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Objectives: To investigate the effects of aerobic training, resistance training, or both on abdominal subcutaneous fat (subcutaneous adipose tissue (SAT)) (deep and superficial), visceral fat (visceral adipose tissue (VAT)), apolipoproteins A-1 and B (ApoA-1, ApoB), ApoB/ApoA-1 ratio and high-sensitivity C-reactive protein (HSCRP) in post-pubertal adolescents with obesity., Participants: After a 4-week supervised moderate-intensity exercise run-in period, 304 postpubertal adolescents with overweight (body mass index (BMI) ⩾85th percentile for age and sex+diabetes risk factor) or obesity (⩾95th BMI percentile) aged 14-18 years were randomized to four groups for 22 weeks (5 months): aerobic training, resistance training, combined training or a non-exercising control., Methods: This study used a randomized controlled design. All groups received dietary counseling designed to promote healthy eating with a maximum daily energy deficit of 250 kcal. Abdominal fat (SAT and VAT) at the level of the fourth and fifth lumbar vertebrae (L4-L5) was measured by magnetic resonance imaging and ApoA-1, ApoB and HSCRP were measured after a 12-h fast at baseline and after 6 months., Results: Changes in SAT at L4-L5 were -16.2 cm(2) in aerobic (P=0.04 vs control), -22.7 cm(2) in resistance (P=0.009 vs control) and -18.7 cm(2) in combined (P=0.02 vs control). Combined training reduced ApoB levels from 0.81±0.02 to 0.78±0.02 g l(-1) (P=0.04 vs control) and ApoB/ApoA-1 ratio from 0.67±0.02 to 0.64±0.02 (P=0.02 vs control and P=0.04 vs aerobic). There were no significant differences in VAT, ApoA-1 or HSCRP levels between groups., Conclusions: Aerobic and resistance training and their combination decreased abdominal SAT in adolescents with obesity. Combined training caused greater improvements in ApoB/ApoA-1 ratio compared with aerobic training alone.

Recent data demonstrated that individuals with type 1 diabetes mellitus (T1DM) exhibit impaired sweating and increased rectal temperature (i.e., heat storage) during exercise compared with healthy controls. Our purpose in this study was to investigate the consequences of T1DM on post-exercise thermal homeostasis. Sixteen participants (eight controls matched with eight T1DM) performed 90 min of cycling followed by 60 min of seated recovery. Esophageal and rectal temperatures, sweating (forearm, chest, and upper back), skin blood flow [forearm and upper back, presented as cutaneous vascular conductance (CVC)], and blood pressure [mean arterial pressure (MAP)] were measured at baseline and throughout recovery. Esophageal temperature was similar during baseline and recovery between groups (P = 0.88). However, rectal temperature was elevated in our T1DM group throughout recovery (P = 0.05). Sweating and CVC were similar between groups at all sites from 10-min post-exercise until the end of recovery (P ≥ 0.16). While absolute MAP was similar between groups (P = 0.43), the overall decrease in MAP post-exercise was greater in controls from 20 min (T1DM: - 8 ± 5 vs control: - 13 ± 6 mmHg, P = 0.03) until the end of recovery. We conclude that despite increased heat storage during exercise, individuals with T1DM exhibit a suppression in heat loss similar to their healthy counterparts during recovery., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aerobic training is the most prescribed exercise modality for the management of pediatric obesity. There is strong evidence that it decreases waist circumference, percent body fat and visceral fat, increases cardiorespiratory fitness, and decreases blood pressure in obese adolescents. However, the independent effects of aerobic exercise training on other cardiometabolic risk factors (ie, insulin resistance markers, plasma lipid levels, and inflammatory markers) are limited and yield inconsistent findings. Our article reviews randomized controlled trials evaluating the effects of aerobic exercise training on body composition, fitness, lipid levels, and insulin resistance in obese adolescents (aged 13-18 years) and outlines future research directions for this population.

