A recent European Journal of Preventive Cardiology study investigated whether sedentary time (ST), light-intensity physical activity (LPA), and moderate-to-vigorous-intensity physical activity (MVPA) during childhood and young adulthood influence cardiac structure and function.
Background
Since clinical events in the pediatric population are rare, identification of changes in cardiac structure and function in this population is crucial for early clinical diagnosis linked to cardiac damage. Higher left ventricular mass (LVM) is a significant marker of cardiovascular mortality among adults.
A recent study has indicated that elevated blood lipids content, high blood pressure, and increased arterial stiffness in adolescence are prominent indicators of premature cardiac damage in young adulthood.
Many longitudinal studies have highlighted the benefits of physical activity (PA) on cardiometabolic and vascular health in children and young adults. According to a recent guideline, individuals who are less than 18 years of age are recommended to perform an average of 60 minutes of moderate-to-vigorous-intensity PA (MVPA) daily. It must be noted that the majority of children fail to meet this daily recommendation.
A recent cross-sectional study linked ST with 30% higher cardiac mass, while a light-intensity PA (LPA) was associated with better cardiac function in adolescents. Since the majority of children and adolescents accumulate more time engaging in LPA than MVPA, it is imperative to understand whether cumulative increases in MVPA and LPA independently improve cardiac structure and function in youth.
Interestingly, a study highlighted that compared to MVPA, LPA is significantly more effective in lowering cholesterol levels, fat mass, vascular stiffness, and inflammation in the pediatric population.
Not many studies have evaluated the independent effect of modifiable lifestyle factors, such as ST and PA, on echocardiography-measured cardiac structure and function among the pediatric population. Furthermore, it is important to elucidate the sex-specific impact of ST and MVPA on cardiac functions in this population.
About the study
A previous study investigated the longitudinal associations of ST, LPA, and MVPA with cardiac structure and function in young adulthood. This is a secondary analysis from the Avon Longitudinal Study of Parents and Children (ALSPAC), UK birth cohort. A total of 1682 participants of 11 years of age from the ALSPAC birth cohort were selected. In the study period, each participant underwent at least one timepoint measure of ST, MVPA, and LPA at 11, 15, or 24 years. Furthermore, LVM indexed for height2.7 (LVMI2.7), left ventricular diastolic function E/A ratio (LVDF), relative wall thickness (RWT), and left ventricular filling pressure E/eʹ ratio (LVFP) measurements of the participants were collected.
ST, LPA, and MVPA were measured using an accelerometer that was worn by the participants around their waist. This device detected and recorded acceleration and deceleration in a vertical plane, a function of movement frequency and intensity. This device was worn during waking hours of three days a week, i.e., two weekdays and one weekend day. The cardiac condition was assessed based on LVDF and LVFP measurements. The height and body mass index (BMI) of participants were recorded.
Study findings
The current study indicated that accelerometer-measured cumulative ST, MVPA, and LPA during participants’ childhood through young adulthood were independently and differently associated with the changes in cardiac structure and function during growth.
Out of 1682 participants, 62.7% were female. As per the criteria, the ST, LPA, and MVPA of these participants were measured at least one time during the ages 11–24 years. It was observed that males had around 4 g/m2.7 of LVM more than females at both baseline and follow-up. However, RWT, LVDF, and LVFP measures were similar in both sexes. From 11 to 24 years, males accumulated more MVPA minutes than females, while the latter exhibited higher ST.
A cumulative increase in ST from childhood through young adulthood was connected with elevated cardiac mass. However, cumulative LPA from childhood was associated with reduced cardiac mass. Surprisingly, cumulative MVPA was linked with elevated cardiac mass and decreased cardiac function. Furthermore, persistent MVPA of more than 60 minutes per day caused a decrease in cardiac function in young adulthood. However, persistent MVPA of 40 minutes to less than 60 minutes per day was associated with a decrease in cardiac mass.
This study observed that the increase in ST-induced LVMI was eight times greater than the MVPA-included LVMI increase during growth, i.e., from adolescence to young adulthood. These findings underscore ST as a modifiable factor that leads to cardiac pathologies.
Conclusion
The current study highlighted how ST, MVPA, and LPA can be independently modified during childhood through young adulthood for improved cardiac function and structure. For instance, increasing LPA and reducing ST can alleviate or reverse the progressively worsening changes in cardiac structure and function.
The current study highlights the benefits of LPA in the pediatric population, particularly those diagnosed with obesity and hypertension. These observations can be considered when developing health guidelines.