Plain language summary
Prediabetes is a metabolic condition defined by elevated fasting (impaired fasting glucose) and/or postprandial (impaired glucose tolerance) plasma glucose. The aim of this study was to determine the effects of a single bout of resistance exercise on postprandial glucose metabolism following a mixed meal in obese, sedentary men with prediabetes. This study is a randomised, cross-over study design which enrolled ten participants. Participants were aged 39-62 years, obese, and demonstrated insulin resistance with compensatory increases in beta cell function. Results show that a single bout of resistance exercise performed 4.5 hours before a mixed meal (as opposed to an oral glucose tolerance test) reduced total postprandial glucose appearance, increased insulin sensitivity, and reduced the glycaemic response to a mixed meal. However, it did not have effect on glucose oxidation in obese men with prediabetes. Improvements in insulin sensitivity were complemented by reduced postprandial insulin concentration. Authors conclude that further investigation is needed to elucidate how resistance exercise affects exogenous (meal) vs endogenous postprandial glucose metabolism, and if additional bouts of exercise (i.e. training) produce superior outcomes for this population.
Abstract
INTRODUCTION Prediabetes is a major risk factor for type 2 diabetes and cardiovascular diseases. Although resistance exercise (RE) is recommended for individuals with prediabetes, the effects of RE on postprandial glucose metabolism in this population are poorly understood. Therefore, the purpose of this study was to elucidate how RE affects postprandial glucose kinetics, insulin sensitivity, beta cell function, and glucose oxidation during the subsequent meal in sedentary men with obesity and prediabetes. METHODS We studied 10 sedentary men with obesity (body mass index, 33 ± 3 kg·m-2) and prediabetes by using a randomized, cross-over study design. After an overnight fast, participants completed either a single bout of whole-body RE (seven exercises, 3 sets of 10-12 repetitions at 80% one-repetition maximum each) or an equivalent period of rest. Participants subsequently completed a mixed meal test in conjunction with an intravenous [6,6-2H2]glucose infusion to determine basal and postprandial glucose rate of appearance (Ra) and disappearance (Rd) from plasma, insulin sensitivity, and the insulinogenic index (a measure of beta cell function). Skeletal muscle biopsies were obtained 90 min postmeal to evaluate pyruvate-supported and maximal mitochondrial respiration. Whole-body carbohydrate oxidation was assessed using indirect calorimetry. RESULTS RE significantly reduced the postprandial rise in glucose Ra and plasma glucose concentration. Postprandial insulin sensitivity was significantly greater after RE, whereas postprandial plasma insulin concentration was significantly reduced. RE had no effect on the insulinogenic index, postprandial pyruvate respiration, or carbohydrate oxidation. CONCLUSION/INTERPRETATION A single bout of RE has beneficial effects on postprandial glucose metabolism in men with obesity and prediabetes by increasing postprandial insulin sensitivity, reducing the postprandial rise in glucose Ra, and reducing postprandial plasma insulin concentration.
Methodological quality
Jadad score
:
2
Allocation concealment
:
Yes