Purpose: The objective of the Healthy Eating Aerobic and Resistance Training in Youth (HEARTY) trial (ClinicalTrials.Gov # NCT00195858) was to examine the effects of resistance training, with and without aerobic training, on percent body fat in sedentary, post-pubertal overweight or obese adolescents aged 14-18 years. This paper describes the HEARTY study rationale, design and methods., Methods: After a 4-week supervised low-intensity exercise run-in period, 304 overweight or obese adolescents with a body mass index≥85th percentile for age and sex were randomized to 4 groups for 22 weeks (5 months): diet+aerobic exercise, diet+resistance exercise, diet+combined aerobic and resistance exercise, or a diet only waiting-list control. All participants received dietary counseling designed to promote healthy eating with a maximum daily energy deficit of -250 kcal., Outcomes: The primary outcome is percent body fat measured by Magnetic Resonance Imaging. Secondary outcomes include changes in anthropometry, regional body composition, resting energy expenditure, cardiorespiratory fitness, musculoskeletal fitness, cardiometabolic risk markers, and psychological health., Summary: To our knowledge, HEARTY is the largest clinical trial examining effects of aerobic training, resistance training, and combined aerobic and resistance training on changes in adiposity and cardiometabolic risk markers in overweight and obese adolescents. The findings will have important clinical implications regarding the role that resistance training should play in the management of adolescent obesity and its co-morbidities., (Copyright © 2012 Elsevier Inc. All rights reserved.)

A poor understanding of behaviour change mechanisms has hindered the development of effective physical activity interventions. The aim of this study was to identify potential mediators of change in a home-based resistance training (RT) program for obese individuals with type 2 diabetes. Obese individuals with type 2 diabetes (N = 48) were randomly allocated to either an RT intervention (n = 27) or a control group (n = 21) for the 16-week study period. The study sample included 16 men and 32 women and the mean age of participants was 54.4 (±11.7) years. Participants in the RT group received a multi-gym and dumbbells and home supervision from a certified personal trainer. RT behaviour was measured using a modified Godin Leisure Time Questionnaire. Social-cognitive constructs were measured and tested in a mediating variable framework using a product-of-coefficients test. The intervention had a significant effect on RT behaviour (p < 0.001) and muscular strength (p < 0.001). The intervention had a significant effect on RT planning strategies (p < 0.01), which mediated the effect of the intervention on RT behaviour. The home-based RT program successfully targeted participants' RT planning strategies which contributed to their exercise adherence.

Aims/hypothesis: The Diabetes Aerobic and Resistance Exercise (DARE) study showed that aerobic and resistance exercise training each improved glycaemic control and that a combination of both was superior to either type alone in patients with type 2 diabetes mellitus. Here we report effects on patient-reported health status and well-being in the DARE Trial., Methods: We randomised 218 inactive participants with type 2 diabetes mellitus in parallel to 22 weeks of aerobic exercise (n = 51), resistance exercise (n = 58), combined aerobic and resistance exercise (n = 57) or no exercise (control; n = 52). Intervention allocation was managed by a central office. Outcomes included health status as assessed by the physical and mental component scores of the Medical Outcomes Trust Short-Form 36-item version (SF-36) and well-being as measured by the Well-Being Questionnaire 12-item version (WBQ-12); these were measured at the Ottawa Hospital., Results: Using a p value of 0.0125 for statistical significance due to multiple comparisons, mixed model analyses indicated that resistance exercise led to clinically but not statistically significant improvements in the SF-36 physical component score compared with aerobic exercise (Delta = 2.7 points; p = 0.048) and control (i.e. no exercise; Delta = 3.3 points; p = 0.015). For mental component scores, there were clinically important improvements favouring no (control) compared with resistance (Delta = 7.6 points; p < 0.001) and combined (Delta = 7.2 points; p < 0.001) exercise. No effects on WBQ-12 scores were noted. Overall, 59/218 (27%) of participants included in this analysis sustained an adverse event during the course of the study, including 16 participants in the combined exercise group, 19 participants in the resistance exercise group, 16 participants in the aerobic exercise group, and eight participants in the control group. All participants were included in the intent-to-treat analyses. The trial is now closed to follow-up., Conclusions/interpretation: Resistance exercise was better than aerobic or no exercise for improving physical health status in these patients. No exercise was superior to resistance or combined exercise for improving mental health status. Well-being was unchanged by intervention., Trial Registration: ClinicalTrials.gov NCT00195884, Funding: This study was funded by the Canadian Institutes of Health Research (grant MCT-44155) and the Canadian Diabetes Association (The Lillian Hollefriend Grant).

