Effect of Combined Exercise Training on Physical and Cognitive Function in Women With Type 2 Diabetes

OBJECTIVES

One of the consequences of old age is cognitive and physical decline, which can cause a wide range of problems. These complications are more pronounced in those with type 2 diabetes (T2D). The aim of this pilot study was to investigate the effect of combined exercise training on blood biomarkers, physical fitness, and cognitive function in elderly women with T2D.

METHODS

Twenty-one elderly women with T2D were randomly allocated to training (n=12) and control (n=9) groups. The exercise training program was a combination of aerobic, resistance, and balance exercises performed 3 times per week over 12 weeks. In the same period, the control group received no training intervention. Blood markers, including brain-derived neurotrophic factor (BDNF), irisin, glycated hemoglobin (A1C), fasting blood sugar (FBS), cardiorespiratory fitness (CRF), lower and upper body strength, and cognitive function, were measured in all participants at baseline and after 12 weeks.

RESULTS

Serum BDNF levels were not significantly different between the exercise and control groups at 12 weeks (p>0.05). FBS and A1C levels in the exercise group decreased significantly compared with the control group (p<0.05). CRF, dynamic balance, and both upper and lower body strength in the exercise group improved significantly compared with the control group (p<0.05). Irisin levels decreased significantly in the control group, but levels did not change significantly in the exercise group. Greater improvements from exercise were observed on the Montreal Cognitive Assessment index compared with the control group (p=0.05), but no other group differences in cognitive function were noted.

CONCLUSIONS

Combined exercise improved some physical fitness and diabetes-related surrogate factors, as well as select cognitive functions, but had no significant effect on cognition-related biochemical factors (i.e. BDNF) in women with T2D.

Body Satisfaction and Associated Predictors Among Baby Boomer Women in Rural and Urban Manitoba

Purpose: This study examines body satisfaction, weight attitudes, dieting behaviours, and aging concerns of baby boomer women (BBW; born 1946-1965) from rural and urban Manitoba.Methods: Primary data collection occurred November 2015, and 1083 participants completed the Body Image and Food Choice Survey. Four strata of BBW were represented to examine differences between older and younger BBW and location of residence. Multinomial logistic regression models were fit to determine predictors of weight and appearance satisfaction. Odds ratios and 95% confidence intervals were considered significant at p ≤ 0.05.Results: Fifty-three percent of participants were satisfied with their appearance, whereas only 34% were satisfied with their weight. Ninety-one percent desired to lose weight (29.9 ± 29.3 lbs). Aging anxiety was evident for 46% of participants and associated with appearance satisfaction (χ² = 27.46, df = 4, p < 0.001). Body work and dieting behaviours were used to mitigate body dissatisfaction, and media influence was associated with both appearance (χ² = 76.17, df = 6, p < 0.001) and weight satisfaction (χ² = 67.90, df = 6, p < 0.001). Desired weight change, appearance stress, appearance importance, and self-rated health predicted both weight and appearance satisfaction.Conclusions: There is a need for greater awareness of aging women's body image concerns and the need for age-appropriate tools/resources to help dietitians support women achieve a healthy body image.

[Physical Activity and Mental Health in the Elderly]

Physical Activity and Mental Health in the Elderly Abstract. The aging process is closely linked to physiological changes. These physiological changes may lead to an increased vulnerability for developing somatic and mental disorders. Reduced physical activity/sedentary behaviour can enhance this process. In contrast, physical training and sports counteract this process, in particular in the elderly, who may thus gain or maintain a younger biological age. Physical fitness is associated with better mental health in the elderly. Sports and physical activity over the course of life have shown to be of preventive value concerning the development of depression and dementia in old age. Also late-life depression and cognitive impairment (MCI, mild cognitive impairment) can be improved by regular, continuous physical exercise. Some data furthermore suggest that even patients with dementia benefit from physical exercise, especially on behalf of the behavioural and psychic symptoms of dementia (BPSD).

MEdical TReatment Optimization in cardiac rehabilitation (METRO study) : a French multicenter study

BACKGROUND

Cardiac rehabilitation (CR) is the right place to optimize the medical treatment in coronary artery disease (CAD) patients.

AIMS

To report the medical management in CAD patients during CR and evaluate the consequences.

