Snacktivity in older women: accelerometer-derived step counts, cadence, and bout patterns associated with adiposity.

backgroundSnacktivity—brief, high-frequency bouts of moderate-to-vigorous physical activity (MVPA) integrated into daily routines—may interrupt prolonged sitting and help accumulate total activity. Step count is a practical proxy for this pattern, yet the cadence thresholds that map short-bout stepping to MVPA and the relevance of bout–cadence patterns to adiposity remain unclear. This study aimed to examine the associations between accelerometer-derived step metrics and adiposity and to identify pragmatic step-based thresholds in older women.

methodsWe conducted a cross-sectional study of 1,109 community-dwelling older women in Yantai, Shandong Province, China, with a mean age of 64.93 years (SD = 2.82). Step-based metrics (daily steps, MVPA and light-intensity physical activity (LPA) steps, cadence, and bout patterns) were derived from a waist-worn triaxial accelerometer. adiposity was defined using body-fat-ratio (BFR) categories assessed by multi-frequency bioelectrical impedance analysis. Multiple linear regression estimated associations with progressive adjustment for sociodemographic, lifestyle, and health-related covariates, with additional adjustment for total sedentary time. Sensitivity analyses replaced BFR with BMI and examined visceral fat mass (VFM) using linear regression. Receiver operating characteristic (ROC) analyses identified pragmatic step and cadence cut-points.

resultsMVPA step counts and cadence were consistently and inversely associated with adiposity (p < 0.001), whereas LPA-related metrics were largely non-significant. ROC analyses indicated modest discrimination, with higher performance for MVPA-based metrics than for LPA-based metrics. The optimal Youden index–derived thresholds were 1,846 MVPA steps/day (AUC = 0.625), 94.3 steps/min for MVPA cadence (AUC = 0.626), and 6,287 total steps/day (AUC = 0.600), while LPA steps showed near chance-level discrimination (AUC = 0.515). Accumulating ≥ 1,846 MVPA steps/day was consistently associated with lower adiposity-related outcomes across bout definitions (≥ 3, ≥ 5, ≥10 min), supporting a short-bout “snacktivity” pattern.

conclusionsAmong older women, MVPA-oriented step metrics—particularly ~ 1,846 MVPA steps/day and ~ 94.3 steps/min cadence—showed inverse associations with adiposity and outperformed LPA metrics. These thresholds may serve as pragmatic, low-barrier activity targets, but causal relationships require confirmation in longitudinal and experimental studies.