Physical activity (PA) plays a key role in the management of Type 1 (T1D) and Type 2 diabetes (T2D) but there are few theory-based, effective programs to promote PA for individuals with diabetes. The purpose of this study was to investigate the utility of the Theory of Planned Behaviour (TPB) in understanding PA in an adult population with T1D or T2D. A total of 2311 individuals (691 T1D; 1614 T2D) completed self-report TPB constructs of attitude, subjective norms, perceived behavioural control (PBC), intention and PA at baseline and 1717 (524 T1D; 1123 T2D) completed the PA measure again at 6-month follow-up. Multi-group Structural Equation Modelling was conducted to: (1) test the fit of the TPB structure (2) determine the TPB structural invariance between the two types of diabetes and (3) to examine the explained variances in PA and compare the strength of associations of the TPB constructs in the two types of diabetes. The TPB constructs explained > or =40% of the variance in intentions for both diabetes groups. In cross-sectional models, the TPB accounted for 23 and 19% of the variance in PA for T1D and T2D, respectively. In prospective models, the TPB explained 13 and 8% of the variance in PA for T1D and T2D, respectively. When adjusting for past PA behaviour, the impact of PBC and intention on behaviour was reduced in both groups. The findings provide evidence for the utility of the TPB for the design of PA promotion interventions for adults with either T1D or T2D.

Aims/hypothesis: Exercise training improves glycaemic control in some but not all individuals and little research has been done regarding genetic impact on the exercise training response in type 2 diabetes. The purpose of this study was to investigate the influence of the Pro(12)Ala variant of the peroxisome proliferator-activated receptor (PPAR) gamma2 gene on changes in fasting plasma glucose in response to exercise training., Methods: The study population comprised 139 sedentary type 2 diabetic patients (age: 54.4+/-7.2; HbA(1)c: 7.7+/-0.9%) who completed 3 months of supervised exercise training. The primary outcome variable in our analysis was the post-intervention change in blood glucose. Other assessments included measures of body composition, insulin sensitivity indices and maximal oxygen uptake (VO(2max))., Results: The frequency of the Ala allele was 8.3% and the genotypes were in Hardy-Weinberg equilibrium. At baseline, neither body composition variables (weight, BMI, waist circumference), glucose homeostasis variables (glucose, insulin, HbA(1)c, homeostasis model assessment method) nor VO(2max) were different between genotypes (wild-type: Pro(12)Pro n=117, Ala carriers: X(12)Ala n=22). The exercise-training intervention led to similar improvements in body composition and glucose homeostasis variables in both genotype groups (p<0.05). The change in fasting plasma glucose was significantly different between PPARgamma2 genotypes (-1.66 mmol/l vs -0.54 mmol/l, Ala carriers and wild-type, respectively) (p=0.034 unadjusted and p=0.089 including baseline glucose) and the significant association between genotype and glucose response remained after adjusting for statistically significant predictors (age, changes in insulin and BMI [p=0.015]) and including baseline glucose, insulin and BMI (p=0.031)., Conclusions/interpretation: These data suggest that the Pro(12)Ala polymorphism may influence the glycaemic response to exercise in type 2 diabetes.

Context: Exercise is widely perceived to be beneficial for glycemic control and weight loss in patients with type 2 diabetes. However, clinical trials on the effects of exercise in patients with type 2 diabetes have had small sample sizes and conflicting results., Objective: To systematically review and quantify the effect of exercise on glycosylated hemoglobin (HbA(1c)) and body mass in patients with type 2 diabetes., Data Sources: Database searches of MEDLINE, EMBASE, Sport Discuss, Health Star, Dissertation Abstracts, and the Cochrane Controlled Trials Register for the period up to and including December 2000. Additional data sources included bibliographies of textbooks and articles identified by the database searches., Study Selection: We selected studies that evaluated the effects of exercise interventions (duration >/=8 weeks) in adults with type 2 diabetes. Fourteen (11 randomized and 3 nonrandomized) controlled trials were included. Studies that included drug cointerventions were excluded., Data Extraction: Two reviewers independently extracted baseline and postintervention means and SDs for the intervention and control groups. The characteristics of the exercise interventions and the methodological quality of the trials were also extracted., Data Synthesis: Twelve aerobic training studies (mean [SD], 3.4 [0.9] times/week for 18 [15] weeks) and 2 resistance training studies (mean [SD], 10 [0.7] exercises, 2.5 [0.7] sets, 13 [0.7] repetitions, 2.5 [0.4] times/week for 15 [10] weeks) were included in the analyses. The weighted mean postintervention HbA(1c) was lower in the exercise groups compared with the control groups (7.65% vs 8.31%; weighted mean difference, -0.66%; P<.001). The difference in postintervention body mass between exercise groups and control groups was not significant (83.02 kg vs 82.48 kg; weighted mean difference, 0.54; P =.76)., Conclusion: Exercise training reduces HbA(1c) by an amount that should decrease the risk of diabetic complications, but no significantly greater change in body mass was found when exercise groups were compared with control groups.

