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Effect of chronic ethanol ingestion and exercise training on skeletal muscle in rat.

The aim of this study was to investigate the interactive effects of exercise training and chronic ethanol consumption on metabolism, capillarity, and myofibrillar composition in rat limb muscles. Male Wistar rats were treated in separate groups as follows: non exercised-control; ethanol (15%) in animals' drinking water for 12 weeks; exercise training in treadmill and ethanol administration plus exercise for 12 weeks. Ethanol administration decreased capillarity and increased piruvate kinase and lactate dehydrogenase activities in white gastrocnemius; in plantaris muscle, ethanol increased citrate synthase activity and decreased cross-sectional area of type I, IIa, and IIb fibres. Exercise increased capillarity in all four limb muscles and decreased type I fibre area in plantaris. The decreased capillarity effect induced by ethanol in some muscles, was ameliorated when alcohol was combined with exercise. While alcoholic myopathy affects predominantly type IIb fibres, ethanol administration and aerobic exercise in some cases can affect type I and type IIa fibre areas. The exercise can decrease some harmful effects produced by ethanol in the muscle, including the decrease in the fibre area and capillary density.

Analysis of Variance↗

Changes in tumor necrosis factor-alpha system and insulin sensitivity during an exercise training program in obese women with normal and impaired glucose tolerance.

OBJECTIVE: Tumor necrosis factor-alpha (TNFalpha) plays an important role in the pathogenesis of insulin resistance and type 2 diabetes. Plasma levels of the soluble (s) fractions of TNFalpha receptors, especially sTNFR2, are good indicators of TNFalpha system activation in obesity. The aim of the present study was to assess the effect of exercise training on the TNFalpha system and to evaluate the relationship with changes in insulin sensitivity. DESIGN AND METHODS: Sixteen obese women (body mass index (BMI)>27.8 kg/m(2)), 8 with normal (NGT) and 8 with impaired glucose tolerance (IGT), participated in an exercise training program which lasted for 12 weeks and included exercise performed on a bicycle ergometer at an individual intensity of 70% maximal heart rate, for 30 min, 5 days a week. Anthropometrical measurements and blood biochemical analyses were performed, and plasma TNFalpha, sTNFR1 and sTNFR2 levels were assessed. Insulin sensitivity was evaluated using the hyperinsulinemic euglycemic clamp technique (insulin infusion: 50 mU x kg(-1)xh(-1)). RESULTS: At baseline, despite similar anthropometrical parameters, IGT subjects were markedly more insulin resistant and had higher TNFalpha and sTNFR2 concentrations. Exercise training increased insulin sensitivity and decreased TNFalpha and sTNFR2 levels, while sTNFR1 remained unchanged. The decrease in sTNFR2 was significantly related to the increase in insulin sensitivity; that relationship remained significant after adjustment for the concurrent changes in BMI, waist circumference, percentage of body fat, plasma glucose, insulin and free fatty acids. CONCLUSIONS: Regular physical exercise decreases TNFalpha system activity and that decrease may be responsible for the concurrent increase in insulin sensitivity.

Adult↗

Exercise training reverses the age-related decline in tyrosine hydroxylase expression in rat hypothalamus.

Tyrosine hydroxylase (TH) is the rate-limiting enzymatic step in the catecholamine biosynthesis pathway. Some studies have demonstrated that aging is associated with a decrease in TH activity and TH mRNA in rat hypothalamus. We previously demonstrated that exercise training can decrease TH gene expression in the adrenal medulla of young but not senescent rats. This study was designed to examine the effects of endurance training on the TH expression in hypothalamus with aging. To this end, we assessed TH mRNA, TH immunoreactivity, and TH activity with or without exercise training. Young and old F-344 female rats were trained by treadmill running for 8 weeks. All parameters examined were significantly lower in hypothalamus of old (25-month) compared with young (5-month) control animals (p < .05). Exercise training significantly elevated TH mRNA (n = 5-7 in each group), TH immunoreactivity (n = 5-8 in each group), and TH activity (n = 12-13 young groups and n = 6 old groups) in the hypothalamus of old animals (p < .05), but there was no significant change in any of these parameters in young animals following training. These data indicate that endurance training can reverse the age-related decline in catecholamine biosynthesis in the hypothalamus.

Aging↗

Efficacy of high-intensity exercise training on left ventricular ejection fraction in men with coronary artery disease (the Training Level Comparison Study).

