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PubMedDate not supplied

Aerobic exercise training fails to lower hypertriglyceridemia levels in persons with advanced HIV-1 infection.

The purpose of this study was to determine whether blood lipid and lipoprotein concentrations varied in 5 men with advanced HIV-1 infection after 12 months of aerobic exercise training. Prior to exercise, the mean baseline cholesterol and high-density lipoprotein cholesterol (HDL-C) serum concentration were each lower, and mean baseline triglyceride concentration was higher compared to a healthy population norm. Consistent exercise training for 12 months failed to significantly (p > .05) alter cholesterol or HDL-C. Triglyceride concentration was significantly (p < .05) elevated above baseline (63 mg/dL) regardless of exercise compliance. The results suggest that long-term exercise training cannot correct lipid profile abnormality, particularly hypertriglyceridemia, common to individuals with advanced HIV-1 infection.

CD4 Lymphocyte Count↗

PubMed2001

Effects of exercise training on myocardial fatty acid metabolism in rats with depressed cardiac function induced by transient ischemia.

The effects of exercise training on metabolic and functional recovery after myocardial transient ischemia were investigated in a rat model. Male Wistar Kyoto rats were subjected either to a 30-min left coronary artery occlusion followed by reperfusion or to a sham operation. At 4 weeks after operation, the rats were randomly assigned either to sedentary conditions or to exercise training for 6 weeks. In the ischemic rats, pinhole SPECT (single photon emission computed tomography) imaging with thallium-201 (201Tl) and 123I-(rho-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) showed a reduction of both myocardial perfusion and fatty acid metabolism in the risk zone of the left ventricle (LV). The LV was dilated and the ejection fraction was decreased after ischemic injury. The severity score showed a significant decrease on both 201Tl and BMIPP (201Tl, from 19.9+/-2.7 to 17.0+/-2.2, p<0.05; BMIPP, from 21.5+/-2.4 to 18.6+/-1.9, p<0.05) after exercise training in the ischemic trained rats, but did not change significantly in their sedentary counterparts. Plasma levels of free fatty acids normalized in the ischemic trained rats, but elevated in the ischemic sedentary rats (0.53+/-0.05 vs 0.73+/-0.06 mmol/L, p<0.05). Furthermore, the trained rats had a significant increase in LV stroke volume (0.25+/-0.02 vs 0.21+/-0.01 ml/beat, p<0.05) and adaptive cardiac hypertrophy. These findings demonstrate that adaptive improvements in myocardial perfusion, fatty-acid metabolism and LV function were induced by exercise training after transient ischemia.

Animals↗

PubMed2002

Exercise training and glycemic control in adolescents with poorly controlled type 1 diabetes mellitus.

This study sought to establish whether the glycemic control achieved in exercise-trained adolescents with type 1 diabetes mellitus (DM) is dependent on the quality of glycemic control prior to the initiation of exercise training. Adolescents with type 1 DM were randomly assigned to groups with either lower or higher than 9% glycosylated hemoglobin (HbA1c), and submitted to 12 weeks of supervised training followed by 12 weeks of unsupervised training (n = 12 per group). Supervised training caused a 17% rise in the patients' aerobic capacity which during the ensuing period of unsupervised training decreased to pre-training levels, thus suggesting a poor compliance with unsupervised training. The average levels of HbA1c in poorly and well controlled diabetic patients were not affected by training, a finding indicating that irrespective of the quality of glycemia prior to exercise training, glycemic control in adolescents with type 1 DM does not improve in response to exercise training alone.

Adolescent↗

PubMed2005

Home-based exercise training modulates pro-oxidant substrates in patients with chronic heart failure.

