Figure 1.

Graph depicting the hyperbolic relation between insulin secretion and insulin sensitivity. Insulin secretion rises as insulin sensitivity falls when an individual goes from a state of exercise training/being physically active (point A) to detraining/sedentary (point B) and vice versa, that is, bidirectionality of the two arrows from B to A when undergoing exercise training/increasing physical activity levels. A failure of insulin secretion to compensate for a fall in insulin sensitivity is noted when both insulin secretion and insulin sensitivity decline from points B to C, leading to elevated fasting glucose and prediabetes (impaired glucose tolerance). A progressive decline in both insulin secretion and insulin sensitivity to point D indicates type 2 diabetes. Adapted from reference (9) with permission.