Within- and between-individual variability in estimated energy expenditure and habitual physical activity among young adults

Objective: To examine the within- and between-individual variability in the estimated total energy expenditure (TEE) and habitual physical activity (PA) in free-living young adults. We were specifically interested in the day-to-day variation. Design: Cross-sectional. Setting: University. Subjects: A total of 277 (125 males, 152 females) participants aged 18-24 years. Interventions: None. Main outcome measures: Subjects recorded their daily PA with the Bouchard 3-day diary. Descriptive statistics for TEE, moderate-to-vigorous physical activity (MVPA), inactivity (IA), and activity energy expenditure (AEE) were calculated and presented as a frequency distribution. Within- and between-individual variability were tested by RMANOVA and also presented as the coefficient of variation (CV). Results: Mean values for TEE, MVPA, AEE, and IA were comparable between males and females; however, considerable between-individual variability existed. Only MVPA showed a significant difference between sexes (P