BACKGROUND: In chronic heart failure, oxidative stress is thought to lead to endothelial dysfunction. In this study, we assessed the effect of home-based exercise training on variables of the NO and purine pathways. METHODS AND RESULTS: Eighteen patients and nine controls were randomly assigned in cross-over design to 8 weeks of exercise training (5 days/week, submaximal bicycle ergometer training, 30 min/day; calisthenics 9 min/day) and 8 weeks of sedentary lifestyle. Hypoxanthine, xanthine, l-arginine, asymmetric dimethylarginine (ADMA), symmetric DMA (SDMA) and nitrite were measured. In patients, exercise training led to an increase in peak VO(2) (p<0.003). At baseline hypoxanthine-a pro-oxidant substrate and marker of hypoxia-was higher in patients than in controls (24.6+/-4.3 vs. 11.9+/-4.2 micromol/l; p<0.05). After training there was a reduction in hypoxanthine (p<0.01). Nitrite levels were lower in patients (416+/-31 micromol/l) than in healthy controls (583+/-35 micromol/l, p<0.001). Although nitrite levels were highest after exercise, the changes did not reach statistical significance (p=n.s.). l-Arginine, ADMA, and SDMA levels were not different between groups and were not altered by exercise training. CONCLUSIONS: Chronic heart failure is associated with increased levels of hypoxanthine and decreased levels of nitrite. This imbalance can be beneficially modulated by chronic home-based exercise training.

Adult↗

PubMed2005

Aerobic power and insulin action improve in response to endurance exercise training in healthy 77-87 yr olds.

Previous studies have demonstrated that frail octogenarians have an attenuated capacity for cardiovascular adaptations to endurance exercise training. In the present study, we determined the magnitude of cardiovascular and metabolic adaptations to high-intensity endurance exercise training in healthy, nonfrail elderly subjects. Ten subjects [8 men, 2 women, 80.3 yr (SD2.5)] completed 10-12 mo (108 exercise sessions) of a supervised endurance exercise training program consisting of 2.5 sessions/wk (SD 0.2), 58 min/session (SD 6), at an intensity of 83% (SD 5) of peak heart rate. Primary outcomes were maximal attainable aerobic power [peak aerobic capacity (Vo(2peak))]; serum lipids, oral glucose tolerance, and insulin action during a hyperglycemic clamp; body composition by dual-energy X-ray absorptiometry, and energy expenditure using doubly labeled water and indirect calorimetry. The training program resulted in an increase in Vo(2peak) of 15% (SD 7) [22.9 (SD 3.3) to 26.2 ml.kg(-1).min(-1) (SD 4.0); P < 0.0001]. Favorable lipid changes included reductions in total cholesterol (-8%; P = 0.002) and LDL cholesterol (-10%; P = 0.003), with no significant change in HDL cholesterol or triglycerides. Insulin action improved, as evidenced by a 29% increase in glucose disposal rate relative to insulin concentration during the hyperglycemic clamp. Fat mass decreased by 1.8 kg (SD 1.4) (P = 0.003); lean mass did not change. Total energy expenditure increased by 400 kcal/day because of an increase in physical activity. No change occurred in resting metabolism. In summary, healthy nonfrail octogenarians can adapt to high-intensity endurance exercise training with improvements in aerobic power, insulin action, and serum lipid and lipoprotein risk factors for coronary heart disease; however, the adaptations in aerobic power and insulin action are attenuated compared with middle-aged individuals.

Adaptation, Physiological↗

PubMed1988

High-intensity exercise training increases vascular transport capacity of rat hindquarters.

The purpose of this study was to determine whether high-intensity exercise training increases the vascular flow capacity and capillary exchange capacity in isolated rat hindquarters. One group of 20 male Sprague-Dawley rats underwent six bouts of alternating running (2.5 min) and recovery (4.5 min), 5 days/wk at 60 m/min on a 15% grade for 6-10 wk (high-intensity exercise training), while a second group of 20 rats was cage confined (sedentary controls). Experiments were conducted in isolated, maximally dilated (papaverine) hindquarters perfused with an artificial plasma consisting of a Tyrode's solution containing 5 g/100 ml albumin. Vascular flow capacity was evaluated by measuring perfusate flow rate at four different perfusion pressures. Capillary exchange capacity was evaluated by measuring the capillary filtration coefficient. The efficacy of training was demonstrated by significant increases in succinate dehydrogenase activity in the white vastus lateralis and vastus intermedius muscles. Total hindquarter flow capacity was elevated 50-100% in the trained rats. This increased flow capacity was associated with an increase in the capillary filtration coefficient in the maximally vasodilated hindquarters, thus suggesting that the capillary exchange capacity was increased with high-speed exercise training. These results suggest that the vascular transport capacity in rat hindquarter muscles is significantly increased by high-intensity exercise training.

