Duration of moderate to vigorous daily activity is negatively associated with slow walking speed independently from step counts in elderly women aged 75 years or over: A cross-sectional study.

OBJECTIVES: This study aimed 1) to examine whether objectively measured duration of moderate to vigorous physical activity (MVPA) was associated with slow walking speed, independent from step counts, in elderly women aged 75 or over (old-old) and 2) to determine a possible cut-off value for duration of MVPA related to slow walking speed.

METHODS: Participants were 350 community-dwelling old-old women. Slow walking speed was defined as usual walking speed <1.0m/s. Duration of MVPA (activity at an intensity >3 metabolic equivalents) and number of step counts were measured using a uniaxial accelerometer over 1 wk. Body mass index, grip strength, back and leg pain, cognitive function, executive function, and presence of depression were also assessed. Participants with missing data were excluded from the main analysis.

RESULTS: The mean age of the participants was 79.9±3.6 y. The prevalence of slow walking speed was 14.9%. Multiple logistic regression analysis showed that the duration of MVPA was significantly and inversely associated with slow walking speed, independent from step counts and other confounding factors (adjusted odds ratio=0.94 per 1min/d increment, 95% confidence interval=0.73-0.99; p=0.031). This relationship was also observed in sensitivity analysis that included all participants. A MVPA cut-off value of 8.7min/d was determined using the receiver operating characteristic analysis.

CONCLUSION: The findings from the present study suggest that promoting MVPA may be helpful to prevent slow walking speed. The validity of MVPA for predicting slow walking speed needs to be confirmed in future prospective studies.