The purpose of this study was to compare high- versus low-intensity exercise training on the change in echocardiographic left ventricular ejection fraction (LVEF) from rest to peak exercise. Sedentary men with coronary artery disease, aged 30 to 70 years, were randomized to dynamic exercise training of either low intensity, 50% of maximal oxygen consumption, n = 89; or high intensity, 85% of maximal oxygen consumption, n = 111. No other interventions were imposed and patients were evaluated at 6 months and 1 year. Both exercise groups significantly increased exercise capacity without adverse events, but the increase was greater (p = 0.02) in the high-intensity exercise group. The mean exercise test rest-peak LVEF in the high-intensity group rose from 6.20% at baseline to 6.54% in 6 months and to 6.73% at 12 months, while the low-intensity group showed no improvement at 6 months and a decrease at 12 months. Multivariate analyses revealed that treatment group (high versus low intensity) significantly contributed to the change in rest-peak LVEF. When the exercise groups were subdivided by initial baseline LVEF < or = 50% versus > 50%, those with the higher LVEF in the high-intensity group showed a greater (p = 0.05) increase in the rest-peak LVEF from baseline to 1 year. Over a 1-year period, exercise capacity improved in both exercise-intensity groups, but more so in the high-intensity group, with no adverse events. The high-intensity group, compared with the low-intensity, showed more improvement in the rest-peak LVEF, especially in those with a higher LVEF at baseline.

Adult↗

[Exercise training of lower limbs in pulmonary rehabilitation of COPD patients].

Pulmonary rehabilitation is an efficient treatment method of COPD patients, recommended by GOLD programme, beginning with stage II. We followed the role of exercise training of lower limbs in improving exercise capacity and quality of life in medium and severe forms of COPD. Depending on COPD stadium, patients were included in an endurance or interval programme. We performed six-minute walking test and a QOL test before and after the programme. We observed a significant improvement of distance covered in six-minute walking test and of quality of life in these patients. Exercise training elicits important clinic benefits: improves exercise performance, quality of life and relieves symptoms in COPD.

Exercise Therapy↗

The effect of exercise training on physical fitness and plasma lipids in young Chinese men and women.

BACKGROUND: The mortality from coronary heart disease (CHD) has been steadily increasing in many parts of the world. Measures to reduce the incidence of CHD were initially addressed mainly to middle aged and elderly population groups, but for effective prevention of CHD, measures addressed to younger age groups are also necessary. Moreover, differences between male and female plasma lipid changes after exercise training are not known exactly. METHODS: The concentrations of plasma lipids, before and after regular physical exercise training for 12 weeks, were analyzed in 25 male and 25 female medical students of the same age group. Physical fitness was evaluated by the measurement of maximum oxygen uptake. RESULTS: Results indicated that plasma tri-glyceride, HDL-cholesterol, LDL-cholesterol and VLDL-cholesterol differences between the before-and-after exercise were significant (p < 0.05) in males while the differences of plasma total cholesterol were found to be insignificant. In females there were no significant changes in the plasma lipids levels. In both males and females, the marked increase in maximal O2 uptake after exercise training indicated an improvement in physical fitness. CONCLUSIONS: This study concludes that a short-term exercise program can improve plasma lipid and lipoprotein patterns more in males than in females. It also suggests that daily physical exercise may be an important prevention for cardiovascular diseases in later life, so it is essential to establish a life style with optimum nutrition and physical activity in both the young and in adults of all ages.

Adult↗

Possible role of nitric oxide on adipocyte lipolysis in exercise-trained rats.

A possible role of nitric oxide (NO) on adipocyte lipolysis was studied in exercise-trained (9 weeks of running) rats. Lipolysis in adipose tissue tended to be greater in trained rats than in control rats. A treatment of adipose tissue with 5 mM N(G)-nitro-L-arginine methyl ester (L-NAME) showed that basal and isoproterenol-stimulated lipolysis were both significantly greater in trained rats than in control rats. In contrast, in isolated adipocytes L-NAME had no effect on lipolysis in either group of rats, though the lipolysis of isolated adipocytes was significantly greater in trained rats than in control rats. Training significantly reduced nitrite/nitrate production in adipocytes, but not in tissue. On the other hand, training increased the protein expression of endothelial nitric oxide synthase (eNOS), but not that of inducible NOS (iNOS) in the extracts of tissue homogenates. In tissue homogenates, eNOS activity but not iNOS activity was significantly greater in trained rats than in control rats. In cellular extracts, training significantly reduced the activities of both NOS's, but the mRNA expressions of both NOS's were not different between groups. The NO donors, S-nitroso-N-acetyl-penicillamine (SNAP) and 1-propamine, 3-(2-hydroxy-2-nitroso-1-propyl-hydrazine) (PAPA-NONOate), significantly inhibited adipocyte lipolysis in response to isoproterenol in both groups. This inhibitory effect of SNAP, but not that of PAPA-NONOate, was greater in the adipocytes of trained rats than in those of the control rats. Thus it is possible that NO is involved in the regulation of lipolysis and that exercise training enhances the responsiveness of adipocytes to extracellular NO with the reduced production of nitrite/nitrate in adipocytes because of decreased activities of NOS's. On the other hand, it is also possible that exercise increases either the activity or the protein expression of eNOS in adipose tissue.

