Objective: PA habits reflect stable, consistent patterns in behaviours that are performed automatically in response to temporal or contextual cues. Mothers face multiple demands and complex schedules related to parenting. This study examined how subject-level mean, variability, and slopes in device-measured moderate-to-vigorous physical activity (MVPA) over three different timescales were associated with mothers' PA habits. Methods and Measures: Mothers (n = 125; Mage=41.4 years) completed six measurement periods across three years. Each measurement period consisted of seven days of accelerometry. MVPA minutes were processed across hours, days, and measurement periods. PA habits were assessed in the last measurement period. Results: Subject-level means of MVPA at all timescales were positively associated with stronger PA habits (βs = 0.42-0.48, ps<.01). Subject-level variability in day-level MVPA was positively associated with habits (β = 0.39, p=.01). Furthermore, mothers who engaged in higher mean day-level MVPA had a more positive association between subject-level variability in day-level MVPA and habit strength compared to mothers with lower mean day-level MVPA overall (β = 0.28, p=.04). Mothers who had steeper increases in MVPA across measurement periods (i.e. subject-level slope) reported stronger habits (β = 0.43; p = 0.03). Conclusion: Flexibly adjusting daily PA levels may be a necessary strategy to maintain habits in the face of parenting demands.
Keywords: Automaticity; exercise; exercise timing; moderate to vigorous intensity physical activity; temporal consistency.