In intense exercise (>80% maximal oxygen consumption [VO2 max]), the 7- to 8-fold increase in glucose production (Ra) is tightly correlated with the greater than 14-fold increase in plasma norepinephrine (NE) and epinephrine (EPI). To distinguish the relative roles of alpha- and beta-adrenergic receptors, the responses of 12 control (C) lean, healthy, fit young male subjects to 87% VO2 max cycle ergometer exercise were compared with those of 7 subjects (at 83% VO2max) receiving intravenous phentolamine (Ph). The Ph group received a 70-microg/kg bolus and then 7 microg/kg/min from -30 minutes, during exercise and for 60 minutes of recovery. The data were analyzed by comparing exercise responses to exhaustion in Ph subjects (11.4 +/- 0.6 min) with those at both 12 minutes and at exhaustion in C subjects (14.6 +/- 0.3 min) and during recovery. There were no significant differences between groups in the plasma glucose response during exercise, but values were higher in C versus Ph subjects during the first 40 minutes of postexercise "recovery." The Ra response during the first 12 minutes of exercise was not different by repeated-measures ANOVA, reaching 10.6 +/- 1.3 mg/kg/min in C and 9.6 +/- 1.5 in Ph subjects at 12 minutes. However, in C subjects, Ra increased significantly to 14.1 +/- 1.2 mg/kg/min by exhaustion, and remained higher versus Ph subjects until 15 minutes of recovery. The Rd during recovery was not different between groups; thus, the higher Ra in C subjects in early recovery was responsible for the greater hyperglycemia observed in C subjects. Ph subjects showed a more rapid, marked increment (P = .002) in both plasma NE (to 64 v38 nmol/L) and EPI at exhaustion, and catecholamine concentrations remained higher in Ph versus C subjects during recovery. Whereas plasma insulin (IRI) declined in the C group, it increased 3-fold (P = .001) in the Ph group during exercise and until 15 minutes of recovery. Ph had no effect on glucagon (IRG). Thus, the glucagon to insulin ratio decreased in Ph subjects from baseline levels during exercise and early recovery, but increased in C subjects. The increase in Ra among Ph subjects despite the decrease in the glucagon to insulin ratio supports our earlier evidence that these hormones are not principal regulators of the Ra in intense exercise. The shorter time to exhaustion and markedly higher catecholamine levels in Ph subjects limited our ability to isolate the effects of alpha-adrenergic receptors on the Ra.alpha-Adrenergic receptors appear to have little influence on the Rd.

In intense exercise (>80% maximum oxygen uptake) a huge, up to 8-fold increase in glucose production (Ra) is tightly correlated to marked increases in plasma norepinephrine (NE) and epinephrine. Both Ra and glucose uptake (Rd) are enhanced, not reduced, during beta-adrenergic blockade in normal subjects. Beta-blockade also caused a greater fall in immunoreactive insulin (IRI) during exercise, which could, in turn, have increased Ra directly or via an increased glucagon/insulin ratio. To control for adrenergic effects on endogenous insulin secretion, we tested type 1 diabetic subjects (DM) made euglycemic by overnight i.v. insulin that was kept constant in rate during and after exercise. Their responses to postabsorptive cycle ergometer exercise at 85-87% maximum oxygen uptake for approximately 14 min were compared to those of similar male control (CP) subjects. Six DM and seven CP subjects received i.v. 150 microg/kg propranolol over 20 min, then 80 microg/kg x min from -30 min, during exercise and for 60 min during recovery. Plasma glucose increased from similar resting values to peaks of 6.8 mmol/L in DM and 6.5 mmol/L in CP, then returned to resting values in CP within 20 min, but in DM, remained higher than in CP from 8-60 min (P = 0.049). Ra rose rapidly until exhaustion, to 13.3 mg/kg x min in CP and 11.6 in DM (P = NS). Ra declined rapidly in recovery, although somewhat more slowly in DM (P = 0.013 from 2-15 min). The Rd increased to 10.6 in CP and 9.2 mg/kg x min in DM (P = NS), then declined similarly in early recovery, but remained higher in CP from 50-100 min (P = 0.05). The rises in plasma glucose during exercise in both groups were thus due to the increments in Rd less than those in Ra. The higher recovery glucose in DM was due to the slower decline in Ra and the lower Rd in later recovery. IRI was higher in DM than in CP before exercise (P = 0.011), and whereas it decreased in CP (P < 0.05), it increased approximately 2-fold in DM, thus being higher throughout exercise (P = 0.003). The glucagon/insulin ratio was unchanged in DM, but increased in CP during exercise (P = 0.002). NE showed a rapid, marked increment during exercise to peak values of 23.7 nmol/L in CP and 25.7 nmol/L in DM (P = NS), and epinephrine showed parallel responses. Both correlated significantly with the Ra responses. In summary, the Ra responses of both DM and CP during exercise were greater than those of control unblocked subjects (previously reported) despite higher IRI (all exogenous) in DM. This suggests an important contribution of direct alpha-adrenergic stimulation to this Ra effect.