Adipocytes↗

Exercise training increases myocardial inotropic response in food restricted rats.

This study evaluated the effects of exercise training on myocardial function and ultrastructure of rats submitted to different levels of food restriction (FR). Male Wistar-Kyoto rats, 60 days old, were submitted to free access to food, light FR (20%), severe FR (50%) and/or to swimming training (one hour per day with 5% of load, five days per week for 90 days). Myocardial function was evaluated by left ventricular papillary muscle under basal condition (calcium 1.25 mM), and after extracellular calcium elevation to 5.2 mM and isoproterenol (1 microM) addition. The ultrastructure of the myocardium was examined in the papillary muscle. The training effectiveness was verified by improvement of myocardial metabolic enzyme activities. Both 20% and 50% food restriction protocols presented minor body and ventricular weights gain. The 20%-FR, in sedentary or trained rats, did not alter myocardial function or ultrastructure. The 50%-FR, in sedentary rats, caused myocardial dysfunction under basal condition, decreased response to inotropic stimulation, and promoted myocardial ultrastructural damage. The 50%-FR, in exercised rats, increased myocardial dysfunction under basal condition but increased response to inotropic stimulation although there was myocardial ultrastructural damage. In conclusion, the exercise training in severe restriction caused marked myocardial dysfunction at basal condition but increased myocardial response to inotropic stimulation.

3-Hydroxyacyl CoA Dehydrogenases↗

The effect of exercise training on leptin levels in obese males.

The effect of endurance training on plasma leptin levels was investigated in 15 obese male subjects (age 37.3 +/- 5.2 yr, body weight 96.5 +/- 13.6 kg, and body mass index 29.8 +/- 3.0 kg/m2) in a weight loss and exercise program. After 4 mo of treatment consisting of a very low energy diet (VLED) and endurance exercise training (3-4 times weekly, 1 h sessions, moderate intensity), two groups were formed. One group continued the exercise sessions (trained subjects, n = 7) and the other group stopped with the exercise program (control, n = 8). Measurements of anthropometry, aerobic power, and fasted blood samples were executed at fixed time points (0, 2, 4, 10, and 16 mo). With partial regression analysis, keeping the changes in insulin and body fat percentage constant, it was shown that the number of hours of exercise training was significantly correlated with changes in leptin levels, during the 16-mo period (r = 0.56, P < 0.05). Changes in insulin levels were significantly related to the changes in leptin levels (r = 0.47, P < 0.05), which were less for changes in body fat percentage (r = 0.42, P = 0.07). During the VLED, the change in insulin concentration affected leptin levels significantly (r = 0.79) but changes in body fat percentage were not noted. It is concluded that endurance exercise training decreased plasma leptin levels independently of changes in plasma insulin levels and body fat percentage.

Adipose Tissue↗

Exercise training after cardiac transplantation.

During the last decade, cardiac transplantation has become the accepted form of treatment for selected patients with end-stage heart disease, which usually results from dilated cardiomyopathy or coronary artery disease. Although 5-yr survival is currently 85%, patients have complicated courses after surgery, with an ever present risk of infection and graft rejection. Because of physical inactivity and severe limitation of cardiac output preoperatively, these deconditioned patients are excellent candidates for medically supervised rehabilitative exercise training programs. Denervation of the myocardium, which occurs with cardiac transplantation, results in a loss of autonomic nervous system modulation of cardiac output, with reliance on circulating catecholamines and with a delayed heart rate and cardiac output response to the onset of exercise. Oxygen uptake kinetics are prolonged, and maximal oxygen uptake is reduced. Additional abnormalities in cardiac and pulmonary artery pressures and in ventilation during exercise have been described. The literature contains seven studies concerning the effects of exercise training in cardiac transplant recipients. Benefits resulting from training include increases in maximal oxygen uptake, peak exercise power output, anaerobic threshold, and lean body mass, reduced perceived exertion, heart rate, and blood pressure during submaximal exercise, and a lowered resting heart rate and blood pressure. There are no data to suggest that exercise training alters the incidence of infection or rejection or improves longevity or return to pre-illness lifestyle.

