AHA Scientific Sessions 2026 Abstract · Nov 2, 2026
24-Hour Behavior Time Reallocation and Cardiometabolic Risk by Neighborhood Disorder Among Midlife Women: An Isotemporal Substitution Analysis
By Lee S, Joyce C, Park C et al.
Introduction: Sleep, physical activity, and sedentary behavior are interdependent 24-hour behaviors that influence cardiometabolic health. Neighborhood environments may shape these behaviors, but little is known about whether cardiometabolic benefits associated with 24-hour behavior time reallocation differ by neighborhood context. This study examined associations between 24-hour behavior time reallocation and cardiometabolic risk indicators among midlife women and whether neighborhood disorder modified these associations. Hypothesis: Reallocating time among 24-hour behaviors would be associated with more favorable cardiometabolic risk indicators, and these associations would differ by neighborhood disorder. Methods: We analyzed cross-sectional All of Us Research Program data from women ages 40-65 years with Fitbit-derived behaviors, neighborhood disorder scores, and at least one cardiometabolic risk indicator. Participants had ≥7 valid consecutive Fitbit wear days. Behaviors included sleep, sedentary behavior, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). Outcomes were body mass index (BMI), systolic blood pressure (SBP), and high-density lipoprotein cholesterol (HDL-C). Neighborhood disorder was assessed using the Neighborhood Disorder Scale and categorized using a median split of the analytic sample. Isotemporal substitution models estimated associations of 30-minute/day reallocations, adjusting for demographic characteristics, smoking, menopausal status, and Fitbit wear days. Interactions tested modification by neighborhood disorder. Results: Among 2,832 midlife women (52.7 ± 7.1 years), sleep averaged 389.6 ± 66.3 minutes/day, sedentary behavior exceeded 11 hours/day (699.3 ± 116.6 minutes/day), and MVPA averaged 27.3 ± 26.6 minutes/day. In the overall sample, reallocating 30 minutes/day of sedentary time to MVPA was associated with lower BMI (β = –0.76 kg/m ² , p < .001), lower SBP (β = –1.33 mmHg, p = .007), and higher HDL-C (β = 4.21 mg/dL, p < .001). Subgroup patterns varied by neighborhood disorder: reallocating sedentary time to LPA was associated with lower SBP in the high-disorder group (β = –0.72 mmHg, p = .007), whereas reallocating sedentary time to MVPA was associated with lower SBP (β = –2.00 mmHg, p = .003) and BMI (β = –1.03 kg/m ² , p < .001) in the low-disorder group. Neighborhood disorder modified the association between reallocating sedentary time to LPA and SBP (interaction p = .002). Conclusions: Reallocating sedentary time to MVPA was associated with the most consistently favorable cardiometabolic profile among midlife women. However, associations varied by neighborhood disorder, suggesting that feasible behavioral targets may differ across environmental contexts. These findings support context-appropriate approaches that promote both MVPA and achievable increases in LPA.