Animals↗

PubMed2005

Comparison of low-frequency electrical myostimulation and conventional aerobic exercise training in patients with chronic heart failure.

BACKGROUND: Physical training is recommended as an efficient therapy in patients with chronic heart failure (CHF). Low-frequency electrical myostimulation (EMS) has recently been suggested as a good alternative to conventional aerobic training. The aim of this study was to compare the effects of EMS and conventional exercise training in patients with moderate to severe CHF. METHODS: Twenty-four patients with stable CHF (56.7+/-7.3 years, New York Heart Association grades II and III) underwent 5 weeks of exercise training, 5 h a week, using EMS (n=12) or conventional (n=12) training programmes. At baseline and after the training period, patients performed a symptom-limited cardiopulmonary test, a 6-min and a 200-m walk exercises and an evaluation of maximal knee extensor strength. RESULTS: Oxygen uptake (VO2) and workload at the end of exercise (peak values) and at ventilatory threshold increased after EMS (P< or =0.05) and conventional exercise (P<0.05) training programmes. The slope of the relationship between VO2 and workload was reduced after EMS (P<0.05). The time to recover half of peak VO2 decreased irrespective of the training programme (P<0.001). EMS and conventional exercise training programmes also increased the maximal knee extensor strength (P<0.05), the distance walked in 6 min (P<0.01) and decreased the time elapsed to cover 200 m (P<0.05). These improvements were not statistically different between EMS and conventional exercise. CONCLUSION: In patients with moderate to severe CHF, 5 weeks of EMS and conventional exercise training produce similar improvements to exercise capacity and muscle performance.

Aged↗

PubMed1994

Effects of exercise training on coronary circulation: introduction.

The purpose of this symposium was to evaluate the hypothesis that the beneficial effects of training are the result of training-induced adaptations in the coronary circulation. The approach is to review, summarize, and evaluate data concerning the effects of exercise training on the coronary circulation. Results indicate that aerobic exercise training induces an increase in both blood flow capacity and capillary exchange capacity. These functional changes are the result of two major types of adaptive responses: structural vascular adaptation and altered control of vascular resistance. Structural vascular adaptation occurs in response to exercise training in at least two forms: increases in the cross-sectional area of the proximal coronary arteries, and angiogenesis. Training-induced changes in coronary vascular control have been shown to include altered responses of the coronary circulation and isolated coronary arteries to vasoactive substances, changes in endothelium-mediated vasoregulation, and alterations in the cellular-molecular control of intracellular free Ca2+ in both endothelial and vascular smooth muscle cells isolated from coronary arteries of exercise trained animals. The potential impact of these training-induced adaptations on the coronary collateral circulation and atherosclerotic coronary disease are discussed.

Adaptation, Physiological↗

PubMed1998

Cardio-respiratory load of exercise training in patients with severe COPD.

The effect of physical training depends on the intensity at which exercise is performed. Patients with chronic obstructive pulmonary disease (COPD) may not tolerate high exercise intensities during training due to breathlessness. The purpose of the present study was to investigate the cardiorespiratory load of exercise training, during pulmonary rehabilitation, in patients with severe COPD. We also studied the effects of pulmonary rehabilitation on maximum exercise performance. Thirteen patients with stable COPD (FEV1 (S.D.) 1.0 (0.3) L) performed an incremental cycle exercise test at baseline and after a 10 week in-patient pulmonary rehabilitation programme. Exercise training consisted of dynamic and isometric strength training exercises, and training of specific daily life activities. Training sessions were held 5 days per week for 10 weeks. Heart rate (HR) and dyspnoea ratings (Borg scale) were measured during one session in the second or third week of training, and were compared with values obtained during incremental cycle exercise at baseline. The ventilatory load during the training was estimated by using the relationship between HR and minute ventilation (VE) during incremental cycle exercise at baseline. The duration of a training session was 80 (7) min, including periods of rest. The HR during various exercises of the training programme varied between 94 (17) and 103 (14)% of peak HR during incremental cycle exercise. Borg scores during the training varied between 2.0 and 5.7, and were lower than the Borg score at peak exercise (6.5 (2.0)). HR was more than 90% of peak HR during 36 (33) min of the whole training session, which corresponded with a VE of 81 (11)% of peak VE during incremental cycle exercise. Training significantly increased maximum work load (Wmax) from 62 (25) to 73 (21) W (P < 0.05), without any change in peak HR, VE and VO2. In patients with severe COPD, the training intensity in terms of cardio-respiratory load was high in relation to individual maximum values. Pulmonary rehabilitation, including exercise training, improved maximum exercise performance.

