Ratings of Perceived Exertion During Walking: Predicting Major Mobility Disability and Effect of Structured Physical Activity in Mobility-Limited Older Adults

Abstract

Background This study evaluated the association between ratings of perceived exertion (RPE) of walking and major mobility disability (MMD), as well as their transitions in response to a physical activity (PA) compared to a health education (HE) program. Methods Older adults (n=1633) at risk for mobility impairment were randomized to structured PA or HE programs. During a 400m walk, participants rated exertion as “light” or “hard”. An MMD event was defined as the inability to walk 400m. MMD events and RPE values were assessed every 6-months for an average of 2.6 years. Results Participants rating their exertion as “hard” had a nearly 3-fold higher risk of MMD compared with those rating their exertion as “light” (HR: 2.61, 95%CI: 2.19-3.11). The association held after adjusting for disease conditions, depression, cognitive function and walking speed (HR: 2.24, 95%CI: 1.87-2.69). The PA group was 25% more likely to transition from “light” to “hard” RPE than the HE group (1.25, 1.05-1.49). Additionally, the PA group was 27% (0.73, 0.55 – 0.97) less likely to transition from a “hard” RPE to inability to walk 400m and was more likely to recover their ability to walk 400m by transitioning to a “hard” RPE (2.10, 1.39-3.17) than the HE group. Conclusions Older adults rating “hard” effort during a standardized walk test were at increased risk of subsequent MMD. A structured PA program enabled walking recovery, but was more likely to increase transition from "light" to "hard" effort, which may reflect greater capacity to perform the test.