METHODS

CAD patients who attended a CR program within less than three months of an acute coronary syndrome (ACS), a percutaneous coronary intervention (PCI), or a coronary artery bypass graft (CABG) were included in a prospective multicenter study. Medical treatments were analyzed at the beginning and at discharge of the CR stay. Results of exercise tests were compared between 4 groups. G1: unchanged medication, n=443, G2: beta-blockers or bradycardic agents adaptation n=199, G3: renin-angiotensin system (RAS) inhibitors adaptation, n=194, G4: both medications adaptation, n=164.

RESULTS

One thousand consecutive patients were included in 23 French CR centers (85.3% males; mean age 59.9 ± 11 years). The index event was ACS (68.5%), PCI (62.6%) and CABG (36.3%). During CR, we noted an adaptation for beta-blockers in 32.1%, in other bradycardic agents (ivabradine, verapamil, diltiazem, amiodarone) in 9.5%, and in RAS inhibitors in 36.3%. Patients of group 1 had an initial resting heart rate lower than in group 2 and 4, but at the final exercise testing, the range of the decrease was more important in group 2 and 4. The combination of physical training and therapeutic modifications resulted in similar exercise capacities in the four groups, from 5.2, 5.3, 5.4 and 5.2 MET (p=0.68), to 6.3, 6.5, 6.5 and 6.1 MET (p=0.44), respectively.

CONCLUSION

The METRO study showed that significant alteration in medical treatment during cardiac rehabilitation programs could take part in improving physical capacity.

Load-matched acute and chronic exercise induce changes in mitochondrial biogenesis and metabolic markers

We investigated the effects of acute and chronic exercise, prescribed in different intensity zones, but with total load-matched on mitochondrial markers (cytochrome C oxidase subunit IV (COX-IV), mitochondrial transcription factor A (Tfam), and citrate synthase (CS) activity in skeletal muscles, heart, and liver), glycogen stores, aerobic capacity, and anaerobic index in swimming rats. For this, 2 experimental designs were performed (acute and chronic efforts). Load-matched exercises were prescribed below, above, and on the anaerobic threshold (AnT), determined by the lactate minimum test. In chronic programs, 2 training prescription strategies were assessed (monotonous and linear periodized model). Results show changes in glycogen stores but no modification in the COX-IV and Tfam contents after acute exercises. In the chronic protocols, COX-IV and Tfam proteins and CS adaptations were intensity- and tissue-dependent. Monotonous training promoted better adaptations than the periodized model. Training at 80% of the AnT improved both performance variables, emphasizing the anaerobic index, concomitant to CS and COX-IV improvement (soleus muscle). The aerobic capacity and CS activity (gastrocnemius) were increased after 120% AnT training. In conclusion, acute exercise protocol did not promote responses in mitochondrial target proteins. An intensity and tissue dependence were reported in the chronic protocols, highlighting training at 80 and 120% of the AnT. Novelty: Load-matched acute exercise did not enhance COX-IV and Tfam contents in skeletal muscles, heart, and liver. In chronic exercise, COX-IV, Tfam, and CS activity adaptations were intensity- and tissue-dependent. Monotonous training was more efficient than the periodized linear model in adaptations of target proteins and enzymatic activity.

Assessing the utility of cardiorespiratory fitness, visceral fat, and liver fat in predicting changes in insulin sensitivity beyond simple changes in body weight after exercise training in adolescents

To examine the utility of changes in cardiorespiratory fitness (CRF) and body composition in response to exercise training in adolescents with obesity beyond simple measures of body weight change. This is a secondary analysis of our previously published randomized trials of aerobic, resistance, and combined training. We included 104 adolescents (body mass index (BMI) ≥85th percentile) who had complete baseline and post-intervention data for CRF, regional body fat, insulin sensitivity, and oral glucose tolerance. Associations between changes in body composition and CRF with cardiometabolic variables were examined adjusted for age, sex, Tanner stage, race, exercise group, and weight loss. At baseline, CRF, visceral fat and liver fat were correlated with insulin sensitivity with and without adjustment for BMI percentile. Training-associated changes in CRF, visceral fat, and liver fat were also correlated with insulin sensitivity changes, but not independent of body weight change. After accounting for body weight change, none of the body composition or CRF were associated with changes in insulin sensitivity, glucose tolerance, systolic blood pressure, or high-density lipoprotein cholesterol. Although CRF and body composition were strong independent correlates of insulin sensitivity at baseline, changes in CRF and visceral fat were not associated with changes in insulin sensitivity after accounting for body weight change. Clinicaltrials.gov registration nos.: NCT00739180, NCT01323088, NCT01938950. Novelty With exercise training, changes in body weight, CRF, visceral fat, and liver fat were correlated with changes in insulin sensitivity. Changes in body composition or CRF generally did not remain significant correlates of changes in insulin sensitivity after adjusting for body weight changes.

