Physical activity levels, exercise intrinsic motivation, physical fitness, and their association with adiposity and Oxytocin Receptor (OXTR) rs53576 and rs2254298 gene variants

Intrinsic motivation predicts higher exercise participation and long-term sustenance. Common variants in the oxytocin receptor gene (OXTR) have been associated with socially-related personality traits and behaviours, and obesity pathogenesis. The study aims to investigate the association of physical activity (PA) level, intrinsic motivation, and physical fitness, with adiposity and OXTR rs53576 and rs2254298 among a sample of Malaysian urban young adults in Sunway University. A total of 273 participants (M/F = 118/155; aged 21.5 ± 2.9) self-reported their socio-demographics, PA levels via International Physical Activity Questionnaire (IPAQ) Short Form, and intrinsic motivation via Motives for Physical Activities Measure - Revised (MPAM-R). Physical fitness was assessed by three-minute step test, while anthropometric and body composition measurements were taken. Genotyping was performed by allele-specific real-time PCR. Men reported higher PA levels and higher Interest, Competence, and Social scores than women. Interest and Competence scores were significantly positively correlated with vigorous, moderate and total METs, and were also significantly associated with Waist-Height Ratio. Fitness was significantly associated with Waist-Hip Ratio. Physical fitness was significantly positively correlated with vigorous and total METs. OXTR rs53576 was significantly associated with Appearance only, but not PA levels, physical fitness, and adiposity. Men were more physically active and intrinsically more motivated to exercise than women. The desire to have fun and engage with challenges when exercising correlates with more frequent exercise, and is a predictor of lower adiposity. OXTR rs53576 influences motivation for being physically active in order to become more physically attractive.