Glycemic and Metabolic Effects of Two Long Bouts of Moderate-Intensity Exercise in Men with Normal Glucose Tolerance or Type 2 Diabetes

BackgroundThe glycemic and insulinemic responses following 30–60 min of exercise have been extensively studied, and a dose–response has been proposed between exercise duration, or volume, and improvements in glucose tolerance or insulin sensitivity. However, few studies have examined the effects of longer bouts of exercise in type 2 diabetes (T2D). Longer bouts may have a greater potential to affect glucagon, interleukin-6 (IL-6) and incretin hormones [i.e., glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP)].AimTo examine the effect of two bouts of long-duration, moderate-intensity exercise on incretins, glucagon, and IL-6 responses before and after exercise, as well as in response to an oral glucose tolerance test (OGTT) conducted the following day.MethodsTwelve men, six with and six without T2D, participated in two separate conditions (i.e., exercise vs. rest) according to a randomized crossover design. On day 1, participants either rested or performed two 90 min bouts of treadmill exercise (separated by 3.5 h) at 80% of their ventilatory threshold. All participants received standardized meals on day 1. On day 2 of each condition, glucose and hormonal responses were measured during a 4-h OGTT.ResultsOn day 1, exercise increased IL-6 at the end of the first bout of exercise (exercise by time interaction p = 0.03) and GIP overall (main effect of exercise p = 0.004). Glucose was reduced to a greater extent in T2D following exercise (exercise by T2D interaction p = 0.03). On day 2, GIP and active GLP-1 were increased in the fasting state (p = 0.05 and p = 0.03, respectively), while plasma insulin and glucagon concentrations were reduced during the OGTT (p = 0.01 and p = 0.02, respectively) in the exercise compared to the rest condition for both healthy controls and T2D. Postprandial glucose was elevated in T2D compared to healthy control (p < 0.05) but was not affected by exercise.ConclusionLong-duration, moderate-intensity aerobic exercise can increase IL-6. On the day following exercise, fasting incretins remained increased but postprandial insulin and glucagon were decreased without affecting postprandial glucose. This long duration of exercise may not be appropriate for some people, and further research should investigate why next day glucose tolerance was unchanged

Exercise in type 2 diabetes mellitus: A meta-analysis of the effects of exercise on glycemic control, body composition and physical fitness.

The purpose of the study was to systematically review and quantify the effect of exercise interventions on HbAlc and body mass in type 2 diabetes. A literature search was conducted to find all controlled clinical trials in type 2 diabetic adults comparing an exercise intervention (≥8 weeks) to a non-exercise control. Weighted mean differences (WMD) and standardised mean differences (SMD) were used to calculate the size of the effect of exercise. Eleven aerobic training studies (average: 3.5 times/week for 18.6 weeks) and 2 resistance training studies (average: 10 exercises, 2.5 sets, 13 repetitions, 2.5 times/week for 15 weeks) met the inclusion criteria. In the first set of analyses, the effects of exercise on HbAlc and body mass were studied. Aerobic training interventions produced a significant decrease in HbAIc compared to control (WMD = -0.74, p = 0.00003). Improvements in HbAlc with resistance training were similar in size (WMD = -0.64, p = 0.05). Although the exercise groups lost a mean of 2.5 kilograms, their post-intervention body mass was not statistically different from the control groups' (SMD = 0.10 standard deviations (SD), p = 0.76). In the second set of analyses, aerobic training produced a 11% increase in VO 2 max compared to control (SMD = 0.49 SD, p = 0.003). When only intense aerobic interventions are considered (≥75% VO2 max) the post-intervention VO2 max was 30% higher than in the control group. Improvements in strength produced by resistance training were also significant (SMD = 1.00, p = 0.0001). In summary, exercise training resulted in statistically and clinically significant improvements in HbAIc without change in body mass compared to control. On the other hand, there is little information available from controlled clinical trials on the effect of exercise on other elements of body composition and physical fitness in type 2 diabetes

Physical activity preferences and type 2 diabetes: exploring demographic, cognitive, and behavioral differences

Purpose: The purpose of this study was to examine physical activity counseling and program preferences in a sample of adults with type 2 diabetes. Specifically, the objectives were to determine physical activity preferences (objective 1), and whether there were any significant differences between age and/or sex groups for these preferences (objective 1a). A subsidiary objective was to explore potential associations of key social-cognitive constructs (ie, self-efficacy and social support) with physical activity preferences (objective 2). Methods: This exploratory study consisted of a quantitative, secondary analysis of survey data from a national sample of adults with type 2 diabetes (N = 244). A qualitative follow-up employing telephone interviews was conducted with 14 individuals. Results: Consistent with hypotheses, walking was the most preferred physical activity behavior and there was a preference for engaging in physical activity with others. There were significant (P values < .05) differences in counseling and program preferences between demographic (age and sex), and physical activity cognitive scores. For example, a significantly (P < .05) higher physical activity intensity preference was found in men and younger participants. Conclusions: Tailoring interventions and physical activity programs to the specific preferences of individuals is an important component for health professionals and researchers in facilitating this behavior

