Aerobic Training Effects on Glucose Tolerance in Prediabetic and Normoglycemic Humans
ABSTRACT It is generally accepted that if prediabetic individuals adopt healthy lifestyle habits, the progression to type 2 diabetes mellitus can be prevented or delayed. However, the role of exercise training independent of other lifestyle factors has not been determined. Furthermore, patients with type 2 diabetes mellitus have been shown to experience greater training-induced changes in glucose and insulin metabolism compared with healthy subjects, but the adaptations of prediabetic individuals have not been adequately examined. We hypothesized that (i) prediabetic subjects would have greater endurance training-induced changes in plasma glucose and insulin responses to an oral glucose challenge compared with age- and body mass index-matched normoglycemic subjects and (ii) training would completely reverse the abnormal glucose metabolism of prediabetic subjects.
Plasma glucose and insulin responses to oral glucose tolerance tests (OGTTs) were examined in normoglycemic (n = 119) and prediabetic (n = 47) older men and women before and after a 6-month standardized endurance exercise training program.
Prediabetic subjects had greater glucose and insulin OGTT responses than normoglycemic subjects both before and after training (P < 0.05). Prediabetic subjects had greater training-induced changes in glucose and insulin areas under the glucose tolerance curve, as well as greater changes in glucose and insulin concentrations at several points of the OGTT. However, these changes did not eliminate the baseline differences in glucose tolerance between normoglycemic and prediabetic subjects. The between-group differences in changes in glucose and insulin variables were largely independent of changes in body weight or composition.
Our data indicate that prediabetes is associated with greater training-induced changes in glucose tolerance. However, 6 months of endurance training alone was not sufficient to completely reverse prediabetes.
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- "In an aerobic exercise intervention that utilized a progressive increase in intensity (i.e., 50 to 70% of VO 2max ) over a 6 month period with 3 exercise sessions per week, there was no weight loss but the intervention did promote significant reductions in intra-abdominal fat (-10 ± 4.0%) and subcutaneous fat (-15 ± 7.3%) which resulted in an approximate 5% reduction in glucose area under the curve (AUC) (Jenkins et al. 2011). Additionally, these changes in body composition promoted a 16% reduction in HOMA-IR scores within the same individuals (Jenkins et al. 2011). In a similar intervention that utilized vigorous intensity exercise (65% of VO 2peak ) but progressively increased the sessions per week (3 to 5 sessions) and duration per session (30 to 60 minutes), weight reduction did not occur. "
ABSTRACT: There is a general perception that increased physical activity will improve glucose homeostasis in all individuals. While this is an attractive concept, this conclusion may be overly simplistic and even misleading. The topic was reviewed extensively over 30 years ago and it was concluded that acute exercise enhances glucose uptake. However, in some cases the chronic influence of interventions utilizing exercise may have little effect on glucose metabolism. Moreover, insulin resistance often returns to near baseline levels within a couple of days following cessation of the exercise bout; leaving the overall effectiveness of the intervention in question. Since improving glucose homeostasis should be the focal endpoint of any intervention designed to mitigate the overwhelming degree of insulin resistance in individuals at risk for metabolic disease, it is essential to evaluate the key components of a successful approach.
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- "Overall, a modest improvement in glucose tolerance was only evident when considering changes in tAUC while excluding one subject (S10) who had a notable decrease in glucose tolerance after HIIT intervention. Indeed, subjects with insulin resistance have been reported to derive a greater training-induced change in glucose tolerance than age and BMI-matched normoglycemic controls25, with men having larger improvements in insulin sensitivity than women26. In our case, there was no significant change in weight or insulin sensitivity after short-term HIIT intervention, however modest decreases in abdominal %fat were associated with improvements in insulin area under the curve12. "
ABSTRACT: High-intensity interval training (HIIT) offers a practical approach for enhancing cardiorespiratory fitness, however its role in improving glucose regulation among sedentary yet normoglycemic women remains unclear. Herein, multi-segment injection capillary electrophoresis-mass spectrometry is used as a high-throughput platform in metabolomics to assess dynamic responses of overweight/obese women (BMI > 25, n = 11) to standardized oral glucose tolerance tests (OGTTs) performed before and after a 6-week HIIT intervention. Various statistical methods were used to classify plasma metabolic signatures associated with post-prandial glucose and/or training status when using a repeated measures/cross-over study design. Branched-chain/aromatic amino acids and other intermediates of urea cycle and carnitine metabolism decreased over time in plasma after oral glucose loading. Adaptive exercise-induced changes to plasma thiol redox and orthinine status were measured for trained subjects while at rest in a fasting state. A multi-linear regression model was developed to predict changes in glucose tolerance based on a panel of plasma metabolites measured for naïve subjects in their untrained state. Since treatment outcomes to physical activity are variable between-subjects, prognostic markers offer a novel approach to screen for potential negative responders while designing lifestyle modifications that maximize the salutary benefits of exercise for diabetes prevention on an individual level.Scientific Reports 08/2014; 4:6166. DOI:10.1038/srep06166 · 5.58 Impact Factor
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- "Therefore, natural antidiabetic drugs from medicinal plants have attracted a great deal of attention (Yeh et al. 2003; Kirkham et al. 2009; Petersen et al. 2011; Poraj-Kobielska et al. 2011). Admittedly, diabetes is a metabolic disorder which should be controlled or prevented with appropriate lifestyle adaptations including exercise, appropriate food and healthrelevant environments (Ianculov et al. 2010; Chaufan et al. 2011; Jenkins and Hagberg 2011; Smith et al. 2012). Indeed healthy foods rich in various medicinal properties provide a means to good health (Milner 2000; de Mello et al. 2011). "
ABSTRACT: Fungal Diversity, 56 (1), 1-29 (2012). Diabetes mellitus is a life-threatening chronic metabolic disease caused by lack of insulin and/or insulin dysfunction, characterized by high levels of glucose in the blood (hyperglycemia). Millions worldwide suffer from diabetes and its complications. Significantly, it has been recognized that type 2 diabetes is an important preventable disease and can be avoided or delayed by lifestyle intervention. Presently, there are many chemical and biochemical hypoglycemic agents (synthetic drugs), that are used in treating diabetes and are effective in controlling hyperglycemia. However, as they may have harmful side-effects and fail to significantly alter the course of diabetic complications, natural anti-diabetic drugs from medicinal plants have attracted a great deal of attention. Medicinal mushrooms have been valued as a traditional source of natural bioactive compounds over many centuries and have been targeted as potential hypoglycemic and anti-diabetic agents. Bioactive metabolites including polysaccharides, proteins, dietary fibres, and many other biomolecules isolated from medicinal mushrooms and their cultured mycelia have been shown to be successful in diabetes treatment as biological antihyperglycemic agents. In this review we discuss the biological nature of diabetes and, in particular, explore some promising mushrooms that have experimental anti-diabetic properties, preventing or reducing the development of diabetes mellitus. The importance of medicinal mushrooms as agents of medical nutrition therapy and how their metabolites can be used as supportive candidates for prevention and control of diabetes is explored. Future prospects for this field of study and the difficulties and constraints that might affect the development of rational drug products from medicinal mushrooms are discussed.Fungal diversity 09/2012; 56(56):1-29. DOI:10.1007/s13225-012-0187-4 · 6.22 Impact Factor