Does type 2 diabetes duration influence the effectiveness of an aerobic exercise intervention: Results from the INTENSITY study.

BACKGROUND: Studies suggest that longer durations of T2DM increase the risk of T2DM complications and premature mortality. However, whether T2DM duration impacts the efficacy of an aerobic exercise intervention is unclear. OBJECTIVE: The purpose of this study was: 1) to compare changes in body composition, cardiorespiratory fitness, and glycemia between individuals with short- and long-duration T2DM after aerobic exercise and 2) to determine whether these changes were associated with changes in glycemia by T2DM duration. METHODS: A secondary analysis of the INTENSITY study (NCT03787836), including thirty-four adults (≥19 years) with T2DM who participated in 28 weeks of aerobic exercise training for 150 minutes per week at a moderate-to-vigorous intensity (4.5 to 6.0 metabolic equivalents (METs)). Using pre-established cut-points, participants were categorized into two groups 1) short-duration T2DM (<5 years) or 2) long-duration T2DM (≥5 years). Glycemia was measured by glycated hemoglobin (HbA1c), body composition by BodPod, and cardiorespiratory fitness by a measure of peak oxygen consumption (VO2peak). All measurements were performed at baseline, 16 weeks, and 28 weeks. RESULTS: Participants in the short-duration T2DM group experienced decreases in fat mass (kg) (p = 0.03), HbA1c (p = 0.05), and an increased relative VO2peak (p = 0.01). Those with long-duration T2DM experienced decreases in fat mass (kg) (p = 0.02) and HbA1c (p <0.001) and increased fat-free mass (p = 0.02). No significant differences were observed between groups in any outcomes. Changes in fat mass (r = 0.54, p = 0.02), and body fat percentage (r = 0.50, p = 0.02) were significantly associated with the change in HbA1c in those with a long-duration T2DM only. CONCLUSION: Our results suggest T2DM duration did not differently impact the efficacy of a 28-week aerobic exercise intervention. However, changes in body composition were associated with better glycemia in individuals with longer T2DM duration only.

Irisin response to acute moderate intensity exercise and high intensity interval training in youth of different obesity statuses: A randomized crossover trial.

Limited data exist regarding the impact of an acute bout of exercise with varying intensities on irisin levels in the youth of different obesity statuses. The objectives were to (1) compare an acute bout of moderate continuous intensity (MCI) exercise and an acute bout of high-intensity interval training (HIIT) on irisin response in youth with different obesity statuses and, (2) investigate whether changes in irisin levels are correlated with exploratory outcomes. A randomized crossover design study was conducted on 25 youth aged 12-18 years old. Participants were classified as either healthy weight (BMI percentile <85; n = 14) or overweight/obese (BMI percentile ≥85; n = 11). Participants performed an MCI exercise session at 50% of heart rate reserve for 35 min and a HIIT exercise session for 35 min, with intervals every 5 min increasing from 50% heart rate reserve to 85-90% for 2 min. Irisin was measured using an enzyme-linked immunoabsorbent assay from plasma sampling obtained throughout the exercise (at times 0, 7, 14, 21, 28, and 35 min). A time effect was observed throughout the HIIT session [F(1,5) = 6.478, p < 0.001]. Bonferonni post-hoc analysis revealed significant differences in irisin levels post-exercise (35 min) compared to times 7, 14, 21, and 28 min. Irisin increased during HIIT (81.0% ± 71.3; p = 0.012) in youth with a healthy weight. No differences were observed for youth living as overweight or with obesity. Overall, HIIT elicits a higher peak irisin response compared to MCI exercise training in youth.

Exploring the Association of a Total Physical Activity Energy Expenditure and Diabetes Mellitus in Adults: A Cross-Sectional Analysis of the Canadian Health Measures Survey.

