Active-day Exercise Duration and Cardiovascular Health Metrics: Novel Insights from NHANES 2007 - 2020

Background Current physical activity (PA) guidelines emphasize weekly volume, but how activity is distributed across active days may also influence cardiovascular health (CVH). We examined whether these weekly accumulation patterns are associated with CVH. Methods We conducted a cross-sectional analysis of adults aged 20-64 years without established cardiovascular disease (CVD) in the National Health and Nutrition Examination Survey (2007- March 2020). PA was self-reported and categorized as inactive (< 30 min/week), low-volume (30-89 min/week), intermediate-volume (90-149 min/week), or guideline-adherent (150 min/week). Within low- and intermediate-volume groups, participants were further classified as distributed (<30 or < 45 minutes on active days) or concentrated (30 or 45 minutes on active days). CVH was assessed using the American Heart Association's Life's Essential 8 (LE8). Associations were examined with LOESS smoothing and propensity score matching. Results Among 9,851 participants, 48.7% were inactive and only 33.2% met guideline PA levels. In the low-volume group, those with concentrated patterns (30 minutes on active days) had significantly better blood pressure scores compared with distributed patterns (<30 minutes; p=0.045). In the intermediate-volume group, the concentrated patterns (45 minutes on active days) were associated with more favorable glycemic (p<0.001) and lipid profiles (p=0.013), independent of total weekly volume. Dose-response analyses identified 30-45 minutes on active days as the optimal range for cardiometabolic benefits. Conclusion Weekly accumulation patterns independently influenced CVH among adults below guideline PA levels. Concentrating 30-45 minutes on active days was associated with better blood pressure, glucose, and lipid profiles without increasing weekly volume. These findings highlight active-day duration as a novel, modifiable, and time-efficient behavioral target for cardiovascular prevention.