The acute vs. chronic effect of exercise on insulin sensitivity: nothing lasts forever.

Regular exercise causes chronic adaptations in anatomy/physiology that provide first-line defense for disease prevention/treatment ('exercise is medicine'). However, transient changes in function that occur following each exercise bout (acute effect) are also important to consider. For example, in contrast to chronic adaptations, the effect of exercise on insulin sensitivity is predominantly rooted in a prolonged acute effect (PAE) that can last up to 72 h. Untrained individuals and individuals with lower insulin sensitivity benefit more from this effect and even trained individuals with high insulin sensitivity restore most of a detraining-induced loss following one session of resumed training. Consequently, exercise to combat insulin resistance that begins the pathological journey to cardiometabolic diseases including type 2 diabetes (T2D) should be prescribed with precision to elicit a PAE on insulin sensitivity to serve as a first-line defense prior to pharmaceutical intervention or, when such intervention is necessary, a potential adjunct to it. Video Abstract: http://links.lww.com/CAEN/A27.