Exercising for Insulin Sensitivity – Is There a Mechanistic Relationship With Quantitative Changes in Skeletal Muscle Mass?

Abstract

Skeletal muscle (SM) tissue has been repetitively shown to play a major role in whole-body glucose homeostasis and overall metabolic health. Hence, SM hypertrophy through resistance training (RT) has been suggested to be favorable to glucose homeostasis in different populations, from young healthy to type 2 diabetic (T2D) individuals. While RT has been shown to contribute to improved metabolic health, including insulin sensitivity surrogates, in multiple studies, a universal understanding of a mechanistic explanation is currently lacking. Furthermore, exercised-improved glucose homeostasis and quantitative changes of SM mass have been hypothesized to be concurrent but not necessarily causally associated. With a straightforward focus on exercise interventions, this narrative review aims to highlight the current level of evidence of the impact of SM hypertrophy on glucose homeostasis, as well various mechanisms that are likely to explain those effects. These mechanistic insights could provide a strengthened rationale for future research assessing alternative RT strategies to the current classical modalities, such as low-load, high repetition RT or high-volume circuit-style RT, in metabolically impaired populations.

Effects of Diet, Lifestyle, Chrononutrition and Alternative Dietary Interventions on Postprandial Glycemia and Insulin Resistance

“…As these authors [233] conclude, regular resistance exercise improves insulin sensitivity by a number of mechanisms, including greater muscle vascularization and increases in blood flow rates. However, the question if the beneficial effects of resistance exercise are due mostly to muscle hypertrophy or to a better quality of muscle cells needs further investigation [233].…”

“…It has been suggested that the increase in insulin-stimulated glucose disposal with resistance exercise may be due, at least in part, to the increase in muscle mass, whereas aerobic training may enhance insulin sensitivity by changes in the intrinsic metabolic pathways in muscle cells [232]. In a comprehensive recent narrative review, Paquin et al, summarized all the available literature on this subject aiming to provide a mechanistic explanation for this type of exercise in improving insulin sensitivity and health outcomes [233]. As these authors [233] conclude, regular resistance exercise improves insulin sensitivity by a number of mechanisms, including greater muscle vascularization and increases in blood flow rates.…”

“…In a comprehensive recent narrative review, Paquin et al, summarized all the available literature on this subject aiming to provide a mechanistic explanation for this type of exercise in improving insulin sensitivity and health outcomes [233]. As these authors [233] conclude, regular resistance exercise improves insulin sensitivity by a number of mechanisms, including greater muscle vascularization and increases in blood flow rates. However, the question if the beneficial effects of resistance exercise are due mostly to muscle hypertrophy or to a better quality of muscle cells needs further investigation [233].…”

Link between Insulin Resistance and Obesity—From Diagnosis to Treatment

“…In addition, it increases insulin sensitivity because the extra muscle mass requires greater utilization of glucose without the participation of insulin during exercise. Interestingly, the combination of aerobic and resistance training has been shown to translate into an almost 20% better effect than either regimen on its own [ 46 , 47 ]. Increasing the intensity of exercise, including high intensity interval training (HIIT), may result in a greater increase in cardiorespiratory fitness and achieve similar benefits more quickly than moderate-intensity aerobic exercise.…”

Long noncoding RNAs in cardiometabolic disorders

“…The pancreas is involved in central and peripheral glucose metabolism by secreting insulin and maintaining normal blood glucose levels [16]. Skeletal muscle plays an important role in systemic glucose homeostasis [17], and adipose tissue acts not only on lipid storage and thermogenesis but also on releasing factors regulating the overall body metabolism [18]. Fine-tuning of these physiological processes ensures their proper function.…”