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, e nergy expenditure and the time and energy spent at different activitie s in two cohorts of Swedish adolescents. Design: Total energy expendit ure (TEE) and physical activity level (PAL = TEE/basal metabolic rate (BMR)) were estimated in 374 randomly selected healthy adolescents liv ing in two different regions of Sweden on the basis of a seven-day act ivity diary (AD) and predicted BMR. A validation of the estimates from the AD with the doubly labelled water (DLW) method in a randomly sele cted subsample of 50 of these subjects is presented elsewhere. Setting : The Unit of Paediatric Physiology of the Department of Clinical Phys iology, University Hospital, Uppsala and the Department of Paediatrics , Northern Alvsborg Hospital, Trollhattan, Sweden. Results: No signifi cant 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 gi rls, respectively) and PAL (1.95 and 1.80) were observed. There was a close association between the PAL of the adolescents and their reporte d time spent sitting. Those with the lowest PAL values spent 3-6 h lon ger each day sitting compared to those with the highest PAL values. Th e results also indicate that everyday activities such as walking and b icycling have a crucial impact on the PAL values. Conclusions: In the 15 y old adolescents of the two studied regions of Sweden, high and co ncordant levels of energy expenditure and physical activity were found .