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

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) who were at risk for mobility impairment were randomized to structured PA or HE programs. During a 400 m walk, participants rated exertion as "light" or "hard." An MMD event was defined as the inability to walk 400 m. 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 threefold higher risk of MMD compared with those rating their exertion as "light" (HR: 2.61, 95% CI: 2.19-3.11). The association was 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 (HR: 1.25, 95% CI: 1.05-1.49). Additionally, the PA group was 27% (HR: 0.73, 95% CI: 0.55 - 0.97) less likely to transition from a "hard" RPE to inability to walk 400 m and was more likely to recover their ability to walk 400 m by transitioning to a "hard" RPE (HR: 2.10, 95% CI: 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 the greater capacity to perform the test.