Context: Although many studies suggest that physical activity may reduce risk of type 2 diabetes, the role of moderate-intensity activity such as walking is not well understood., Objectives: To examine the relationship of total physical activity and incidence of type 2 diabetes in women and to compare the benefits of walking vs vigorous activity as predictors of subsequent risk of type 2 diabetes., Design and Setting: The Nurses' Health Study, a prospective cohort study that included detailed data for physical activity from women surveyed in 11 US states in 1986, with updates in 1988 and 1992., Participants: A total of 70,102 female nurses aged 40 to 65 years who did not have diabetes, cardiovascular disease, or cancer at baseline (1986)., Main Outcome Measure: Risk of type 2 diabetes by quintile of metabolic equivalent task (MET) score, based on time spent per week on each of 8 common physical activities, including walking., Results: During 8 years of follow-up (534, 928 person-years), we documented 1419 incident cases of type 2 diabetes. After adjusting for age, smoking, alcohol use, history of hypertension, history of high cholesterol level, and other covariates, the relative risks (RRs) of developing type 2 diabetes across quintiles of physical activity (least to most) were 1.0, 0.77, 0.75, 0.62, and 0.54 (P for trend <.001); after adjusting for body mass index (BMI), RRs were 1.0, 0.84, 0.87, 0.77, and 0.74 (P for trend = .002). Among women who did not perform vigorous activity, multivariate RRs of type 2 diabetes across quintiles of MET score for walking were 1.0, 0.91,0.73, 0.69, and 0.58 (P for trend <.001). After adjusting for BMI, the trend remained statistically significant (RRs were 1.0, 0.95, 0.80, 0.81, 0.74; P for trend = .01). Faster usual walking pace was independently associated with decreased risk. Equivalent energy expenditures from walking and vigorous activity resulted in comparable magnitudes of risk reduction., Conclusions: Our data suggest that greater physical activity level is associated with substantial reduction in risk of type 2 diabetes, including physical activity of moderate intensity and duration.

Glucose infusion can prevent the increase in glucose production (Ra) and increase glucose uptake (Rd) during exercise of moderate intensity. We postulated that 1) because in postabsorptive intense exercise (>80% maximal O2 uptake) the eightfold increase in Ra may be mediated by catecholamines rather than by glucagon and insulin, exogenous glucose infusion would not prevent the Ra increment, and 2) such infusion would cause greater Rd. Fit young men were exercised at >85% maximal O2 uptake for 14 min in the postabsorptive state [controls (Con), n = 12] or at minute 210 of a 285-min glucose infusion. In seven subjects, the infusion was constant (CI; 4 mg . kg-1 . min-1), and in seven subjects it was varied (VI) to mimic the exercise Ra response in Con. Although glucose suppressed Ra to zero (with glycemia approximately 6 mM and insulin approximately 150 pM), an endogenous Ra response to exercise occurred, to peak increments two-thirds those in Con, in both CI and VI. Glucagon was unchanged, and very small increases in the glucagon-to-insulin ratio occurred in all three groups. Catecholamine responses were similar in all three groups, and correlation coefficients of Ra with plasma norepinephrine and epinephrine were significant in all. In all CI and VI, Rd at rest was 2x Con, increased earlier in exercise, and was higher for the 1 h of recovery with glucose infusion. Thus the Ra response was only partly attenuated, and the catecholamines are likely to be the regulators. This suggests that an acute endogenous Ra rise is possible even in the postprandial state. Furthermore, the fact that more circulating glucose is used by muscle during exercise and early recovery suggests that muscle glycogen is spared.

