Physical Activity and Sedentary Behavior Are Independently Associated with Weight in Korean Adolescents

BACKGROUND This study examines the relationship between physical activity (PA), sedentary behavior (SB) and body weight in Korean adolescents. METHODS This study used a nationally representative sample of 72,368 South Korean adolescents, aged 13 to 18 years. The study sample was categorized according to BMI as follows: underweight, body mass index (BMI) <18.5; normal weight, 18.5 ≤ BMI < 23.0; overweight, 23.0 ≤ BMI < 25.0; and obese, 25.0 ≤ BMI. An analysis was then performed to determine if meeting the recommended guidelines for PA frequency (5 times/week ≤) and amount of SB (<2 hours/day) was associated with weight category. RESULTS The percentage of normal weight adolescents was 54.3% while the percentages of underweight, overweight, and obese adolescents were 27.4%, 10.2%, and 8.1%, respectively. Significantly fewer underweight and obese adolescents met PA guidelines compared to normal weight adolescents. In addition, underweight, overweight, and obese adolescents had significantly higher SB scores. CONCLUSION The present study indicates that in Korean adolescents, physical activity and sedentary behavior are independently associated with weight status. Overweight, obese and underweight Korean adolescents should all be independently monitored for management of health-related behaviors.