Associations between physical activity, screen time, and fitness among 6- to 10-year old children living in Edmonton, Canada

The objectives of this study were to describe fitness levels, examine associations between physical activity (PA), screen time (ST), and fitness, and examine sex moderating effects in a sample of children. Participants were 649 children (7.8±0.6years; 52.4% female) from Edmonton, Canada. Hours/week of PA and ST were parent-reported. PA was also objectively measured with pedometers and expressed in increments of 1000 steps/day. Fitness components (i.e., vertical jump, sit-and-reach, waist circumference, grip strength, predicted maximal oxygen consumption (VO₂ max), push-ups, partial curl-ups, overall fitness) were measured according to the Canadian PA, Fitness and Lifestyle Approach protocols and expressed as z-scores or low/high fitness. Positive associations were observed between PA and overall fitness for both the complete (Subjective: β=0.009, 95%CI: 0.001, 0.017) and partial (≥3 available fitness measures; Subjective: β=0.006, 95%CI: 0.000, 0.011; Objective: β=0.025, 95%CI: 0.007, 0.042) fitness scores. Subjective (β=0.011, 95%CI: 0.000, 0.022) and objective (β=0.043, 95% CI: 0.008, 0.078) PA were positively associated with vertical jump. Children with higher objective PA were more likely to be in the high push-ups group (OR=1.156, 95%CI: 1.054, 1.267). PA was positively associated with predicted VO₂ max (Subjective: β=0.040, 95%CI: 0.018, 0.063; Objective: β=0.084, 95%CI: 0.012, 0.157) and grip strength (Subjective: β=0.025, 95%CI: 0.011, 0.040) in boys only. ST was negatively associated with grip strength (β=-0.016, 95%CI: -0.028, -0.004) in boys. PA was associated with several components of fitness, especially in boys. However, few associations were observed between ST and fitness. Promoting regular PA in young children may address declining fitness levels.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

The Effect of Starting Blood Glucose Levels on Serum Electrolyte Concentrations during and after Exercise in Type 1 Diabetes

Fear of hypoglycemia is a major exercise barrier for people with type 1 diabetes (PWT1D). Consequently, although guidelines recommend starting exercise with blood glucose (BG) concentration at 7&ndash;10 mmol/L, PWT1D often start higher, potentially affecting hydration and serum electrolyte concentrations. To test this, we examined serum and urine electrolyte concentrations during aerobic exercise (cycling 45 min at 60%VO2peak) in 12 PWT1D (10F/2M, mean &plusmn; SEM: age 29 &plusmn; 2.3 years, VO2peak 37.9 &plusmn; 2.2 mL&middot;kg&minus;1&middot;min&minus;1) with starting BG levels: 8&ndash;10 (MOD), and 12&ndash;14 (HI) mmol/L. Age, sex, and fitness-matched controls without diabetes (CON) completed one exercise session with BG in the normal physiological range. Serum glucose was significantly higher during exercise and recovery in HI versus MOD (p = 0.0002 and p &lt; 0.0001, respectively) and in MOD versus CON (p &lt; 0.0001). During exercise and recovery, MOD and HI were not significantly different in serum insulin (p = 0.59 and p = 0.63), sodium (p = 0.058 and p = 0.08), potassium (p = 0.17 and p = 0.16), calcium (p = 0.75 and 0.19), and magnesium p = 0.24 and p = 0.09). Our findings suggest that exercise of moderate intensity and duration with higher BG levels may not pose an immediate risk to hydration or serum electrolyte concentrations for PWT1D

Exploring the Variability in Acute Glycemic Responses to Exercise in Type 2 Diabetes

Aim. To explore the factors associated with exercise-induced acute capillary glucose (CapBG) changes in individuals with type 2 diabetes (T2D). Methods. Fifteen individuals with T2D were randomly assigned to energy-matched high intensity interval exercise (HI-IE) and moderate intensity continuous exercise (MI-CE) interventions and performed a designated exercise protocol 5 days per week for 12 weeks. The duration of exercise progressed from 30 to 60 minutes. CapBG was measured immediately before and after each exercise session. Timing of food and antihyperglycemic medication intake prior to exercise was recorded. Results. Overall, the mean CapBG was lowered by 1.9 mmol/L (P<0.001) with the change ranging from −8.9 to +2.7 mmol/L. Preexercise CapBG (44%; P<0.001), medication (5%; P<0.001), food intake (4%; P=0.043), exercise duration (5%; P<0.001), and exercise intensity (1%; P=0.007) were all associated with CapBG changes, explaining 59% of the variability. Conclusion. The greater reduction in CapBG seen in individuals with higher preexercise CapBG may suggest the importance of exercise in the population with elevated glycemia. Lower blood glucose can be achieved with moderate intensity exercise, but prolonging exercise duration and/or including brief bouts of intense exercise accentuate the reduction, which can further be magnified by performing exercise after meals and antihyperglycemic medication. This trial is registered with ClinicalTrial.gov NCT01144078