To define the roles of beta- and alpha-adrenergic receptors in intense exercise, 17 lean healthy fit young males underwent 13.6 +/- 0.2 (+/-SE) min of cycle ergometer exercise: 6 at 100% maximum oxygen uptake (VO2max; MAX), 7 at their maximum possible (87 +/- 2.3%) during iv propranolol (P; 150 micrograms/kg bolus 30 min preexercise, then 80 micrograms/kg.min), and 7 (including 3 of the P subjects) at 87% VO2max (C) as controls for P. Plasma glucose increased from similar resting values to a peak in the early recovery period at 7.2 +/- 0.44 in MAX and 6.8 +/- 0.37 in P, but only 5.2 +/- 0.3 mmol/L in C. The rate of glucose appearance (Ra) rose about 8-fold in both MAX and P, but only 4-fold in C (P = 0.001). The rate of glucose disappearance (Rd) increased 4-fold in MAX, 5.5-fold in P, and 3-fold in C (P = 0.001). Plasma insulin declined during exercise (P < 0.05) in MAX and P, but not in C, whereas plasma glucagon increased modestly in all groups. The mean peak plasma norepinephrine level was 36.3 +/- 4.5 in MAX, 20.2 +/- 3.4 in P, and 15.2 +/- 2.9 nmol/L in C (P = 0.002); epinephrine reached 7141 +/- 1790 in MAX and 5605 +/- 1532 in P (P = NS), but only 1715 +/- 344 pmol/L in C (P = 0.03). Therefore, 1) an "unmasked" alpha-adrenergic effect, directly and/or via an altered glucagon/insulin ratio, probably contributed to increased Ra with P treatment; and 2) the marked facilitation of the increase in Rd with P supports a major role for beta-adrenergic restraint of Rd at this exercise intensity.

Summary: Introduction: Despite efforts to improve adherence to physical activity interventions in youth with obesity, low adherence and attrition remain areas of great concern. Objective: The study was designed to determine which physiological and/or psychological factors predicted low adherence in adolescents with obesity enrolled in a 6‐month exercise intervention study aimed to improve body composition. Methods: Three hundred four adolescents with obesity aged 14–18 years who volunteered for the HEARTY (Healthy Eating Aerobic and Resistance Training in Youth) randomized controlled trial completed physiological (body mass index, waist circumference, per cent body fat, resting metabolic rate and aerobic fitness) and psychological (body image, mood, self‐esteem and self‐efficacy) measures. Results: One hundred forty‐one out of 228 (62%) randomized to exercise groups had low adherence (completed <70% of the prescribed four exercise sessions per week) to the intervention protocol. Logistic regression revealed that there were no baseline demographic or physiological variables that predicted low adherence in the participants. Appearance concern (a subscale of body image) (odds ratio [OR] 1.46, 95% confidence interval [CI]: 1.01, 2.1, P = 0.04), depressive mood (OR 1.12, 95% CI: 1.01, 1.23, P = 0.03) and confused mood (OR 1.16, 95% CI: 1.05, 1.27, P = 0.003) (two subscales of mood) were significant predictors of low adherence. Conclusions: Adolescents with obesity who had higher appearance concerns and depressive and confused moods were less likely to adhere to exercise. Body image and mood should be screened to identify adolescents who may be at high risk of poor adherence and who may need concurrent or treatment support to address these psychological issues to derive maximal health benefits from an exercise programme. [ABSTRACT FROM AUTHOR]