Coronary Disease↗

SERCA2a and mitochondrial cytochrome oxidase expression are increased in hearts of exercise-trained old rats.

Aging of rats results in slower activities of calcium transport by cardiac calcium adenosinetriphosphatase (ATPase) of the sarcoplasmic reticulum (SR) and mitochondrial cytochrome oxidase (COX). These enzyme activities are faster after exercise training of previously sedentary old rats. Our purpose was to determine whether the expression of the genes encoding SR calcium ATPase (SERCA2a) or COX is altered by exercise training. Old (24-mo-old) male Fischer 344 rats were assigned to SO (sedentary old) or EO (exercised old) groups and compared with younger (12-mo-old) sedentary rats (SM). EO rats were trained on a treadmill for 8-10 wk. SERCA2a and COX mRNAs were lower (P < 0.05) in SO compared with SM and EO, whereas glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and cardiac alpha-actin mRNAs were similar across groups. The immunoreactive protein contents of cardiac calcium ATPase, cytochrome c, sarcomeric actin, and GAPDH followed the changes, when observed, in mRNA contents. Thus pretranslational mechanisms may be modified in some genes during aging and exercise training of previously sedentary old rats.

Aging↗

Effects of eccentric exercise training on cortical bone and muscle strength in the estrogen-deficient mouse.

The purpose of this study was to determine whether eccentrically biased exercise training could attenuate changes in muscle and bone function associated with estrogen deficiency in the mouse model. Four groups of ICR mice were used: control (Con), sham ovariectomized (Sham), ovariectomized (OVX), and ovariectomized + high-force resistance training (OVX+Train). All groups except Con were implanted with a nerve cuff surrounding the peroneal nerve to stimulate the left ankle dorsiflexors. Training consisted of 30 stimulated eccentric contractions of the left ankle dorsiflexors at approximately 150% of peak isometric torque every third day for 8 wk. After the training period, groups were not significantly different with regard to peak torque or muscle size. However, the tibial midshaft of the trained leg in the OVX+Train mice exhibited greater stiffness (+15%) than that in the untrained OVX mice, which could not be explained by changes in cross-sectional geometry of the tibia. Scaling of bone mechanical properties to muscle strength were not altered by ovariectomy or training. These data indicate that eccentric exercise training in adult mice can significantly increase bone stiffness, despite the absence of ovarian hormones.

Animals↗

Effects of exercise training on insulin response to intravenous glucose in pubertal rats.

This study was undertaken to evaluate the effects of exercise training on glucose tolerance and glucose-stimulated insulin response (GSIR) in 55- and 90-day-old peripubertal female rats. Intravenous glucose tolerance tests (0.5 g/kg) were done in: 1) 90-day-old rats exercised in swimming sessions for either 5 or 10 weeks and evaluated 48 h after the last exercise bout; 2) 55-day-old rats exercised for 5 weeks and evaluated either 24 h or 48 h after the last exercise bout and; 3) unexercised 55- and 90-day-old rats. The total area under the GSIR curve was suppressed in 55- and 90-day-old rats exercised since the age of 21 days. However, this decrease was observed 48 and only 24 h after the last exercise bout in the 90- and 55-day-old rats respectively. Exercise did not affect the GSIR curve for the 90-day-old rats subjected to 5 weeks of exercise training (started at 55 days of age) when evaluated 48 h after the last exercise bout. Nor did one single bout of swimming exercise (2 h) in the last 24 h affect the GSIR in unexercised 55-day-old rats. These results suggest that the shorter duration of the residual effects of exercise in the younger rats (55 days) was related to the shorter length of the training programme. Body weight was not significantly reduced with exercise in 55-day-old rats, whereas the same amount of exercise in 90-day-old rats caused body weight reduction of approximately 35 g (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effects of experimental type 1 diabetes and exercise training on angiogenic gene expression and capillarization in skeletal muscle.