Background: Physical activity (PA) guidelines for adults recommend participation in aerobic activities of moderate-to-vigorous intensity and a minimum of two sessions of resistance training (RT) weekly. These guidelines account for a small amount of the total PA energy expenditure and include no recommendation for low intensity activities (sleeping, sedentary behavior, and light intensity PA). Consequently, there is a need to investigate the benefits of total PA energy expenditure and diabetes mellitus (DM); to investigate the association between total PA energy expenditure and DM in adults aged 45 years or above. Methods: Data from the Canadian Health Measures Survey (CHMS; n = 5591) were used for the cross-sectional analysis. DM was measured using hemoglobin glycated (A1c) and questionnaires in adults aged 45 and above. PA and sedentary behavior were estimated using accelerometry. Sleep and RT were self-reported. Total PA energy expenditure was computed using the sum of metabolic equivalent of task-min/week. Results: The mean age of the sample was 58.0 ± 0.2 years old. No associations were observed between total PA energy expenditure and self-reported T2DM in all models (P > 0.05). For objectively measured DM, this association was significant when adjusted for age, sex, ethnicity, and smoking [OR: 0.45; 95% CI (0.25-0.80)]; however, the association was no longer significant once adjusted for waist circumference and further adjusted for meeting the International PA Guidelines [OR: 0.64; 95% CI (0.33-1.27)] (P > 0.05). Conclusion: Total PA energy expenditure performed weekly is not associated with DM when considering other known risk factors, including waist circumference and meeting the PA guidelines.

Impact of acute circuit training on irisin in younger and older overweight adults.

Studies show aerobic exercise increases irisin and leads to health benefits. The impact of circuit training (CT) on irisin in overweight younger and older adults is unknown. The objectives were to determine whether, during an acute bout of CT, changes in irisin differed between overweight younger and older adults, and if irisin is associated with body composition, fitness level, or muscle strength. Inactive, overweight adults aged between 19-35 (25.9 ± 5.0; n = 15) and 60-75 years (67.7 ± 4.1; n = 14) participated in this study. The primary exposure variable was an acute bout of CT (12-15 repetitions; 65-70% of 1-repetition maximum; 3 loops). The primary outcome measure was the concentration of irisin determined by ELISA before, during, and after exercise. Repeated-measures analyses showed no effect of time on irisin levels during acute CT, and no interaction effect between age and time (p > 0.05). No associations were observed between changes in irisin and body composition, fitness, or strength (p > 0.05). In conclusion, acute CT does not increase irisin in overweight individuals, and irisin is not associated with the measured outcomes. Further studies are needed to elucidate the release of irisin by different types of exercise across the lifespan. This trial was registered at clinicaltrials.gov (NCT03715088). Novelty: Younger and older adults show a similar irisin response to an acute bout of circuit training. Irisin response is not associated with measures of body composition, cardiorespiratory fitness, or muscle strength.

Outdoor Time is Not Associated with Metabolically Healthy Overweight and Obesity Phenotype in Canadian Children Aged 6-14 Years.

A large proportion of children living with obesity have favorable cardiometabolic profiles despite their adiposity levels, who are referred to as metabolically healthy overweight or obese (MHO). However, the contribution of active outdoor time to the MHO phenotype is unknown. The purpose of this study was to investigate the association between outdoor time and moderate-to-vigorous physical activity (MVPA) with the MHO phenotype. A cross-sectional analysis of overweight/obese children aged 6-14 (n = 386) from the Canadian Health Measures Survey was performed. Outdoor time was self-reported using five questions in relation to the school schedule to produce a computed score ranging from 0-25. MVPA was measured using accelerometers. The MHO phenotype was defined based on the absence of cardiometabolic risk factors: triglycerides, HDL-cholesterol, systolic and diastolic blood pressure, and glucose (MHO: 0 cardiometabolic risk factors). The proportion of children living with obesity with the MHO phenotype was 58.5%. No significant differences were observed between MHO and non-MHO according to outdoor time or MVPA (p > 0.05). Logistic regressions indicated that outdoor time was not significantly associated with the MHO phenotype (OR: 0.99, 95% CI = 0.92-1.06; p = 0.694), while MVPA was significantly associated with the MHO phenotype (OR: 1.41, 95% CI = 1.01-1.98; p = 0.047) after adjusting for confounders. We conclude that outdoor time is not associated with the MHO phenotype, even though Canadian children living with obesity are more likely to be MHO with greater amounts of MVPA, regardless of whether these activities are completed outdoors or not.

