flow restriction (BFR) applied to both thighs using pneumatic cuffs positioned at the proximal portion of the lower limbs. Cuff pressure will be individualized for each participant based on limb occlusion pressure (LOP), determined by Doppler assessment. During training, cuffs will be inflated to 40-50% of the participant's LOP and will remain inflated throughout the aerobic exercise phase. Sessions will include warm-up, continuous low-intensity cycling, and cool-down, supervised by a physiotherapist. The purpose of this intervention is to induce physiological adaptations associated with BFR, such as increased metabolic stress and muscular activation, while using low mechanical load.

Conventional Aerobic Exercise Training: Participants in this group will perform aerobic exercise on a cycle ergometer without blood flow restriction (BFR) as part of standard pulmonary rehabilitation. The aerobic exercise protocol will be performed at 60-80% of the participant's target heart rate (THR), calculated using the Karvonen formula: THR = \[(HRmax - HRrest) × % intensity\] + HRrest. Training will be performed twice per week for a total of 8 weeks and will include 3 minutes of warm-up, 15 minutes of target-intensity aerobic cycling, and 3 minutes of cool-down (total duration: 21 minutes). Pedal resistance and cadence will be adjusted according to the Borg Rating of Perceived Exertion (RPE), with the target RPE maintained between 3 and 4. Exercise intensity (watt level) will be progressed weekly by approximately 5-10%, aligned with tolerance and RPE scores (Patterson et al., 2019). No BFR will be applied at any stage of the intervention.

Study summary

Purpose:

This study aims to compare the effects of the classical pulmonary rehabilitation (PR) program and blood flow restriction (BFR) applied during low-intensity aerobic exercise within PR on systemic inflammation, hypoxemia, exercise capacity, pulmonary function, respiratory muscle strength, and quality-of-life parameters in individuals with COPD.

Methods:

This randomized controlled study will include 34 individuals with COPD, allocated into a BFR aerobic group and a control group. Both groups will receive core PR components, including diaphragmatic breathing, pursed-lip breathing, respiratory muscle training, and peripheral muscle strengthening. The BFR group will perform low-intensity aerobic exercise with blood flow restriction, while the control group will perform moderate-intensity aerobic exercise without BFR in accordance with standard PR protocols. All sessions will be supervised by a physiotherapist, twice per week, for eight weeks. Systemic inflammation markers, arterial blood gases, pulmonary function, exercise capacity, quality of life, and symptom scores will be assessed before PR, after the 8th session, and at the end of the program. Data will be analyzed using SPSS 26.0.

Expected Contribution:

This study aims to provide evidence-based insights into the physiological and clinical effects of low-intensity BFR aerobic exercise within PR and to determine its potential advantages compared with classical PR. Additionally, it seeks to clarify whether low-intensity BFR aerobic exercise may serve as a better-tolerated alternative for COPD patients who experience exercise intolerance during moderate-intensity aerobic training.

Eligibility

Primary outcome measure(s)

• Change in Exercise Capacity — Baseline and 8 weeks after intervention
  Exercise capacity will be evaluated using the 6-Minute Walk Test (6MWT), conducted according to ATS guidelines in a 30-meter corridor. The total distance walked in 6 minutes (6MWD) will be recorded as the primary indicator of functional exercise capacity. The outcome measure will assess the change in 6MWT distance from baseline to 8 weeks following the intervention in COPD patients undergoing pulmonary rehabilitation with or without blood flow restriction (BFR). An increase in 6MWD reflects improvement in exercise capacity.

Trial sites (1)

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