The effects of physical exercise on physical fitness and executive function in children with excessive body weight

Abstract Objective: The purpose of this study was to evaluate the impact of 11 weeks physical exercises on physical fitness and executive functions in children with excessive body weight. Methods: In the first phase, 61 six-year-old children were divided into 3 groups according to the degree of obesity: 17 in the normal weight group (NW), 24 in the overweight group (OW), 20 in the obesity group (OB). In the second phase, 56 participants from the first phase who wished to participate in the exercise program were divided into 3 groups as described above. The physical exercise program lasted 40 minutes daily, 4 days a week for 11 weeks, including 5 min warm-up exercise, 30-min physical exercise training and 5 min cool-down stage. Then, all participants were tested before and after the experiment for body composition, physical fitness, executive functions and saliva analysis test. Body composition was measured by height, weight, body mass index (BMI), and percentage of body fat (%BF). Physical fitness was measured by cardiopulmonary fitness, muscle strength, speed sensitivity, and flexibility quality. Executive function was measured by animal go/no-go task, working memory span task, simple reaction test and flexible item selection task. Saliva GH and IGF-I concentrations was assayed with Human IGF-I ELISA. Results: Apart from height, all parameters measuring body composition were higher in the obesity group than in the other groups (p < 0.05). Moreover, physical fitness and executive function also were significantly worse in the overweight and obesity groups compared with the normal group (p < 0.05). SalivaGH and IGF-I was significantly lower in the obesity group than in the normal and overweight groups(p < 0.0001), but did not differ between the normal and overweight groups ( p >0.001). After exercise intervention, no statistical difference of upper limb muscular strength among three groups (p > 0.05). Among physical fitness variables, the lower limb muscular strength, flexibility quality, speed sensitivity, and cardiopulmonary were significantly improved in the overweight group (p < 0.05); All executive function parameter were higher in the normal and overweight groups than obesity group, except for cognitive flexibility, such as inhibitory control, working memory, and reaction time (p < 0.05). in addition, physical exercise significantly increased saliva GH and IGF-I concentrations in children with obesity (p < 0.05). Conclusion: 11-week physical exercise can improve the physical fitness and executive functions of 6-year-old overweight children. Furthermore, the findings were positively associated with the degree of obesity. Thus, our study highlights the importance of exercise prescription for the effective prevention and treatment of childhood obesity considering the obesity degree.