A defined exercise program significantly improved cardiometabolic health and body composition in children with overweight and obesity, but no effect was seen on mental health, based on data from 92 children.
Childhood obesity is associated with negative health outcomes including type 2 diabetes, cardiovascular disease, and mental health disorders, and exercise is considered essential to treatment, wrote Jairo H. Migueles, PhD, of the University of Granada, Spain, and colleagues. However, the effect on children with obesity and overweight of an exercise program on physical and mental health, including within-individual changes, has not been well studied, they said.
In ain JAMA Network Open, the researchers reviewed data from 36 girls and 56 boys with overweight or obesity who were randomized to a 20-week exercise program with aerobic and resistance elements, or waitlisted to serve as controls. The participants ranged in age from 8 to 11 years with a mean age of 10 years. The data were collected between Nov. 1, 2014, and June 30, 2016, as part of a parallel-group randomized clinical trial. The exercise program consisted of three to five 90-minute exercise sessions per week for 20 weeks, and the control children continued their usual routines.
The main cardiometabolic outcomes measured in the study were divided into three categories: body composition, physical fitness, and traditional risk factors (waist circumference, blood lipid levels, glucose levels, insulin levels, and blood pressure).
A cardiometabolic risk score was defined by z score. The researchers also added cardiorespiratory fitness (CRF) to the cardiometabolic risk score. Mental health was assessed using composite standardized scores for psychological well-being and poor mental health.
After 20 weeks, cardiometabolic risk scores decreased by approximately 0.38 standard deviations in the exercise group compared with the control group. In addition, specific measures of cardiometabolic health improved significantly from baseline in the exercise group compared with control children for low-density lipoprotein (change of –7.00 mg/dL), body mass index (–5.9 kg/m2), fat mass index (−0.67), and visceral adipose tissue (31.44 g).
Cardiorespiratory fitness improved by 2.75 laps in the exercise group compared with control children. In addition, significantly more children in the exercise group showed meaningful changes (defined as individual changes of at least 0.2 SDs) compared with control children in measures of fat mass index (37 vs. 17, P < .001) and CRF performance (30 vs. 17, P = .03).
However, no significant effects appeared on mental health outcomes in exercisers, the researchers noted.
The reduction in cardiometabolic score was attributable mainly to improvements in cardiovascular fitness, blood lipid levels, and total and visceral adiposity, the researchers wrote in their discussion. The lack of changes in mental health measures may be a result of the healthy mental state of the children at the study outset, they said. “The null effect on mental health outcomes needs to be further investigated, including, among other things, whether the instruments are sensitive enough to detect changes and whether there is a ceiling effect in young children who might be mentally healthy overall,” they wrote.
The findings were limited by several factors, including the relatively small sample size and lack of blinding for some evaluators. However, the results show the potential of exercise programs to affect meaningful change and improve cardiometabolic health in overweight and obese children, although more research is needed to explore the effects of larger-scale and longer-lasting public health interventions combining exercise and other health behaviors such as diet, the researchers concluded.