Dietary restriction and/or exercise training impairs spermatogenesis in normal rats

Dietary restriction and/or exercise has been shown to have multiple benefits for health. However, its effects on reproductive health and the mechanisms by which it regulates reproductive function remain unclear. Here, to evaluate its effects on spermatogenesis and sperm function, rats were divided into 4 groups: ad libitum-fed sedentary control, dietary restriction (DR), exercise training (ET), and dietary restriction plus exercise training (DR+ET) groups. Results indicated that body weight, epididymal fat pad weight, and sperm counts were significantly reduced in the DR, ET, and DR+ET groups. Moreover, sperm motility and capacitation-associated protein tyrosine phosphorylation were suppressed in the DR and DR+ET groups, but not the ET group. Microarray analysis revealed that the number of downregulated genes was higher than that of upregulated genes in the DR and/or ET groups. About half of the downregulated genes are common after exercise training and/or diet restriction. Gene ontology analysis showed that downregulated genes in the DR, ET, and DR+ET groups affected spermatogenesis through overlapping pathways, including glucocorticoid, corticosteroid, extracellular structure organization, and estradiol responses. Our findings suggest that diet restriction and/or exercise training may present potential risks to male reproductive dysfunction by disrupting normal gene expression patterns in the testis. Novelty: Dietary restriction and/or exercise can lead to the damage of spermatogenesis as well as sperm maturation. Sperm functional changes are more sensitive to dietary restriction than exercise training. Dietary restriction and exercise impair spermatogenesis through overlapping biological pathways in the testis.

Combined effects of exercise training and high doses of anabolic steroids on cardiac autonomic modulation and ventricular repolarization properties in rats

Several studies have reported that high doses of synthetic anabolic androgenic steroids (AAS) can have serious negative effects on health, including the cardiovascular system. The aim of this study was to evaluate the combined effects of AAS and exercise training on ventricular repolarization and cardiac autonomic modulation in rats. Male Wistar rats were allocated into 4 groups: sedentary rats treated with vehicle, sedentary rats treated with nandrolone decanoate, swimming-trained rats treated with vehicle, and swimming-trained rats treated with nandrolone decanoate. Ventricular repolarization was evaluated by electrocardiographic analysis of QT interval and QT dispersion. Cardiac autonomic modulation was assessed by heart rate variability. Our results show that AAS increased QT interval and QT dispersion in sedentary rats treated with nandrolone decanoate as compared to sedentary rats treated with vehicle, indicating AAS-induced ventricular repolarization abnormalities. When rats treated with nandrolone decanoate were subjected to concomitant exercise training, ventricular repolarization was normalized. On the other hand, AAS-induced reduction in cardiac parasympathetic modulation was not prevented by exercise training. In conclusion, AAS produced cardiac autonomic dysfunction and ventricular repolarization disturbances in rats. Combining an exercise training protocol during the AAS treatment attenuated the ventricular repolarization abnormalities and did not prevent cardiac autonomic dysfunction.

Higher baseline fat oxidation promotes gynoid fat mobilization in response to a 12-week exercise intervention in sedentary, obese black South African women