Aged↗

PubMed1998

Effects of moderate exercise training on thallium uptake and contractile response to low-dose dobutamine of dysfunctional myocardium in patients with ischemic cardiomyopathy.

BACKGROUND: There is evidence that exercise training can induce myocardial and coronary adaptations in both animals and humans. However, the significance of these potentially important changes remains to be determined in patients with ischemic heart disease and left ventricular (LV) systolic dysfunction. METHODS AND RESULTS: To investigate whether exercise training can improve thallium uptake and the contractile response to low-dose dobutamine of dysfunctional myocardium, 46 patients (42 men, 4 women; mean age, 57+/-9 years) with chronic coronary artery disease and impaired LV systolic function (ejection fraction < 40%) were randomly assigned to two groups. The exercise group (n = 26) underwent exercise training at 60% of peak oxygen uptake for 8 weeks. The control group (n = 20) was not exercised. At baseline and after 8 weeks all patients underwent an exercise test with gas exchange analysis and stress echocardiography using low-dose dobutamine (5 to 10 microg/kg per minute) followed by thallium myocardial scintigraphy. Coronary angiography was performed in 23 patients at baseline and after 8 weeks. After 8 weeks, peak oxygen uptake increased significantly only in trained patients (24%). Significant improvements in the contractile response to dobutamine and thallium activity were observed in trained patients (28% and 31%, respectively; trained versus control: P<.001 for both). In a subgroup of trained patients, both improvements were correlated with an increase in the coronary collateral score (P<.005 and P<.001, respectively). CONCLUSIONS: Moderate exercise training improves both thallium activity and the contractile response of dysfunctional myocardium to low doses of dobutamine in patients with ischemic cardiomyopathy. The implication of this study is that even a short-term exercise training may improve quality of life by improvement of LV systolic function during mild-to-moderate physical activity in patients with ischemic cardiomyopathy.

Adaptation, Physiological↗

PubMed2005

Effects of exercise training on papain-induced pulmonary emphysema in Wistar rats.

The purpose of the present study was to evaluate the role of exercise training on the development of papain-induced emphysema in rats. Our hypothesis was that the increase in pulmonary tissue stretching associated with exercise could increase the severity of a protease-induced emphysema. Wistar rats were randomly assigned to four groups (n = 10 for each group) that received, respectively, intratracheal infusion of papain (6 mg in 1 ml of 0.9% NaCl) or vehicle and were submitted or not to a protocol of exercise on a treadmill. Rats exercised at 13.3 m/min, 6 days/wk, for 9 wk (increasing exercise time, from 10 to 35 min). We measured respiratory system elastance and resistance, the size and weight of the heart, and pulmonary mean linear intercept (Lm). After 9 wk of exercise training, there were no differences in respiratory system resistance and elastance values among the four experimental groups. Volume of the heart was significantly greater in rats submitted to exercise training (P = 0.007) compared with sedentary rats due to increases in volumes of both right and left cardiac chambers. Lm was significantly greater in rats that received papain compared with saline-infused rats (P = 0.025). Surprisingly, this was true, even though there was no significant decrease in elastance, possibly due to connective tissue remodeling. However, Lm was significantly greater in papain + exercise rats compared with rats that received papain and were not submitted to exercise. We conclude that exercise training can increase alveolar damage induced by papain infusion.

Airway Resistance↗

PubMed2006

[Recommendations for planning and realisation of exercise training in outpatient lung sports groups].

Asthma and COPD are common diseases inducing high costs. In national and international guidelines exercise training is stated as the main component amongst the nonmedical treatment options. With exercise training beneficial effects in exercise performance, quality of life and health-related costs can be obtained. Options for exercise training all over the country should be established. Therefore not only inpatient, but also outpatient structures, especially lung sports groups have to be organized to enable a continuous training. For this special way of long term training no systematic guidelines do exist. Further aggravating factors are the different basic vocational education of the trainers and the heterogeneity of the participants. The intention of the authors was to develop recommendations for a structured training and training sensitive to the target group. The realisation of training with this approach should approximate training to evidence based knowledge and contribute to the quality of training patients with lung diseases.

