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Muscle glucose transport activity increases with an acute bout of exercise, a process that is accomplished by the translocation of glucose transporters to the plasma membrane. This process remains intact in the skeletal muscle of individuals with insulin resistance and type 2 diabetes mellitus (T2DM). Exercise training is, therefore, an important cornerstone in the management of individuals with T2DM. However, the acute systemic glucose responses to carbohydrate ingestion are often augmented during the early recovery period from exercise, despite increased glucose uptake into skeletal muscle. Accordingly, the first aim of this review is to summarize the knowledge associated with insulin action and glucose uptake in skeletal muscle and apply these to explain the disparate responses between systemic and localized glucose responses post-exercise. Herein, the importance of muscle glycogen depletion and the key glucoregulatory hormones will be discussed. Glucose uptake can also be stimulated independently by hypoxia; therefore, hypoxic training presents as an emerging method for enhancing the effects of exercise on glucose regulation. Thus, the second aim of this review is to discuss the potential for systemic hypoxia to enhance the effects of exercise on glucose regulation. [ABSTRACT FROM AUTHOR]

Purpose: This study examined the effect of graded hypoxia during exhaustive intermittent cycling on subsequent exercise performance and neuromuscular fatigue characteristics in normoxia. Methods: Fifteen well-trained cyclists performed an exhaustive intermittent cycling exercise (EICE 1; 15 s at 30% of anaerobic power reserve interspersed with 45 s of passive recovery) at sea level (SL; FiO2 ~ 0.21), moderate (MH; FiO2 ~ 0.16) and severe hypoxia (SH; FiO2 ~ 0.12). This was followed, after 30 min of passive recovery in normoxia, by an identical exercise bout in normoxia (EICE 2). Neuromuscular function of the knee extensors was assessed at baseline, after EICE 1 (post-EICE 1), and EICE 2 (post-EICE 2). Results: The number of efforts completed decreased with increasing hypoxic severity during EICE 1 (SL: 39 ± 30, MH: 22 ± 13, SH: 13 ± 6; p ≤ 0.02), whereas there was no difference between conditions during EICE 2 (SL: 16 ± 9, MH: 20 ± 14, SH: 24 ± 17; p ≥ 0.09). Maximal torque (p = 0.007), peripheral (p = 0.02) and cortical voluntary activation (p < 0.001), and twitch torque (p < 0.001) decreased from baseline to post-EICE 1. Overall, there were no significant difference in any neuromuscular parameters from post-EICE 1 to post-EICE 2 (p ≥ 0.08). Conclusion: Increasing hypoxia severity during exhaustive intermittent cycling hampered exercise capacity, but did not influence performance and associated neuromuscular responses during a subsequent bout of exercise in normoxia performed after 30 min of rest. [ABSTRACT FROM AUTHOR]

Background/Objectives:The purpose of the current study was to determine whether increased physical activity (PA) altered glycemic control while ingesting an energy-balanced high-fructose diet.Subjects/Methods:Twenty-two normal-weight men and women (age: 21.2±0.6 years; body mass index: 22.6 ±0.6 kg/m2) participated in a randomized, cross-over design study in which they ingested an additional 75 g of fructose for 14 days while either maintaining low PA (FR+inactive) (<4500 steps/day) or high PA (FR+active) (>12 000 steps/day). Before and following the 2-week loading period, a fructose-rich meal challenge was administered and blood was sampled at baseline and for 6 h after the meal and analyzed for glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), c-peptide, glucose and insulin concentrations.Results:Plasma insulin, glucose, c-peptide, GIP and GLP-1 concentrations significantly increased in response to the test meal on all test visits (P<0.05). C-peptide incremental area under the curve (AUC) decreased by 10 208 ±120 pmol/l × min for 6 h from pre to post Fr+active intervention (P=0.02) leading to a decrease in plasma insulin total AUC (pre: 58 470.2±6261.0 pmol/l; post: 49 444.3±3883.0 pmol/l; P=0.04) resulting in a decrease Δpeak[Insulin] (P=0.009). Following the FR+active intervention, GIP total AUC significantly decreased (P=0.005) yet only males had a lower total GLP-1 AUC after both interventions (P=0.049). There were no sex differences in GIP levels.Conclusions:Increased PA attenuates the deleterious effects on glycemic control caused by a high-fructose diet. These changes in glycemic control with PA are associated with decreases in insulin and GIP concentrations. [ABSTRACT FROM AUTHOR]

