Interactions of sedentary behavior, physical activity, and sleep in early childhood

children jumping in playground

Although physical activity, sedentary behavior, and sleep (i.e., 24-hr behaviors) have been associated with cognitive and brain outcomes in older children and adults, studies in early childhood are limited and typically examine these behaviors separately. Early childhood serves as an important time for brain and cognitive development and is a time when healthy habits (i.e., low sedentary time, high physical activity, and sufficient sleep) are formed.

Christine St. Laurent, post-doctoral researcher in the Somneuro Lab directed by Rebecca Spencer, has been awarded an NIH Ruth L. Kirschstein National Research Service Award fellowship to pursue research examining the relations between early childhood 24-hr behaviors, cognition, and brain structures associated with learning and memory.

The specific aims of the project will be to determine if 24-hr behaviors are associated with 1) cognitive performance and 2) hippocampal volume in early childhood. Data from two ongoing studies examining the benefits of napping on memory in early childhood will be used: a clinical trial with one measurement period and a longitudinal clinical trial with three measurement periods over one year.

In order to find possible associations with learning and memory, analyses from various subgroups of participants of the two studies will be conducted. Measurements will include time spent in each of the 24-hr behaviors from 16-days of actigraphy (i.e., accelerometry via a wrist monitor), cognitive performance from multiple assessments, and hippocampal subfield volumes from magnetic resonance imaging. This investigation could reveal that 24-hour behaviors have synergistic effects on cognitive outcomes (e.g., getting more sleep and increasing physical activity may improve learning more than just changing one behavior alone).

The findings from this research will have public health significance in that they will identify potential windows of opportunity to intervene on health behaviors, learning, and cognitive function at a critical developmental period of the lifespan. Project results can inform future intervention studies, family practices, early childhood education policies, and comprehensive guidelines for a 24-hr cycle. This fellowship will provide St. Laurent with cross-disciplinary mentorship and valuable training in developmental science, sleep, neurocognitive measurement, statistical analyses, and scientific writing.

St. Laurent remarks, “I am looking forward to having extended protected time to continue my postdoc training under Dr. Rebecca Spencer, which for me has been an incredible experience so far. The opportunity to learn from and work with her and others in the Department of Psychological and Brain Sciences is complimentary, yet distinct from my predoctoral education and professional experiences and I am thrilled for this opportunity. I am also excited to collaborate and learn from my co-sponsor, Dr. Tracy Riggins, and her team at the University of Maryland.”