Under pressure to exercise: a cross-sectional study of characteristics and predictors of compulsive exercise in early adolescents

BACKGROUND: To investigate the frequency of compulsive exercise among early adolescents, and determine the associated impact of sex, physical activity level, exercise habits, motivational regulation, dieting behaviour and health-related quality of life (HRQoL) on compulsive exercise. METHODS: Cross-sectional design with 8th grade adolescents (n = 572, mean ± SD age 13.9 ± 0.3 yrs). Outcome assessment was compulsive exercise (Compulsive Exercise Test, CET). Total CET score ≥ 15 was defined as clinical CET score. Further assessment included exercise motivation (Behavioural Regulation of Exercise Questionnaire—2), HRQoL (KIDSCREEN 27), accelerometer-assessed physical activity and Andersen test for cardiorespiratory fitness. Exercise obsession was defined as clinical CET score and < 60 min/day with moderate-to-vigorous objectively assessed physical activity. RESULTS: Small sex differences were found for CET total score. Seven percent of the adolescents were classified with clinical CET score, and four percent with exercise obsession. Adolescents with clinical CET score had higher body mass index, more weight loss attempts, and lower physical fitness compared to adolescents with non-clinical CET score. Being a boy, higher scores on introjected motivational regulation and HRQOL subscale parent relation and autonomy, use of exercise monitoring tool, and number of weight loss attempt the past 12 months explained 39% of the total CET score variance. Physical activity level did not predict compulsive exercise. CONCLUSIONS: Compulsive exercise in early adolescents was predicted by exercise motivation, exercise habit, and dieting, but not physical activity level. This implicates a distinction of obsessive cognitions about physical activity from performed physical activity in adolescents, and that such cognitions must be addressed in future initiatives that aim to improve adolescents’ general physical activity level, health, and wellbeing. Trial registration ClinicalTrials.gov: NCT03906851. PLAIN ENGLISH SUMMARY: Although there is a huge concern about adolescents being insufficiently physically active, there are also adolescents who struggle with issues of compulsive exercise. The issues of compulsive exercise have been rarely studied in adolescents. We therefore aimed to describe compulsive exercise and factors that were associated with and could explain presence of compulsive exercise. A total of 572 8th graders (age 13.9 ± 0.3 yrs) responded to this study. We found that the score on compulsive exercise was higher in boys than in girls, and that adolescents with high score on compulsive exercise had higher body mass index, more weight loss attempts, and lower physical fitness compared to adolescents with low score on compulsive exercise. Also, we found that exercise obsessions, i.e., thinking of exercise without actually exercising, was present in four percent of the respondents. Being a boy, attempting weight loss, exercising to avoid shame/guilt, and exercising for the perceived value of exercise predicted compulsive exercise. Awareness of the compulsive exercise and exercise obsessions is important in public health initiatives that aim to increase adolescents’ physical activity level.