Background-—Isotemporal substitution examines the effect on health outcomes of replacing sedentary time with light-intensity physical activity or moderate-to-vigorous intensity physical activity; however, existing studies are limited by cross-sectional study designs. Methods and Results-—Participants were 1922 adults from the CARDIA (Coronary Artery Risk Development in Young Adults) study. Linear regression examined the associations of sedentary, light-intensity physical activity, and moderate-to-vigorous intensity physical activity at year 20 (2005–2006) with waist circumference, blood pressure, glucose, insulin, triglycerides, high-density lipoprotein cholesterol, and a composite risk score at year 30 (2015–2016). Models then examined change in activity with change in cardiometabolic risk over the same 10-year period. Replacing 30 min/day of sedentary time with 30 min/day of light-intensity physical activity at year 20 was associated with a lower composite risk score ( 0.01 SD [95% CI, 0.02, 0.00]) at year 30, characterized by lower waist circumference (0.15 cm [95% CI, 0.27, 0.02]), insulin (0.20 lU/mL [95% CI, 0.35, 0.04]), and higher high-density lipoprotein cholesterol (0.20 mg/dL [95% CI, 0.00, 0.40]; all P<0.05). An increase of 30 min/day in MVPA from year 20 to year 30, when replacing an equivalent increase in sedentary time, was associated with a decrease in the composite risk score ( 0.08 [95% CI, 0.13, 0.04]) over the same 10 years, characterized by a decrease in waist circumference (1.52 cm [95% CI, 2.21, 0.84]), insulin ( 1.13 lU/mL [95% CI, 1.95, 0.31]), triglycerides ( 6.92 mg/dL [95% CI, 11.69, 2.15]), and an increase in high-density lipoprotein cholesterol (1.59 mg/dL [95% CI, 0.45, 2.73]; all P<0.05). Conclusions-—Replacement of sedentary time with light-intensity physical activity or moderate-to-vigorous intensity physical activity is associated with improved cardiometabolic health 10 years later.
Bibliographical noteFunding Information:
The Coronary Artery Risk Development in Young Adults Study (CARDIA) is supported by contracts HHSN268201300025C, HHSN268201300026C, HHSN268201300027C, HHSN2682 01300028C, HHSN268201300029C, and HHSN26820090 0041C from the National Heart, Lung, and Blood Institute (NHLBI), the Intramural Research Program of the National Institute on Aging (NIA), and an intra-agency agreement between the NIA and NHLBI (AG0005). Accelerometer data collection was supported by grants R01 HL078972 and R56 HL125423 from the NHLBI. Whitaker was supported by T32 HL007779 from the NHLBI.
- Cardiometabolic risk
- Isotemporal substitution
- Physical activity
- Sedentary time