Associations of exercise snack–related step metrics with peripheral artery disease in older women: a cross-sectional study

Abstract

Peripheral artery disease is a common vascular condition associated with impaired physical function and reduced quality of life in older adults. Although step volume and stepping intensity have been linked to cardiovascular health, the associations of intensity-specific step counts, cadence, and short-bout step accumulation with peripheral artery disease remain unclear. The concept of “exercise snacks,” characterized by brief, intermittent bouts of moderate-to-vigorous physical activity, provides a useful framework for examining such activity patterns in free-living settings. This study examined the associations of objectively measured step counts, cadence, and bout-specific step accumulation with peripheral artery disease among community-dwelling older women. This cross-sectional study included 1053 community-dwelling women aged 60–70 years from the Physical Activity and Health in Older Women Study. Step-based metrics were assessed using a waist-worn ActiGraph accelerometer over seven consecutive days. Steps were categorized as light-intensity physical activity or moderate-to-vigorous physical activity. Step cadence and bout-specific step accumulation (≥ 3, ≥ 5, and ≥ 10 min) were also derived. Peripheral artery disease was defined as an ankle–brachial index ≤ 0.90. Multivariable logistic regression and restricted cubic spline analyses were performed to evaluate associations between step-based metrics and peripheral artery disease. Sensitivity analyses were conducted using the lower ankle–brachial index value from either leg as a continuous outcome and supplementary parsimonious regression models to reduce the potential influence of model overfitting. After full adjustment, more steps accumulated during moderate-to-vigorous physical activity (odds ratio = 0.696, 95% confidence interval: 0.531–0.912, P  = 0.009) and higher cadence during moderate-to-vigorous physical activity (odds ratio = 0.967, 95% confidence interval: 0.952–0.983, P  < 0.001) were associated with lower odds of peripheral artery disease, whereas steps and cadence during light-intensity physical activity showed no significant associations. Moderate-to-vigorous physical activity steps accumulated in ≥ 3- and ≥ 5-minute bouts were significantly associated with lower odds of peripheral artery disease, whereas findings for ≥ 10-minute bouts were less robust in sensitivity analyses using ankle–brachial index as a continuous outcome. Restricted cubic spline analyses showed a non-linear inverse association between moderate-to-vigorous physical activity steps and peripheral artery disease, with an exploratory slope change at approximately 2,134 steps per day, and a linear inverse association for moderate-to-vigorous physical activity cadence using 71 steps per minute as the reference. Higher moderate-to-vigorous physical activity–related step counts, faster cadence, and greater accumulation of moderate-to-vigorous physical activity in short bouts were associated with lower odds of peripheral artery disease among older women, whereas light-intensity physical activity–related metrics were not. These findings highlight intensity-related and short-bout walking patterns that warrant further investigation but do not support specific behavioral recommendations because of the cross-sectional study design.