When it comes to childhood and adolescent obesity, diet and exercise have long been considered as the first step towards treatment. However, a recent study from the University of Pittsburgh School of Medicine has shown that the type of exercise that females engage in has significant effects on certain risk factors more than others. According to the Centers for Disease Control and Prevention, in the US, childhood obesity has more than doubled and adolescent obesity has almost tripled in the past 30 years. The relevance of this research is therefore paramount in helping children and adolescents reduce their risk for developing obesity-related diseases such as type-2 diabetes, metabolic syndrome, and non-alcoholic fatty liver disease.
The study, led by SoJung Lee, was a follow up to their previous one that showed that when obese adolescent males increased their level of physical activity, they showed improvements in several aspects that are used to indicate health. The specific markers that were measured were total fat, visceral fat (fat that is packed around the internal organs and abdomen), liver fat, and general cardiovascular and respiratory health. To assess whether the effect was the same in young females, Lee and her colleagues tested two types of exercise, aerobic and weight lifting. While both types show an overall beneficial effect, the study reveals females who performed aerobic exercise and not weight lifting had significantly greater reductions in measures such as visceral fat, liver fat, and insulin sensitivity.
44 obese females between 12-18 years old volunteered for the study and the researchers divided them into three groups for analysis. One group was asked to perform 60 minutes of aerobic exercise (running on a treadmill or using an elliptical machine) three times a week, another was asked to perform 60 minutes of resistance exercise (10 whole body resistance exercises using weight machines) three times a week, and one group was asked not to participate in any structured exercise program for the course of the study. Each volunteer underwent a detailed physical examination prior to the start of each groups assignments. The researchers measured total fat, visceral fat, liver fat, fat embedded in musculature, insulin sensitivity, weight, and general cardiovascular and respiratory fitness.
Their results showed that while both groups engaged in exercise programs had less total fat and intramuscular fat than the control group by the end of the three-month study period, they were quite different in other measures. Generally, females in the aerobic exercise group lost visceral and liver fat and improved their insulin sensitivity. However, participants in the other groups didn’t.
The study, hence, suggests that tackling teen obesity in females is a little more complex than simply asking young girls to go out and be active and eat healthy. The sensitivity to the type of exercise not only affects the results, but also the level of enjoyment experienced by young girls. The researchers noted that girls in the aerobic exercise group claimed to enjoy their workouts more than the girls in the resistance group. This finding was the opposite of what the previous study concerning males showed. Boys seemed to enjoy the resistance workout more than the aerobic one. Given that the results allude to both psychologically and physiologically different results, this study can help address the issues of increasing childhood and adolescent obesity in a more focused way.
The article, “Aerobic Exercise But Not Resistance Exercise Reduces Intrahepatic Lipid Content and Visceral Fat and Improves Insulin Sensitivity in Obese Adolescent Girls” can be found in the online edition of the American Journal of Physiology-Endocrinology and Metabolism, published by the American Physiological Society.