Relationship between objectively measured physical activity, sedentary behaviour and body mass index among 11-13 year-old adolescents in Colombo

Abstract

INTRODUCTION & OBJECTIVES: Inadequate physical activity (PA) and sedentary behaviour (SB) are attributed to the high prevalence of adolescent obesity in the world. This study aimed to identify the relationship between PA intensity, SB and body mass index (BMI) among I I -13 year-old adolescents in Colombo, Sri Lanka. METHODS: A purposive sample of 95 adolescent school girls and boys were recruited from the Colombo Municipal Council Area. Time spent on moderate-to-vigorous PA (MVPA) and SB were determined by accelerometers (Actigraph-WGT3X-BT) worn on the waist for 10 consecutive days. Height and weight were measured using the standard methodology and BMI was calculated. RESULTS: The sample consisted of 51.6 % of boys (n=49). Mean BMI of the boys was 17.2 ± 3.2 kgm-2 and girls was 17.2 ± 3.2 kgm-2. A significantly (p< 0.05) lower SB (487.4 ± 101.4 min/day vs. 596.4 ± 83.8 min/day) and a significantly higher time spent on MVPA (31.8 ± 15.1 min/day vs. 15 ± 6.7 min/day) were observed among normal weight (NW) girls compared to overweight (OW) girls. Similarly, compared to the OW boys, NW boys had a significantly (p< 0.05) lower SB (578.5 ± 94.1 min/day vs. 696.4 ± 87.4 min/day) and a significantly higher time spent in MVPA (52.9 ± 19.3 min/day vs. 23.4 ± 6.3 min/day). CONCLUSION: Effective strategies should be implemented to reduce SB and increase PA in order to correct the obsogenic behaviour among the adolescents.