This 12-week exercise intervention study assessed changes in cardiorespiratory fitness (CRF), energy expenditure (EE), and substrate utilisation at rest and during exercise in obese, black South African (SA) women and explored associations with changes in body composition. Black SA women (body mass index: 30-40 kg·m^-2, age: 20-35 years) were randomised into control (CTL; n = 15, maintaining usual activity) or exercise (EXE; n = 20; 12 weeks, 4 days·week^-1, 40-60 min·day^-1 at >70% peak heart rate) groups. Pre- and post-intervention testing included peak oxygen consumption, resting and steady state (50% peak oxygen consumption) EE, respiratory exchange, and body composition (dual-energy X-ray absorptiometry). Dietary intake (4-day) and daily step-count (ActivPAL, activPAL3c; PAL Technologies Ltd, Glasgow, UK) was collected at pre-testing and at 4, 8, and 12 weeks. EXE increased peak oxygen consumption (24.9 ± 2.4 to 27.6 ± 3.4 mL·min^-1·kg^-1; p < 0.001) and steady state fat oxidation rates (7.5 ± 2.5 to 9.0 ± 2.7 mg·min^-1·kg^-1 fat-free soft tissue mass; p = 0.003) (same relative exercise intensity). CTL remained unchanged (p > 0.05). EXE reduced proportional gynoid fat mass (percentage total fat mass, p = 0.002). Baseline resting carbohydrate oxidation rates (p = 0.036) and steady state fat oxidation rates (p = 0.021) explained 60.6% of the variability in Δgynoid fat mass (p < 0.001) in EXE. This 12-week exercise intervention improved CRF and steady state fat oxidation rates. Greater reliance on fat oxidation at baseline promoted proportional reductions in gynoid, not visceral, fat mass in response to exercise training. Novelty Combined exercise training in obese black South African women increased cardiorespiratory fitness and rates of fat oxidation during steady state exercise. Exercise training reduced proportional gynoid, not visceral, fat, potentially representing an ethnic/sex-specific response. Baseline substrate utilisation (resting and steady state exercise (50% peak oxygen uptake)) predicted changes in gynoid fat mass.

Is active recovery during cold water immersion better than active or passive recovery in thermoneutral water for postrecovery high-intensity sprint interval performance?

High-intensity exercise is impaired by increased esophageal temperature (T_es) above 38 °C and/or decreased muscle temperature. We compared the effects of three 30-min recovery strategies following a first set of three 30-s Wingate tests (set 1), on a similar postrecovery set of Wingate tests (set 2). Recovery conditions were passive recovery in thermoneutral (34 °C) water (Passive-TN) and active recovery (underwater cycling; ∼33% maximum power) in thermoneutral (Active-TN) or cold (15 °C) water (Active-C). T_es rose for all conditions by the end of set 1 (∼1.0 °C). After recovery, T_es returned to baseline in both Active-C and Passive-TN but remained elevated in Active-TN (p < 0.05). At the end of set 2, T_es was lower in Active-C (37.2 °C) than both Passive-TN (38.1 °C) and Active-TN (38.8 °C) (p < 0.05). From set 1 to 2 mean power did not change with Passive-TN (+0.2%), increased with Active-TN (+2.4%; p < 0.05), and decreased with Active-C (-3.2%; p < 0.05). Heart rate was similar between conditions throughout, except at end-recovery; it was lower in Passive-TN (92 beats·min^-1) than both exercise conditions (Active-TN, 126 beats·min^-1; Active-C, 116 beats·min^-1) (p < 0.05). Although Active-C significantly reduced T_es, the best postrecovery performance occurred with Active-TN. Novelty An initial set of 3 Wingates increased T_es to ∼38 °C. Thirty minutes of Active-C was well tolerated, and decreased T_es and blood lactate to baseline values, but decreased subsequent Wingate performance.

The impact of high-intensity interval training and moderate-intensity continuous training regimes on cardiodynamic parameters in isolated heart of normotensive and hypertensive rats

This study aimed to assess the impact of high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MIT) on cardiodynamic parameters in isolated rat heart. Wistar albino rats were randomly assigned to groups according to running protocol: sedentary control, MIT, and HIIT; spontaneous hypertensive rat (SHR) sedentary control, SHR + MIT, and SHR + HIIT. HIIT groups performed the running in 5 sprints × 45-55 m/min for 30-90 s, with 2 min of rest after each sprint, while MIT groups performed the running of 10-15 m/min for 1 h with 3 min of rest every 100 m; both protocols were implemented 5 days/week over 4 weeks with 1 week of adaptation before protocols started. Isolated rat hearts were perfused according to Langendorff technique at gradually increased coronary perfusion pressures (40-120 cmH₂O). Using a sensor placed in the left ventricle, we registered maximum and minimum rate of pressure development in the left ventricle, systolic and diastolic left ventricular pressure, and heart rate. Coronary flow was measured flowmetrically. MIT was connected with cardiac depression in normotensive conditions, while HIIT leads to cardiac depression in hypertensive rats. HIIT induced more significant increase of contractile and relaxation parameters of the isolated rat heart, especially in hypertensive animals.