Physical Activity and Sedentary Patterns among Metabolically Healthy Individuals Living with Obesity.

BACKGROUND: Some individuals living with obesity are free from typical cardiometabolic risk factors and are termed metabolically healthy obese (MHO). The patterns of physical activity and sedentary behaviors among MHO are currently unknown. METHODS: This study includes 414 youth (12-18 years old), 802 adults (19-44 years old), and 1230 older adults (45-85 years old) living with obesity from the 2003-2004 or 2005-2006 NHANES cycles. Time spent in bouts of 1, 5, 10, 30, and 60 minutes for moderate-to-vigorous physical activity (MVPA) and sedentary time was measured objectively using accelerometers. Participants were categorized as MHO if they had no cardiometabolic risk factors above the identified thresholds (triglycerides, high-density lipoprotein cholesterol, systolic blood pressure, diastolic blood pressure, and glucose). RESULTS: The proportion of MHO was 19%, 14%, and 12% in youth, adults, and older adults, respectively. MHO adults displayed a higher 1-minute bout of MVPA per day compared to non-MHO (p = 0.02), but no difference was observed for MVPA and sedentary behavior patterns for youth and older adults. When adjusted for confounders, all bouts of sedentary behavior patterns in youth were significantly associated with being classified as MHO. CONCLUSION: This study suggests that greater sedentary time is associated with cardiometabolic risk factors in youth even if they are physically active.

Exercise-induced irisin release as a determinant of the metabolic response to exercise training in obese youth: the EXIT trial.

The mechanisms underlying the metabolic improvements following aerobic exercise training remain poorly understood. The primary aim of this study was to determine if an adipomyokine, irisin, responded to acute exercise was associated with the metabolic adaptations to chronic aerobic exercise in obese youth. The acute response to exercise was assessed in 11 obese youth following 45-min acute bouts of aerobic (AE) and resistance exercise (RE). The irisin area under the curve (pre-exercise, 15, 30, and 45 min) during these AE sessions were the main exposure variables. The primary outcome measure was the change in insulin sensitivity using the Matsuda index, following 6 weeks of RE training, delivered for 45 min, three times per week at 60-65% 1RM. Participants were also categorized as either responders (above) or nonresponders (below) based on the percentage change in the Matsuda index following the 6-week intervention. Irisin increased significantly during the acute bout of AE from 29.23 ± 6.96 to 39.30 ± 7.05 ng/mL; P = 0.028, but not significantly during the RE session (P = 0.182). Absolute and relative change in irisin during the acute bout of AE was associated with absolute and relative change in Matsuda index (r = 0.68; P = 0.022 and r = 0.63; P = 0.037) following the 6-week RE intervention. No such association was observed with the irisin response to acute RE (all P > 0.05). Responders to the 6-week RE intervention displayed a fourfold greater irisin response to acute AE (90.0 ± 28.0% vs. 22.8 ± 18.7%; P = 0.024) compared to nonresponders. Irisin increases significantly following an acute bout of AE, but not RE, and this response is associated with a greater improvement in insulin sensitivity in response to chronic resistance training.

Association between Functional Movements Skills and Health Indicators in Children Aged between 9 and 12 Years Old.

Background: Children's health is a current concern and data suggests that poor fundamental movement skills (FMS) could be associated with poor health, which may or may not be mediated by low physical activity level. However, tools to assess FMS have not been standardized, and could consequently lead to different associations between FMS and health indicators. Objective: The primary objective of this study was to evaluate the associations between FMS and health indicators using two different FMS measurement tools often used in Canada. Methods: A total of 145 children between the ages of 9 to 12 were recruited from schools, after school programs, and summer camps in 2016. FMS were evaluated using the Passport for Life (bound, plank, run, kick, throw) and the PLAYbasic (run, hop, throw, kick, and balance). The association between each test and an average score for each tool were tests with health indicators including anthropometric measures, grip strength, cardiorespiratory fitness, and percent body fat. Results: Participants were composed of 54.2% boys aged 10.4 ± 1.2 years with an average body mass index of 18.8 ± 3.8 kg/m². The association between the average score of both tools was 0.77 (p < 0.01), body mass index was significantly associated with 67% of FMS elements using the Passport for Life (r ranging from -0.18 to -0.32; p < 0.05), and 60% of FMS using the PLAYbasic (r ranging from -0.15 to -0.30; p < 0.05). There were no significant differences between the associations of the health indicators with FMS and either FMS assessment tool (Passport for Life and PLAYbasic) (p = 0.05). Average score of FMS was significantly associated with all health indicators using both PLAYbasic and Passport for Life (all p < 0.05). Conclusions: Health indicators in children are associated with FMS regardless of whether the Passport for Life or the PLAYbasic was used as the assessment tool. It is worth investigating if interventions that improve FMS lead to improvements in these health indicators.

