Differences in prolonged walking intensity and duration between older people reporting difficulty, modifications or no difficulty in walking.

Older people report modifying their walking by slowing down speed or using walking aids to accommodate increased exertion and the decline in physical capacity. Self-reported walking modifications and difficulties are associated with daily walking accumulation; however, the relationship between self-reported walking ability and prolonged walking intensity and duration is not well understood. This cross-sectional study compared walking speed, duration, and changes in intensity during prolonged walking bout between older people self-reporting walking difficulty, modifications, or no difficulty in walking. Participants (n = 104, 51 % women, age 78-90 years) performed a prolonged walking test at a constant speed based on Borg's rating of perceived exertion (RPE 13), walking at a constant speed until reaching RPE 16 or the maximum test duration (30 min). Wearable sensors recorded heart rate (HR), accelerometry, and cadence during the test. Walking speed was slower for older people reporting walking difficulty (1.17 ± 0.23) than for those reporting modifications (1.34 ± 0.19, p = 0.010) or no difficulty (1.42 ± 0.19, p < 0.001), which was similarly observed in accelerometry. No differences were found in walking duration (p = 0.205). Changes in RPE, HR, acceleration, and cadence did not differ between the walking ability categories. In conclusion, older people with self-reported walking difficulties were able to sustain the same perceived exertion level, but at a lower speed and acceleration, during prolonged walking as those without difficulties, for the same duration. These results highlight the importance of developing metrics for wearable sensors that reflect perceived exertion and its changes during prolonged activity bouts.