High-fat diet leads to adiposity and adipose tissue inflammation: the effect of whey protein supplementation and aerobic exercise training

There is little understanding about dietary proteins and their potential contribution to obesity-induced inflammation. This study investigates the effect of 10 weeks of aerobic training and whey protein (WP) supplementation on visceral adipose tissue inflammation in rats fed a high-fat diet (HFD). In the first phase, which lasted 9 weeks, 40 male Wistar rats were randomly divided into 2 groups: (1) normal diet (n = 8), and (2) HFD (n = 32). In the second phase, rats fed an HFD were randomly assigned into 4 groups (n = 8/group): (1) sedentary, (2) WP, (3) aerobic training, and (4) WP + aerobic training. The aerobic training was performed for 10 weeks, 5 days/week at 21 m/min, 15% incline, for 60 min/day. HFD significantly increased body weight, adiposity index, fat pads weight, glucose levels, and insulin resistance index compared with the normal diet. Also, levels of tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), hypoxia inducible factor 1 alpha (HIF-1α), and vascular endothelial growth factor A (VEGF-A) in adipose tissue and serum levels of TNF-α were increased in the HFD group. Glucose levels, insulin resistance index, and triglycerides were reduced only by WP, independently of aerobic training. Both the aerobic training and WP reduced the fat pads weight and levels of TNF-α, HIF-1α, and VEGF-A in adipose tissue. Nevertheless, the levels of MCP-1 in adipose tissue and serum levels of TNF-α and MCP-1 were not reduced significantly by WP or aerobic training. These findings suggest that both aerobic training and WP supplementation lead to a reduction in adiposity and ameliorate obesity-induced inflammation in visceral adipose tissue.

Does blood lactate predict the chronic adaptive response to training: A comparison of traditional and talk test prescription methods

The purpose of this study was to test the hypotheses (i) that interindividual variability in acute blood lactate responses during exercise at 65% of peak work rate (WR_peak; relative WR_peak protocol (REL)) will predict variability in the chronic responses to exercise training and (ii) that exercising at an intensity that causes uncomfortable speech production (negative talk test (TT) stage (NEG)) elicits high acute blood lactate responses and large adaptations to training. Twenty-eight participants completed 4 weeks of exercise training consisting of REL (n = 14) or NEG (TT, n = 14). Fifteen additional participants were assigned to a no-exercise control group (n = 15). In REL, acute blood lactate responses during the first training session significantly predicted changes in peak oxygen consumption (r = 0.69) after training. TT resulted in consistently high acute blood lactate responses. REL and TT improved (p < 0.05) peak oxygen consumption, WR_peak, and work rate at the onset of blood lactate accumulation (WR_OBLA). Despite nonsignificance, small to medium between-group effect sizes for changes in peak oxygen consumption, WR_peak, and WR_OBLA and a higher work rate, heart rate, rating of perceived exertion, and blood lactate during training at NEG support the potential superiority of TT over REL. When exercise is prescribed using a traditional method (a fixed percentage of WR_peak; REL), acute metabolic stress may partly explain the variance in the adaptations to training. In addition, TT elicited significant increases in peak oxygen consumption, WR_peak, and WR_OBLA, and although our small sample size limits our ability to confidently compare training adaptations between groups, our preliminary results suggest that future investigations with larger sample sizes should assess the potential superiority of TT over REL.

Effect of 7 days of exercise on exogenous carbohydrate oxidation and insulin resistance in children with obesity