Resistance training has been shown to increase strength in type 2 diabetes; however, it is unclear if combining resistance and aerobic training ( A + R) impedes strength development compared with resistance training only ( R). The purpose of this study was to compare changes in strength with A + R vs R in individuals with type 2 diabetes. We evaluated monthly workload increments in participants from the Diabetes Aerobic and Resistance Exercise clinical trial. Muscular strength was assessed through training volumes and as the eight repetition maximum (8- RM) at 0, 3, and 6 months. Both groups increased their upper and lower body volumes monthly for 6 months. The relative increase in upper body workload in R was significantly greater than A + R at 4 months (161 ± 11% vs 127 ± 11%, P = 0.009) and at 6 months of training (177 ± 11% vs 132 ± 11%, P = 0.008). Both groups had improvements in 8- RM workloads at 3 and 6 months. The resistance training group had a significantly greater improvement in 8- RM on the leg press at 6 months compared with A + R (80 ± 11% vs 58 ± 8%, P = 0.045). Both R and A + R improved strength with a 6-month training program; however, increases in strength may be greater with resistance training alone compared with performing both aerobic and resistance training. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Exercise training improves glycaemic control in some but not all individuals and little research has been done regarding genetic impact on the exercise training response in type 2 diabetes. The purpose of this study was to investigate the influence of the Pro12Ala variant of the peroxisome proliferator-activated receptor (PPAR) γ2 gene on changes in fasting plasma glucose in response to exercise training. Methods: The study population comprised 139 sedentary type 2 diabetic patients (age: 54.4±7.2; HbA1c: 7.7±0.9%) who completed 3 months of supervised exercise training. The primary outcome variable in our analysis was the post-intervention change in blood glucose. Other assessments included measures of body composition, insulin sensitivity indices and maximal oxygen uptake (VO2max). Results: The frequency of the Ala allele was 8.3% and the genotypes were in Hardy-Weinberg equilibrium. At baseline, neither body composition variables (weight, BMI, waist circumference), glucose homeostasis variables (glucose, insulin, HbA1c, homeostasis model assessment method) nor VO2max were different between genotypes (wild-type: Pro12Pro n=117, Ala carriers: X12Ala n=22). The exercise-training intervention led to similar improvements in body composition and glucose homeostasis variables in both genotype groups (p<0.05). The change in fasting plasma glucose was significantly different between PPARγ2 genotypes (-1.66 mmol/l vs -0.54 mmol/l, Ala carriers and wild-type, respectively) (p=0.034 unadjusted and p=0.089 including baseline glucose) and the significant association between genotype and glucose response remained after adjusting for statistically significant predictors (age, changes in insulin and BMI [p=0.015]) and including baseline glucose, insulin and BMI (p= 0.031). Conclusions/interpretation: These data suggest that the Pro12Ala polymorphism may influence the glycaemic response to exercise in type 2 diabetes. [ABSTRACT FROM AUTHOR]

JAMA 2001 Sept 12: 286(10): 1218–27 Context: Exercise is widely perceived to be beneficial for glycemic control and weight loss in patients with type 2 diabetes. However, clinical trials on the effects of exercise in patients with type 2 diabetes have had small sample sizes and conflicting results. Objective: To systematically review and quantify the effect of exercise on glycosylated hemoglobin (HbA(1c)) and body mass in patients with type 2 diabetes. Data sources: Database searches of MEDLINE, EMBASE, Sport Discuss, Health Star, Dissertation Abstracts and the Cochrane Controlled Trials Register for the period up to and including December 2000. Additional data sources included bibliographies of textbooks and articles identified by the database searches. Study selection: We selected studies that evaluated the effects of exercise interventions (duration ≥ = 8 weeks) in adults with type 2 diabetes. Fourteen (11 randomized and three non-randomized) controlled trials were included. Studies that included drug cointerventions were excluded. Data extraction: Two reviewers independently extracted baseline and post-intervention means and SDs for the intervention and control groups. The characteristics of the exercise interventions and the methodological quality of the trials were also extracted. Data synthesis: Twelve aerobic training studies [mean (SD), 3.4 (0.9) times/week for 18 (15) weeks] and two resistance training studies [mean (SD), 10 (0.7) exercises, 2.5 (0.7) sets, 13 (0.7) repetitions, 2.5 (0.4) times/week for 15 (10) weeks] were included in the analyses. The weighted mean post-intervention HbA(1c) was lower in the exercise groups compared with the control groups (7.65% vs 8.31%; weighted mean difference, 0.66%; P < 0.001). The difference in post-intervention body mass between exercise groups and control groups was not significant (83.02 kg vs 82.48 kg; weighted mean difference, 0.54; P= 0.76). Conclusion: Exercise training reduces HbA(1c) by an amount that should decrease the risk of diabetic complications, but no significantly greater change in body mass was found when exercise groups were compared with control groups. [ABSTRACT FROM AUTHOR]