Accelerometer-based sedentary time and physical activity from childhood through young adulthood with progressive cardiac changes: a 13-year longitudinal study.

ST contributed +40% to the 7-year increase in cardiac mass, MVPA increased cardiac mass by +5%, but LPA reduced cardiac mass by -49%. Increased ST may have long-term pathologic effects on cardiac structure and function during growth from childhood through young adulthood; however, engaging in LPA may enhance cardiac health in the young population.