INS and type 2 diabetes mellitus: John Holloszy’s studies found that exercise improved insulin sensitivity in patients with type 2 diabetes and provided a better understanding of how muscle adapts to endurance exercise (Holloszy, 2005; Holloszy et al., 1986; Greiwe et al., 1999; Kirwan et al., 2009; Rogers et al., 1988; Hansen et al., 1998).