Association Between Handgrip Muscle Strength and Cardiometabolic z-Score in Children 6 to 19 Years of Age: Results from the Canadian Health Measures Survey.

BACKGROUND: It is unclear if muscle strength, another index of fitness, which confers the protection from cardiometabolic risk in adults, is associated with similar protection in children and youth. The purpose of this study was to investigate the association between handgrip strength and cardiometabolic health in a large Canadian sample of children and youth. METHODS: We performed a cross-sectional analysis of the Canadian sample of children and youth aged 6 to 19 years (n = 1376) studied in the Canadian Health Measures Survey (cycles 1 and 2) between 2007 and 2011. The primary exposure variable, handgrip strength, was measured using a handgrip dynamometer. The primary outcome measure was a composite measure of cardiometabolic risk calculated as the sum of z-scores of the following variables: triglycerides, low high-density lipoprotein cholesterol, systolic and diastolic blood pressures, and hemoglobin A1c. All of the analyses were adjusted for confounders. RESULTS: The sample was on average 12.8 ± 3.5 years and displayed a body mass index (BMI) z-score of 0.5 ± 1.2. In unadjusted analyses, handgrip strength was negatively associated with cardiometabolic z-score (estimate = -0.013; P < 0.001). When results were adjusted for age, BMI z-score, and cardiorespiratory fitness, the association was no longer significant; however, an interaction between handgrip strength, sex, and cardiometabolic z-score was observed (estimate = -0.042; P < 0.001). When analyses were stratified by sex, handgrip strength was negatively associated with cardiometabolic z-score (estimate = -0.038; P < 0.001) in girls, but not in boys (estimate = 0.008; P = 0.150). CONCLUSION: In a large sample of Canadian children and adolescents, handgrip strength was associated with cardiometabolic health in girls, but not in boys.

Association Between Physical Activity Intensity and Physical Capacity Among Individuals Awaiting Bariatric Surgery.

BACKGROUND: Physical activity is a routine component of the lifestyle modification program implemented prior to bariatric surgery, and one of the goals is to improve patients' physical capacity. However, the physical activity intensity recommended to meet that goal is unknown. OBJECTIVE: This study aimed to assess the association between time spent at different physical activity intensities and physical capacity in patients awaiting bariatric surgery. MATERIALS AND METHODS: A total of 39 women and 13 men were recruited. The primary outcome was physical capacity measured using six objective tests: 6-min walk, chair stand, sit and reach, unipodal balance (eyes open and eyes closed), and hand grip strength tests. The primary exposure variable was physical activity intensity (i.e., sedentary, light, moderate, and vigorous) measured by accelerometers. RESULTS: The average body mass index was 46.3 ± 5.4 kg/m2. Only 6% of total time was spent at moderate to vigorous intensity, while 71% of the time was spent sedentary. When adjusted for body mass index, age, and sex, four of the six physical capacity tests were significantly associated with moderate intensity physical activity ß(SE): 6-min walk 9.7 (2.7), chair stand 0.3 (0.1), balance (eyes open) 1.8 (0.7), and hand grip strength 1.2 (0.4), and only the 6-min walk was associated with sedentary activity 1.7 (0.7). CONCLUSION: These results suggest that physical capacity is associated with time spent at moderate intensity in individuals awaiting bariatric surgery. The next step is to study if an increase in time spent at moderate intensity will translate to improvements in physical capacity.