The capacity to match carbohydrate (CHO) oxidation with CHO availability (deemed metabolic flexibility (MetFlex)) may be important for type 2 diabetes prevention. In adults, impaired MetFlex is associated with insulin resistance (IR), which can be improved with as little as 7 days of exercise. Whether this occurs similarly in children is unknown. We hypothesized that 7 consecutive days of exercise would improve MetFlex and IR in children with obesity. Twelve children (8 boys, 4 girls) completed 2 study visits before (PRE) and 2 study visits after (POST) exercise training. At visit 1, fasting blood was collected, and anthropometry and maximal oxygen uptake were assessed. At visit 2, a ¹³C-enriched CHO drink was ingested before exercise (3 × 20 min) at ∼59% maximal oxygen uptake. Exogenous CHO oxidative efficiency, used as a surrogate measurement of MetFlex, was calculated from breath samples. During training, participants alternated between continuous and high-intensity interval cycling sessions at home under supervision. In spite of good training adherence, there was no improvement in MetFlex (PRE: 20.7% ± 1.8%, POST: 18.9% ± 4.9%, p = 0.22) or homeostasis model assessment of insulin resistance (PRE: 8.7 ± 4.6, POST: 8.1 ± 6.0, p = 0.51). Future research should investigate exercise volume, sex, and pubertal effects on the early responsiveness of MetFlex to exercise therapy.

Association between aerobic exercise training effects of serum adropin level, arterial stiffness, and adiposity in obese elderly adults

Serum levels of adropin, which enhances endothelial cell release of nitric oxide (NO), are lower in obese patients. Although habitual aerobic exercise reduces arterial stiffness and adiposity, the relationship between these effects and circulating levels of adropin remains unclear. The purpose of this study was to determine if serum adropin level is associated with the effects of aerobic exercise training on arterial stiffness and adiposity in obese adults. In Experiment 1, we examined whether serum adropin levels are associated with cardiorespiratory fitness, carotid β-stiffness, plasma nitrite/nitrate (NOx) level, and abdominal visceral fat in 27 normal, 20 overweight, and 25 obese adults (age, 41-79 years). In Experiment 2, we examined the effects of an 8-week aerobic exercise training program on the relationship between serum adropin level and arterial stiffness or adiposity in 13 obese adults (age, 54-76 years). Serum adropin levels in normal, overweight, and obese adults negatively correlated with carotid β-stiffness and abdominal visceral fat, and positively correlated with plasma NOx level and cardiorespiratory fitness. After the 8-week exercise program, serum adropin levels in obese adults were elevated, and correlated with training-induced changes in carotid β-stiffness (r = -0.573, P < 0.05), plasma NOx level (r = 0.671, P < 0.05), and abdominal visceral fat (r = -0.585, P < 0.05). These findings suggest that the exercise training-induced increase in serum adropin may be related to the training effects of arterial stiffness and adiposity in obese adults.

Exercise training attenuates the pressor response evoked by peripheral chemoreflex in rats with heart failure

The effects of exercise training (ExT) on the pressor response elicited by potassium cyanide (KCN) in the rat model of ischemia-induced heart failure (HF) are unknown. We evaluated the effects of ExT on chemoreflex sensitivity and its interaction with baroreflex in rats with HF. Wistar rats were divided into four groups: trained HF (Tr-HF), sedentary HF (Sed-HF), trained sham (Tr-Sham), and sedentary sham (Sed-Sham). Trained animals underwent to a treadmill running protocol for 8 weeks (60 m/day, 5 days/week, 16 m/min). After ExT, arterial pressure (AP), baroreflex sensitivity (BRS), peripheral chemoreflex (KCN: 100 μg/kg body mass), and cardiac function were evaluated. The results demonstrate that ExT induces an improvement in BRS and attenuates the pressor response to KCN relative to the Sed-HF group (P < 0.05). The improvement in BRS was associated with a reduction in the pressor response following ExT in HF rats (P < 0.05). Moreover, ExT induced a reduction in left ventricular end-diastolic pressure and pulmonary congestion compared with the Sed-HF group (P < 0.05). The pressor response to KCN in the hypotensive state is decreased in sedentary HF rats. These results suggest that ExT improves cardiac function and BRS and attenuates the pressor response evoked by KCN in HF rats.