Additional file 1 of Effects of supervised high-intensity interval training on motivational outcomes in men with prostate cancer undergoing active surveillance: results from a randomized controlled trial

Additional file 1. Supplementary material-CONSORT diagram

Examining the effects of a high-protein total diet replacement on energy metabolism, metabolic blood markers, and appetite sensations in healthy adults: protocol for two complementary, randomized, controlled, crossover trials

Abstract Background High-protein diets and total diet replacements are becoming increasingly popular for weight regulation; however, further research is needed to elucidate their impact on the physiology of body weight regulation. The aim of this inpatient metabolic balance study is to compare the impact of a high-protein total diet replacement versus a control diet (North American) on energy expenditure, macronutrient oxidation rates and balances, metabolic blood markers and appetite sensations in healthy adults. Methods Two randomized, controlled, cross-over clinical trials conducted separately in men and women will be conducted. In each trial, participants will be allocated to two isocaloric arms: a) Control diet: 55% carbohydrate, 15% protein, and 30% fat; b) High-protein total diet replacement: 35% of carbohydrate, 40% protein, and 25% fat. They will receive the prescribed diets for 32 h while inside the whole-body calorimetry unit. Diets will be designed to ensure participants are in energy balance. The following physiological changes will be compared between groups: energy expenditure, macronutrient oxidation rates and balances, metabolic blood markers, and appetite sensations. Body composition will be assessed at baseline using dual-energy X-ray absorptiometry. Discussion This will be the first inpatient metabolic balance study examining the impact of a high-protein total diet replacement on energy metabolism, metabolic blood markers and appetite sensations in healthy young adults (of both sexes) using a whole-body calorimetry unit. Results of this clinical trial can ultimately be used to develop strategies to optimize high-protein diet interventions and weight management. Trial registration ClinicalTrials.gov Identifiers: NCT02811276 (registered on 16 June 2016) and NCT03565510 (registered on 11 June 2018). Protocol version NCT02811276: version 10 (2 March 2018); NCT03565510: version 3 (28 September 2018)

Exercise during and after neoadjuvant rectal cancer treatment (the EXERT trial): study protocol for a randomized controlled trial

Abstract Background Standard treatment for locally advanced rectal cancer includes 5–6 weeks of neoadjuvant chemoradiotherapy (NACRT) followed by total mesorectal excision 6–8 weeks later. NACRT improves local disease control and surgical outcomes but also causes side effects including fatigue, diarrhea, hand-foot syndrome, and physical deconditioning that may impede quality of life (QoL), treatment completion, treatment response, and long-term prognosis. Interventions to improve treatment outcomes and manage side effects that are safe, tolerable and low-cost are highly desirable. Exercise has been shown to improve some of these outcomes in other cancer patient groups but no study to date has examined the potential benefits (and harms) of exercise training during and after NACRT for rectal cancer. Methods/design The Exercise During and After Neoadjuvant Rectal Cancer Treatment (EXERT) trial is a single-center, prospective, two-armed, phase II randomized controlled trial designed to test the preliminary efficacy of exercise training in this clinical setting and to further evaluate its feasibility and safety. Participants will be 60 rectal cancer patients scheduled to receive long-course NACRT followed by total mesorectal excision. Participants will be randomly assigned to exercise training or usual care. Participants in the exercise training group will be asked to complete three supervised, high-intensity interval training sessions/week during NACRT and ≥ 150 min/week of unsupervised, moderate-to-vigorous-intensity, continuous exercise training after NACRT prior to surgery. Participants in the usual care group will be asked not to increase their exercise from baseline. Assessments will be completed pre NACRT, post NACRT, and pre surgery. The primary endpoint will be cardiorespiratory fitness (VO2 peak) at the post-NACRT time point assessed by a graded exercise test. Secondary endpoints will include functional fitness assessed by the Senior’s Fitness Test, QoL assessed by the European Organisation of Research and Treatment of Cancer, and symptom management assessed by the M.D. Anderson Symptom Inventory. Exploratory clinical endpoints will include treatment toxicities, treatment completion, treatment response, and surgical complications. Discussion If the preliminary findings of EXERT are positive, additional research will be warranted to confirm whether exercise is an innovative treatment to maintain QoL, manage side effects, and/or improve treatment outcomes in rectal cancer patients. Trial registration ClinicalTrials.gov, ID: NCT03082495 . Registered on 9 February, 2017