Relationships of Objectively Measured PA and Sleep with BMI and Academic Outcomes in 8-year-old Children

Sunday, 17 November 2013: 11:00 AM

Susan Harrington, PhD, RN
Kirkhoff College of Nursing, Grand Valley State University, Grand Rapids, MI

Learning Objective 1: Explain the relationships between physical activity dimensions and sleep characteristics.

Learning Objective 2: Describe the consequences of physical inactivity and sleep deprivation on academic achievement and behavior.

Secular trends reveal less physical activity (PA) and sleep duration in school aged children.  Current guidelines for sleep and PA are the result of data collected in the form of self-reports.  Quantification of PA dimensions and sleep characteristics are essential for establishing and verifying health parameters.

The Bronfenbrenner Bioecological Model guided this study through use of multilevel comparisons and modifications between a child and his surroundings.  This frame encouraged the conceptualization of reciprocal forces.  The rapid rise of overweight/obesity in children can be explained primarily through the synergistic combination of environmental factors.

The purpose of this study was to examine the relationships between PA, sleep, academic achievement, and academic behavior with weight status.  This cross-sectional correlational descriptive study measured PA and sleep duration for 24 hours/day for 7 consecutive days with a triaxial accelerometer.  Data were successfully gathered on 55 low socioeconomic African American third graders (8-yr-olds).  Body mass index (BMI) was calculated using CDC guidelines.  Standardized scores, teacher grades, and attendance records were acquiesced from the three participating charter schools. 

Results revealed that 55% of this sample was classified as either overweight or obese.  Light intensity activity accounted for 86% of daytime PA.  Vigorous activity levels accounted for less than 1%.  Moderate-vigorous activity bouts were inversely correlated with standardized reading scores.  Students with failing reading scores had significantly more light activity and fewer registered steps/day.  Children with the highest absenteeism demonstrated the highest percentage of light intensity activity.  This sample proved to be sleep deprived, averaging 8 hours of sleep/night.  Obese children slept significantly less than the normal weight children, supporting prior research.  A relatively small reduction in sleep time can impact health outcomes. 

Future interventional studies associated with the manipulation of energy expenditure as it relates to sleep, weight status and academic progress are pending.