Nandrolone decanoate negatively reverses the beneficial effects of exercise on cardiac muscle via sarcolemmal, but not mitochondrial K(ATP) channel

ATP-sensitive potassium channels are supposed to have a substantial role in improvement of cardiac performance. This study was performed to evaluate whether nandrolone decanoate (ND) and (or) exercise training could affect the expression of cardiac K(ATP) channel subunits. Thirty-five male albino Wistar rats were randomly divided into 5 groups, including sedentary control (SC), sedentary vehicle (SV), sedentary ND (SND), exercise control (EC), and exercise and ND (E+ND). Exercise training was performed on a treadmill 5 times per week. ND was injected (10 mg/kg/week, i.m.) to the rats in the SND and E+ND groups. Following cardiac isolation, the expression of both sarcolemmal and mitochondrial subunits of K(ATP) channel was measured using Western blot method. The expression of sarcolemmal, but not mitochondrial, subunits of K(ATP) channel (Kir6.2 and SUR2) of EC group was significantly higher compared with SC group while ND administration (SND group) did not show any change in their expression. In the E+ND group, ND administration led to decrease of the over-expression of sarcolemmal Kir6.2 and SUR2 which was previously induced by exercise. There was no significant association between the mitochondrial expression of either Kir6.2 or SUR2 proteins and administration of ND or exercise. Supra-physiological dosage of ND negatively reverses the effects of exercise on the cardiac muscle expression of sarcolemmal, but not mitochondrial, K(ATP) channel subunits.

Influence of exercise training with resveratrol supplementation on skeletal muscle mitochondrial capacity

Physical inactivity reduces, and exercise training increases, mitochondrial capacity. In rodents, exercise training effects can be augmented by large doses of resveratrol supplementation but whether this can occur in humans with a smaller dose is unclear. This study sought to determine the effects of resveratrol supplementation in combination with exercise training on skeletal muscle mitochondrial capacity. Sixteen healthy young adults were randomly assigned in a double-blind fashion to consume either placebo or 500 mg of resveratrol plus 10 mg of piperine, a bioenhancer to increase bioavailibilty and bioefficacy of resveratrol. Participants ingested the pills daily for 4 weeks and completed 3 sessions per week of submaximal endurance training of the wrist flexor muscles of the nondominant arm. The contralateral arm served as an untrained control. Skeletal muscle mitochondrial capacity was measured using near-infrared spectroscopy. Changes in mitochondrial capacity from baseline to post-testing indicated significant differences between the resveratrol+piperine-trained arm and the placebo-trained arm (p = 0.02), with the resveratrol+piperine group increasing about 40% from baseline (Δk = 0.58), while the placebo group increased about 10% from baseline (Δk = 0.13). Neither the placebo group nor the resveratrol+piperine group exhibited changes in mitochondrial capacity in the untrained arm. In conclusion, low-intensity exercise training can increase forearm skeletal muscle mitochondrial capacity when combined with resveratrol and piperine supplementation.

Effect of 1-h moderate-intensity aerobic exercise on intramyocellular lipids in obese men before and after a lifestyle intervention

Intramyocellular lipids (IMCL) are depleted in response to an acute bout of exercise in lean endurance-trained individuals; however, it is unclear whether changes in IMCL content are also seen in response to acute and chronic exercise in obese individuals. We used magnetic resonance spectroscopy in 18 obese men and 5 normal-weight controls to assess IMCL content before and after an hour of cycling at the intensity corresponding with each participant's maximal whole-body rate of fat oxidation (Fatmax). Fatmax was determined via indirect calorimetry during a graded exercise test on a cycle ergometer. The same outcome measures were reassessed in the obese group after a 16-week lifestyle intervention comprising dietary calorie restriction and exercise training. At baseline, IMCL content decreased in response to 1 h of cycling at Fatmax in controls (2.8 ± 0.4 to 2.0 ± 0.3 A.U., -39%, p = 0.02), but not in obese (5.4 ± 2.1 vs. 5.2 ± 2.2 A.U., p = 0.42). The lifestyle intervention lead to weight loss (-10.0 ± 5.4 kg, p < 0.001), improvements in maximal aerobic power (+5.2 ± 3.4 mL/(kg·min)), maximal fat oxidation rate (+0.19 ± 0.22 g/min), and a 29% decrease in homeostasis model assessment score (all p < 0.05). However, when the 1 h of cycling at Fatmax was repeated after the lifestyle intervention, there remained no observable change in IMCL (4.6 ± 1.8 vs. 4.6 ± 1.9 A.U., p = 0.92). In summary, there was no IMCL depletion in response to 1 h of cycling at moderate intensity either before or after the lifestyle intervention in obese men. An effective lifestyle intervention including moderate-intensity exercise training did not impact rate of utilisation of IMCL during acute exercise in obese men.

