Assessing the evidence: Exploring the effects of exercise on diabetic microcirculation

Abstract

Diabetes mellitus (DM) is associated with cardiovascular complications. Impairment of glycemic control induces noxious glycations, an increase in oxydative stress and dearangement of various metabolic pathways. DM leads to dysfunction of micro- and macrovessels, connected to metabolic, endothelial and autonomic nervous system. Thus, assessing vascular reactivity might be one of the clinical tools to evaluate the impact of harmful effects of DM and potential benefit of treatment; skin and skeletal muscle microcirculation have usually been tested. Physical exercise improves vascular dysfunction through various mechanisms, and is regarded as an additional effective treatment strategy of DM as it positively impacts glycemic control, improves insulin sensitivity and glucose uptake in the target tissues, thus affecting glucose and lipid metabolism, and increases the endothelium dependent vasodilation. Yet, not all patients respond in the same way so titrating the exercise type individualy would be desirable. Resistance training has, apart from aerobic one, been shown to positively correlate to glycemic control, and improve vascular reactivity. It has been prescribed in various forms or in combination with aerobic training. This review would assess the impact of different modes of exercise, the mechanisms involved, and its potential positive and negative effects on treating patients with Type I and Type II DM, focusing on the recent literature.

Exercise training and endothelial function in patients with type 2 diabetes: a meta-analysis

“…In addition to suggesting a positive influence of exercise training on endothelial function in patients with type 2 diabetes, our study showed that the improvement in endothelial function in response to chronic exercise training was weakened in patients with type 2 diabetes compared with those without. Although the exact mechanism is not well understood, it is speculated that the presence of diabetes may compromise the ability of the endothelium to endogenously increase vascular nitric oxide bioavailability following exercise training [ 31 ], possibly because of the persistent hyperglycemia and the increased levels of circulating advanced glycation end products or reactive oxygen species [ 46 , 47 ]. Moreover, the blunted potential of exercise to stimulate and to mobilize endothelial progenitor cells observed in diabetic patients compared with non-diabetic controls might also contribute to the weakened improvement in endothelial function in response to exercise among type 2 diabetes [ 46 ].…”

“…Although the exact mechanism is not well understood, it is speculated that the presence of diabetes may compromise the ability of the endothelium to endogenously increase vascular nitric oxide bioavailability following exercise training [ 31 ], possibly because of the persistent hyperglycemia and the increased levels of circulating advanced glycation end products or reactive oxygen species [ 46 , 47 ]. Moreover, the blunted potential of exercise to stimulate and to mobilize endothelial progenitor cells observed in diabetic patients compared with non-diabetic controls might also contribute to the weakened improvement in endothelial function in response to exercise among type 2 diabetes [ 46 ]. These may indicate that more interventions apart from promoting physical exercise might be needed for patients with type 2 diabetes to obtain comparable health benefits like healthy or non-diabetic controls.…”

“…Secondly, most of the included studies implemented exercise interventions within 12 weeks, which largely represents a relatively short-term effect on endothelial function, although our meta-regression analysis suggested that intervention periods were not likely to affect the changes in endothelial function associated with exercise training. More studies are therefore warranted to explore the long-term (e.g., over 6 months) effects of exercise training on endothelial function, just as suggested by Lenasi and colleagues [ 46 ]. Thirdly, some variances existed in the measurement methods for FMD.…”

Acute strength training promotes responses in whole blood circulating levels of miR-146a among older adults with type 2 diabetes mellitus

“… 4 , 5 This condition is usually a direct result of a combination of genetic predisposition, physical inactivity, and poor eating habits. 6 , 7 …”

“…There is strong evidence in the literature 6 , 10 showing that physical activity helps in glycemic control by improving tissue sensitivity to insulin and reducing body weight. Increased blood glucose uptake by muscles may also result from enhanced action of the insulin-regulated GLUT4.…”