PERCEPTUAL AND HAEMODYNAMIC RESPONSES DURING MODERATE-SPEED WALKING ARE INCREASED BY BLOOD FLOW RESTRICTION IN OLDER ADULTS, BUT DO NOT EXCEED UNRESTRICTED FAST WALKING

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INTRODUCTION & AIMS Moderate-speed blood flow restriction (BFR) walking is an efficient exercise modality for older adults who cannot tolerate vigorous activity. However, limited data exist to guide the prescription of this exercise. This study examined the impact of different walking speeds and BFR cuff pressures on perceptual and haemodynamic responses, and compared these to unrestricted fast walking. METHODS Fifteen older adults (67-77 years) performed 10 sessions of 10-minute treadmill walking. In the first session, participants walked “as quickly as possible” to calculate mean fast walk speed. The following nine randomised sessions included moderate-speed walking with 50, 60 or 70% fast walk speed and 0%, 40 or 60% arterial occlusion pressure (AOP). Ratings of perceived discomfort (RPD) and exertion (RPE) were obtained, and blood pressure was assessed to calculate mean arterial pressure (MAP) and pulse pressure (PP). Perceptual scores were examined with Friedman ANOVA and Wilcoxon signed ranks tests, while MAP and PP were examined using linear mixed models (participants as random effects and speed, AOP or condition as fixed effects). RESULTS Higher RPD was observed using 60% AOP, followed by 40%, and 0% (p<0.001). RPE was higher for the fast walk (5.1±0.8 AU) than all other sessions (1.1±0.4 to 2.9±1.4 AU; p<0.001). MAP and PP were increased with higher AOP and walking speeds (p≤0.043). However, MAP (87.2±8.8 to 102.7±15.6 mmHg) and PP (66.3±14.4 to 80.3±21.7 mmHg) from moderate-speed BFR sessions did not significantly exceed measurements during the fast walk trial (MAP=100.1±13.6 mmHg, PP=89.0±22.5 mmHg). CONCLUSION Walking with BFR at 40% and 60% AOP increased limb discomfort and haemodynamic demands. Importantly, these responses did not exceed unrestricted fast walking, which caused the highest RPE. This study suggests a dose-response relationship of BFR cuff pressure with limb discomfort and haemodynamics, though these responses were not exacerbated more than unrestricted fast walking.

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