The researchers assert that findings from a variety of studies of juvenile obesity in humans show that children who are inactive in childhood are significantly more likely than those who engaged in exercise when young to continue this habit into adulthood. Additionally, they say, this inactivity in childhood initiates the mechanisms that lead to the consequences of obesity seen in adults. Using the wheel lock model and other animal models for studying childhood obesity is giving scientists more insight on exactly what happens when activity is restricted during youth, leading to obesity. For example, studies have shown that young, inactive rats have reduced insulin sensitivity (a precursor to type-2 diabetes), eat more and burn off fewer calories, and develop larger fat pads than animals who continue to exercise. Other studies show that fat cells multiply to a significantly greater extent in rats who aren't allowed to run on their wheels, while others show that such voluntary exercise in parents can stem positive transgenerational effects in offspring that are bred to be genetically predisposed to obesity (for instance, reduced body fat). Additionally, the wheel lock and other animal model suggest that exercise during youth may help preserve muscle mass over the course of aging and lower the activity of genes associated with cardiovascular disease.
Importance of the Findings
The authors suggest that the wheel lock model and other models that allow exercise, then block it later, are akin to modern-day living conditions in which children who are active during the summer become increasingly sedentary when the school year starts. For these children, voluntary exercise abruptly ends when they must ride in motorized vehicles to school, sit in classrooms, and have insufficient recess or physical education classes. By studying these conditions in rats and other animals, Roberts and his colleagues say, researchers can avo
|Contact: Donna Krupa|
American Physiological Society