Research Database

Isolating out-of-bed wear from non-wear and in-bed wear periods in young adults hip-worn accelerometer data (continuous wear protocol)

  • Presented on 2015

Background: The published literature shows no automated method valid for isolating adults out-of-bed wear in continuously worn (24h/day) accelerometer data. We developed an automated algorithm (AA) for continuous hip-worn protocol Actigraph (GT3X+) data that separates out-of-bed wear from in-bed wear and non-wear periods. Methods: In 95 participants of the ...



Separating Bedtime Rest from Activity Using Waist or Wrist-Worn Accelerometers in Youth

  • Published on April 11, 2014

Abstract: Recent interest in sedentary behavior and technological advances expanded use of watch-size accelerometers for continuous monitoring of physical activity (PA) over extended periods (e.g., 24 h/day for 1 week) in studies conducted in natural living environment. This approach necessitates the development of new methods separating bedtime rest and activity ...


Assessing sleep using hip and wrist actigraphy

  • Published on Jan. 19, 2015

Abstract: Wrist actigraphy is commonly used to measure sleep, and hip actigraphy is commonly used to measure activity. It is unclear whether hip-based actigraphy can be used to measure sleep. This study assessed the validity of wrist actigraphy and hip actigraphy compared to polysomnography (PSG) for the measurement of sleep. 108 ...


The home environment and childhood obesity in low-income households: indirect effects via sleep duration and screen time

  • Published on Nov. 9, 2014

Background: Childhood obesity disproportionately affects children from low-income households. With the aim of informing interventions, this study examined pathways through which the physical and social home environment may promote childhood overweight/obesity in low-income households. Methods: Data on health behaviors and the home environment were collected at home visits in ...


Low Physical Activity Level and Short Sleep Duration Are Associated with an Increased Cardio-Metabolic Risk Profile: A Longitudinal Study in 8-11 Year Old Danish Children

  • Published on Aug. 7, 2014

Background: As cardio-metabolic risk tracks from childhood to adulthood, a better understanding of the relationship between movement behaviors (physical activity, sedentary behavior and sleep) and cardio-metabolic risk in childhood may aid in preventing metabolic syndrome (MetS) in adulthood. Objective: To examine independent and combined cross-sectional and longitudinal associations between movement ...


Identifying Children's Nocturnal Sleep Using 24-h Waist Accelerometry

  • Published on Sept. 8, 2014

Purpose: The purposes of this study were (1) to add layers and features to a previously published fully automated algorithm designed to identify children's nocturnal sleep and to exclude episodes of nighttime non-wear/wakefulness and potentially misclassified day time sleep episodes, and (2) to validate this refined sleep algorithm (RSA) against sleep ...


Interrelationships among sedentary time, sleep duration, and the metabolic syndrome in adults

  • Published on June 30, 2014

Background: The study objectives were to examine whether: 1) sedentary time is associated with sleep duration, 2) sedentary time predicts the metabolic syndrome (MetS) independent of sleep duration and vice versa, and 3) sedentary time and sleep duration have an interactive effect on the MetS. Methods: This cross-sectional study is based on the 2003–2006 ...


Sleep Variability and Cardiac Autonomic Modulation in Adolescents: The Penn State Child Cohort

  • Presented on June 2, 2014

Introduction: The association between habitual sleep patterns and cardiac autonomic modulation (CAM) in adolescents is not fully understood. We investigated such association in the population-based Penn State Child Cohort (PSCC) follow-up examination. Methods: An actigraph (GT3X) and a sleep diary were used in 421 adolescents for 7 consecutive nights to calculate ...


Sleep Variability and Nutrition Intake in Adolescents: The Penn State Child Cohort

  • Presented on June 2, 2014

Introduction: The association between habitual sleep patterns and nutrition intake is not fully understood, especially in adolescents. We investigated the association between habitual sleep duration and its variability with nutrition intake in population-based adolescents of the Penn State Child Cohort (PSCC) follow-up examination. Methods: An actigraph (GT3X) and a ...