Diabetes alters microvascular structure and function and is a major risk factor for cardiovascular diseases. In diabetic skeletal muscle, impaired angiogenesis and reduced VEGF-A expression have been observed, whereas in healthy muscle exercise is known to have opposite effects. We studied the effects of type 1 diabetes and combined exercise training on angiogenic mRNA expression and capillarization in mouse skeletal muscle. Microarray and real-time PCR analyses showed that diabetes altered the expression of several genes involved in angiogenesis. For example, levels of proangiogenic VEGF-A, VEGF-B, neuropilin-1, VEGFR-1, and VEGFR-2 were reduced and the levels of antiangiogenic thrombospondin-1 and retinoblastoma like-2 were increased. Exercise training alleviated some of these changes, but could not completely restore them. VEGF-A protein content was also reduced in diabetic muscles. In line with the reduced levels of VEGF-A and other angiogenic factors, and increased levels of angiogenesis inhibitors, capillary-to-muscle fiber ratio was lower in diabetic mice compared to healthy controls. Exercise training could not restore capillarization in diabetic mice. In conclusion, these data illustrate that type 1 diabetes is associated with reduced skeletal muscle capillarization and the dysregulation of complex angiogenesis pathways.

Angiogenesis Inducing Agents↗

Effects of a short-term exercise training program on aerobic fitness, fatigue, health perception and activity level of subjects with multiple sclerosis.

Multiple sclerosis (MS) patients of an inpatient rehabilitation program have been randomly assigned to an exercise training (MS-ET) or nontraining group (MS-NI). Before and after 4 weeks of aerobic exercise training, a graded maximal exercise test with measurement of gas exchange and a lung function test was administered to all 26 patients fulfilling the inclusion criteria. Activity level, fatigue and health perception were measured by means of questionnaires. Twenty-six healthy persons served as control group and were matched in respect of age, gender and activity level. Training intervention consisted of 5x30 min sessions per week of bicycle exercise with individualised intensity. Compared with baseline, the MS training group demonstrated a significant rightward placement of the aerobic threshold (AT) (VO2+13%; work rate [WR])+11%), an improvement of health perception (vitality+46%; social interaction+36%), an increase of activity level (+17%) and a tendency to less fatigue. No changes were observed for the MS-NI group and the control groups. Maximal aerobic capacity and lung function were not changed by either training or nontraining in all four groups. Overall compliance to the training program was quite low (65%), whereas incidence of symptom exacerbation by physical activity has been lower than expected (6%).

Adult↗

Time course of sympathoadrenal adaptation to endurance exercise training in man.

One possible reason for the lower exercise heart rate after endurance exercise training is that the sympathetic drive to the heart is reduced. We have studied the relationship between plasma catecholamines and heart rate during exercise in the course of a 7-wk training program. Six untrained subjects exercised vigorously (on bicycle ergometers and by running) 30--50 min/day for 7 wk. Prior to the beginning of training and at weekly intervals thereafter, participants were subjected to a 5-min strenuous bicycle ergometer test. In the test prior to training, plasma epinephrine increased to 0.5 ng/ml and norepinephrine increased to 3.0 ng/ml. The major proportion of the training-induced decrement in catecholamine response was reached at the end of the 3rd wk when epinephrine increased to 0.17 ng/ml and norepinephrine increased to 1.5 ng/ml in response to the same test. Heart rate during exercise continued to decrease even after the catecholamine response had plateaued, implying that the reduced sympathetic response is not solely responsible for the reduced exercise heart rate.

Adaptation, Physiological↗

Influence of endurance exercise training status and gender on postexercise hypotension.

In sedentary individuals, postexercise hypotension after a single bout of aerobic exercise is due to a peripheral vasodilation. Endurance exercise training has the potential to modify this response and perhaps reduce the degree of postexercise hypotension. We tested the hypothesis that endurance exercise-trained men and women would have blunted postexercise hypotension compared with sedentary subjects but that the mechanism of hypotension would be similar (i.e., vasodilation). We studied 16 endurance-trained and 16 sedentary men and women. Arterial pressure, cardiac output, and total peripheral resistance were determined before and after a single 60-min bout of exercise at 60% peak oxygen consumption. All groups exhibited a similar degree of postexercise hypotension (approximately 4-5 mmHg; P < 0.05 vs. preexercise). In sedentary men and women, hypotension was the result of vasodilation (Deltaresistance: -8.9 +/- 2.2%). In endurance-trained women, hypotension was also the result of vasodilation (-8.1 +/- 4.1%). However, in endurance-trained men, hypotension was the result of a reduced cardiac output (-5.2 +/- 2.4%; P < 0.05 vs. all others) and vasodilation was absent (-0.7 +/- 3.3%; P < 0.05 vs. all others). Thus we conclude the magnitude of postexercise hypotension is similar in sedentary and endurance-trained men and women but that endurance-trained men and women achieve this fall in pressure via different mechanisms.

Adult↗