Objective:To examine the acute effects of high-intensity intermittent exercise (HIIE) on energy intake, perceptions of appetite and appetite-related hormones in sedentary, overweight men.Design:Seventeen overweight men (body mass index: 27.7±1.6 kg m−2; body mass: 89.8±10.1 kg; body fat: 30.0±4.3%; VO2peak: 39.2±4.8 ml kg−1 min−1) completed four 30-min experimental conditions using a randomised counterbalanced design. CON: resting control, MC: continuous moderate-intensity exercise (60% VO2peak), HI: high-intensity intermittent exercise (alternating 60 s at 100% VO2peak and 240 s at 50% VO2peak), VHI: very-high-intensity intermittent exercise (alternating 15 s at 170% VO2peak and 60 s at 32% VO2peak). Participants consumed a standard caloric meal following exercise/CON and an ad-libitum meal 70 min later. Capillary blood was sampled and perceived appetite assessed at regular time intervals throughout the session. Free-living energy intake and physical activity levels for the experimental day and the day after were also assessed.Results:Ad-libitum energy intake was lower after HI and VHI compared with CON (P=0.038 and P=0.004, respectively), and VHI was also lower than MC (P=0.028). Free-living energy intake in the subsequent 38 h remained less after VHI compared with CON and MC (P0.050). These observations were associated with lower active ghrelin (P0.050), higher blood lactate (P0.014) and higher blood glucose (P0.020) after VHI compared with all other trials. Despite higher heart rate and ratings of perceived exertion (RPE) during HI and VHI compared with MC (P0.004), ratings of physical activity enjoyment were similar between all the exercise trials (P=0.593). No differences were found in perceived appetite between trials.Conclusions:High-intensity intermittent exercise suppresses subsequent ad-libitum energy intake in overweight inactive men. This format of exercise was found to be well tolerated in an overweight population. [ABSTRACT FROM AUTHOR]

Objective:Short-term exercise training improves glycemic control, but the effect of short-term training on postprandial satiety peptide responses or perceived satiety remains unknown. We tested the hypothesis that short-term aerobic exercise training (15 days) would alter postprandial pancreatic and gut peptide (pancreatic polypeptide (PP) and peptide YY (PYY)) responses and perceived appetite and satiety in obese individuals.Subjects:Thirteen healthy obese men and women (age: 42±2 years; body mass index: 30-45 kg m−2).Measurements:Subjects were studied before and after 15 days of training (walking 1 h at 70-75% VO2peak). On the study day, subjects consumed 1500 kcal as six meals (250 kcal: 9 g protein, 40 g carbohydrate, 6 g fat), while blood samples and satiety measurements were taken at baseline and every 20 min for 12 h. Blood was analyzed for PP, PYY, glucose and insulin levels. Appetite and satiety was assessed with a visual analog scale throughout the day.Results:Incremental area under the curve (iAUC) for PP increased significantly with training (pre: 2788±753; post: 3845±830 pg ml−1·per min for 12 h; P<0.001), but there was no difference in the PP response to each meal. The initial PP response to the first meal increased (ΔPPmin 20-0: pre 86±25; post 140±36 pg ml−1; P<0.05) with training. PYY iAUC showed no significant changes with training but showed a significant main effect of time across meals, with the largest response being to the first meal (P<0.005). There were no changes in satiety, glucose or insulin levels with training.Conclusion:Short-term exercise training increases postprandial PP concentrations in obese individuals; however, PYY levels and glycemic control remain unaffected. Both PP and PYY show meal-induced increases at all meals, but PYY has a greater response at the first meal with reduced responses at subsequent meals. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Post-Exercise Energy Load and Activities May Affect Subsequent Ad Libitum Energy Intake" by D. Thivel and colleagues in the 2014 issue.