Acute physiological responses to low-intensity blood flow restriction cycling

Area of Science:

• Exercise Physiology
• Cardiovascular Adaptation
• Sports Science

Background:

• Blood flow restriction (BFR) is a technique used during exercise.
• Its potential to enhance aerobic and anaerobic adaptations through interval cycling is recognized.
• However, the acute physiological responses to BFR interval cycling require further investigation.

Purpose of the Study:

• To investigate the acute physiological responses to low-intensity (LI) interval cycling with and without blood flow restriction (BFR).
• To compare these responses with high-intensity (HI) interval cycling.

Main Methods:

• Eighteen males participated in randomized, counterbalanced sessions: LI, LI with BFR (LI_BFR), and HI interval cycling.
• Sessions involved three 2-minute intervals at 40% (LI, LI_BFR) or 85% (HI) peak power output, with 2-minute recovery.
• Physiological measures included heart rate (HR), cardiac output (CO), oxygen consumption (V˙O₂), blood pressure (BP), rating of perceived exertion (RPE), and blood lactate.

Main Results:

• High-intensity (HI) interval cycling elicited the greatest responses in BP, HR, CO, V˙O₂, lactate, and RPE.
• LI_BFR resulted in greater BP, HR, and CO during intervals compared to LI.
• V˙O₂ during recovery and post-exercise lactate were higher in LI_BFR than LI.
• Mean arterial pressure during the third interval was significantly higher in LI_BFR than HI.

Conclusions:

• Low-intensity interval cycling with blood flow restriction (LI_BFR) enhances cardiovascular and metabolic stress relative to LI cycling alone.
• LI_BFR may serve as a viable alternative training modality for individuals unable to perform high-intensity exercise.
• The elevated mean arterial pressure during LI_BFR suggests a significant myocardial workload, necessitating caution in individuals with compromised vascular health.