Although regular exercise increases cardiorespiratory fitness, improves insulin function, and reduces risk of diabetes-related complications, children with T1DM tend to be less physically active than their healthy peers (Valerio et al., 2007) and so can be less physically fit (e.g., lower VO2max and muscle strength; Lukács et al., 2012; Galassetti and Riddell, 2013). The gene discussed is INS; the disease is type 1 diabetes mellitus.