Muscle sympathetic activity in resting and exercising humans with and without heart failure

The sympathetic nervous system is critical for coordinating the cardiovascular response to various types of physical exercise. In a number of disease states, including human heart failure with reduced ejection fraction (HFrEF), this regulation can be disturbed and adversely affect outcome. The purpose of this review is to describe sympathetic activity at rest and during exercise in both healthy humans and those with HFrEF and outline factors, which influence these responses. We focus predominately on studies that report direct measurements of efferent sympathetic nerve traffic to skeletal muscle (muscle sympathetic nerve activity; MSNA) using intraneural microneurographic recordings. Differences in MSNA discharge between subjects with and without HFrEF both at rest and during exercise and the influence of exercise training on the sympathetic response to exercise will be discussed. In contrast to healthy controls, MSNA increases during mild to moderate dynamic exercise in the presence of HFrEF. This increase may contribute to the exercise intolerance characteristic of HFrEF by limiting muscle blood flow and may be attenuated by exercise training. Future investigations are needed to clarify the neural afferent mechanisms that contribute to efferent sympathetic activation at rest and during exercise in HFrEF.

Role of O-GlcNAcylation in nutritional sensing, insulin resistance and in mediating the benefits of exercise

The purpose of this review is to highlight the role of O-linked β-N-acetylglucosamine (O-GlcNAc) protein modification in metabolic disease states and to summarize current knowledge of how exercise affects this important post-translational signalling pathway. O-GlcNAc modification is an intracellular tool capable of integrating energy supply with demand. The accumulation of excess energy associated with obesity and insulin resistance is mediated, in part, by the hexosamine biosynthetic pathway (HBP), which results in the O-GlcNAcylation of a myriad of proteins, thereby affecting their respective function, stability, and localization. Insulin resistance is related to the excessive O-GlcNAcylation of key metabolic proteins causing a chronic blunting of insulin signalling pathways and precipitating the accompanying pathologies, such as heart and kidney disease. Lifestyle modifications such as diet and exercise also modify the pathway. Exercise is a front-line and cost-effective therapeutic approach for insulin resistance, and recent work shows that the intervention can alter O-GlcNAc gene expression, signalling, and protein modification. However, there is currently no consensus on the effect of frequency, intensity, type, and duration of exercise on O-GlcNAc modification, the HBP, and its related enzymes. On one end of the spectrum, mild, prolonged swim training reduces O-GlcNAcylation, while on the other end, higher intensity treadmill running increases cardiac protein O-GlcNAc modification. Clearly, a balance between acute and chronic stress of exercise is needed to reap the benefits of the intervention on O-GlcNAc signalling.

Acute exercise ameliorates differences in insulin resistance between physically active and sedentary overweight adults

Although regular exercise is associated with reduced cardiometabolic disease risk among overweight adults, it remains unclear whether much of the health benefits of exercise are derived from the most recent session(s) of exercise or if they are the result of adaptations stemming from weeks, months, or even years of training. The purpose of this study was to compare the effects of habitual and acute exercise on key markers of cardiometabolic disease risk in overweight adults. We compared insulin sensitivity index (ISI) using an oral glucose tolerance test, blood pressure (BP), blood lipids, and systemic inflammatory cytokines in 12 overweight to mildly obese adults (BMI: 27-34 kg/m(2)) who exercise regularly (EX; >2.5 h exercise per week) with a well-matched cohort of 12 nonexercisers (Non-EX). Baseline measurements in EX were performed exactly 3 days after exercise, whereas Non-EX remained sedentary. We repeated these measurements the day after a session of exercise in both groups. At baseline, ISI was significantly greater in EX versus Non-EX (3.1 ± 0.2 vs. 2.3 ± 0.2; p = 0.02), but BP, blood lipids, and plasma concentration of the systemic inflammatory cytokines we measured were not different between groups. Acute exercise increased ISI the next morning in Non-EX (2.3 ± 0.2 vs. 2.8 ± 0.3; p = 0.03) but not EX. As a result, ISI was similar between groups the morning after exercise. In summary, exercising regularly was accompanied by a persistent improvement in insulin sensitivity that lasted at least 3 days after exercise in overweight adults, but just one session of exercise increased insulin sensitivity among sedentary overweight adults to levels equivalent to the regular exercisers.