Daily energy expenditure and physical activity assessed by an activity diary in 374 randomly selected 15-year-old adolescents

Objectives: To assess the average daily levels of physical activity, energy expenditure and the time and energy spent at different activities in two cohorts of Swedish adolescents. Design: Total energy expenditure (TEE) and physical activity level (PAL = TEE/basal metabolic rate (BMR)) were estimated in 374 randomly selected healthy adolescents living in two different regions of Sweden on the basis of a seven-day activity diary (AD) and predicted BMR. A validation of the estimates from the AD with the doubly labelled water (DLW) method in a randomly selected subsample of 50 of these subjects is presented elsewhere. Setting: The Unit of Paediatric Physiology of the Department of Clinical Physiology, University Hospital, Uppsala and the Department of Paediatrics, Northern Alvsborg Hospital, Trollhattan, Sweden. Results: No significant differences in TEE and PAL were found between the adolescents of the two regions. High levels of TEE (14.2 and 10.9 MJ/d in boys and girls, respectively) and PAL (1.95 and 1.80) were observed. There was a close association between the PAL of the adolescents and their reported time spent sitting. Those with the lowest PAL values spent 3-6 h longer each day sitting compared to those with the highest PAL values. The results also indicate that everyday activities such as walking and bicycling have a crucial impact on the PAL values. Conclusions: In the 15 y old adolescents of the two studied regions of Sweden, high and concordant levels of energy expenditure and physical activity were found.