Abstract Body: Introduction: Few studies have examined the longitudinal associations of accelerometry-based measures of sedentary and physical activity behaviors with subclinical heart failure (HF) in midlife. This is a key gap given an improved understanding of modifiable factors associated with HF risk may better inform prevention strategies.

Hypothesis: More time in light intensity physical activity and/or moderate or vigorous intensity physical activity and less sedentary time will be related to lower levels of clinical HF biomarkers (NT-proBNP and hscTnT) across midlife_.

Methods: Data are from 2,844 CARDIA participants [57.9% women, 45.0% Black persons, aged 45.3 ± 3.6 years at the Year 20 exam (baseline for this analysis; 2005-06)] with at least one available timepoint of valid accelerometer (ActiGraph) wear (≥4 of 7 days with ≥10 hours per day of wear) and HF biomarkers at baseline and 10- and/or 15-years later. Linear mixed effects models, adjusted simultaneously for time spent sedentary and in light- or moderate or vigorous- intensity physical activity (partition model), sex, race, age, center, education, difficulty paying for basics, alcohol and tobacco use, obesity, diabetes, hypertension and hypercholesterolemia, were used to estimate the associations.

Results: From baseline to 15-year follow-up, mean (± SD) time spent sedentary increased (488.1 ± 104.3 to 537.5 ± 112.0 min/d) and time spent in light intensity physical activity and moderate or vigorous intensity physical activity decreased (360.1 ± 86.7 to 312.1 ± 87.2 min/d and 37.3 ± 51.7 to 22.1 ± 22.4 min/d, respectively). Over this same period, mean (± SD) HF biomarkers increased (NT-proBNP: 61.6 ± 91.8 to 145.8 ± 1,111.9 pg/mL and hscTnT: 7.8 ± 4.7 to 11.0 ± 28.7 ng/L)). After adjustment, every 5-minute higher moderate or vigorous intensity physical activity was associated with lower NT-proBNP and hscTnT over 15 years (Table).

Conclusions: Findings highlight the importance of moderate or vigorous intensity physical activity during the midlife transition for subclinical HF prevention, demonstrating this association before the onset of overt signs or symptoms.