Asthma↗

PubMed1997

Reduced ischemia and reperfusion injury following exercise training.

We examined the effects of two exercise training modalities, i.e., low-intensity endurance and sprint running, on in vitro, isovolumic myocardial performance following ischemia and reperfusion. Rats ran on a treadmill 5 d.wk-1 for 6 wk at the following levels: endurance; 20 m.min-1, 0% grade, 60 min.d-1 and sprint; five 1-min runs at 75 m.min-1, 15% grade interspersed with 1-min active recovery runs at 20 m.min-1, 15% grade. Both endurance and sprint training significantly improved exercise tolerance relative to control (P < 0.05) on two graded exercise tests. Buffer perfused hearts of control (N = 18), endurance (N = 20), and sprint (N = 13) trained animals underwent no-flow ischemia (20 min) and reperfusion (30 min) in a Langendorff mode. During reperfusion, left ventricular developed pressure and its first derivative were 20% higher in sprint (P < 0.05) than either endurance or control hearts. Left ventricular end-diastolic pressure was lowest in sprint during reperfusion (sprint, 10 +/- 1 mm Hg vs endurance, 14 +/- 2 mm Hg; and control, 14 +/- 2 mm Hg, at 30 min reperfusion). Hearts were then used for biochemical studies or dissociated into single cells for measurement of contraction, cell calcium, and action potential duration. Single cell contractions were greatest in sprint despite similar calcium transients in all groups. Ischemia/reperfusion caused action potential prolongation in control but not trained myocytes. Hearts from sprint had the greatest glyceraldehyde-3-phosphate dehydrogenase activity (P < 0.05) and a tendency towards increased superoxide dismutase activity. These results suggest that sprinting increases myocardial resistance to ischemia/reperfusion. This protection may be secondary to increased myofilament calcium sensitivity and/or myocardial expression of glyceraldehyde-3-phosphate dehydrogenase.

Animals↗

PubMed1994

Exercise training confers anticipatory protection from sudden death during acute myocardial ischemia.

Seven conscious dogs documented to be at high risk by the occurrence of ventricular fibrillation (VF) during acute myocardial ischemia were randomly assigned to 6 weeks of either daily exercise training or cage rest followed by exercise training. After 6 weeks of daily treadmill training, heart rate variability, a marker of vagal tone, increased by 74% (P < .001); baroreflex sensitivity, a marker of the capability to reflexly augment vagal activity, increased by 69% (P < .01); the repetitive extrasystole threshold, a marker of ventricular electrical stability, increased by 44% (P < .05). After exercise training, the incidence of ventricular fibrillation during acute myocardial ischemia decreased by 100%, as all animals survived. Neither passage of time nor heart rate level during ischemia contributed to the outcome. The most likely mechanism to explain the striking change in risk status is the shift in autonomic balance characterized by increased cardiac vagal activity, which was previously shown to have an antifibrillatory effect. These results suggest that exercise training in healthy individuals may decrease their likelihood of developing lethal arrhythmias during acute myocardial ischemia.

Acute Disease↗

PubMed1981

Effect of exercise-training on the metabolic manifestations of streptozotocin-induced diabetes in the rat.

Streptozotocin-induced insulin deficiency of a moderate degree was produced in exercise-trained and sedentary young rats, and determinations made of subsequent changes in plasma glucose, triglyceride, and insulin concentrations. Exercise-training attenuated the rise in both plasma glucose and triglyceride concentrations associated with insulin deficiency. Plasma insulin levels were, if anything, lower in exercise-trained rats. Thus, the beneficial effects of exercise-training on plasma glucose and triglyceride concentrations could not be due to the preservation of endogenous insulin secretion, and appear to be secondary to enhanced insulin sensitivity.

Animals↗

PubMed1997

Exercise training of moderate intensity does not abate the effects of denervation on muscle morphology.

Denervation elicits profound alterations in the morphometry of skeletal muscle. These alterations include changes in fiber type composition as well as reductions in fiber size. There is evidence that the increased mechanical load placed upon muscle via rhythmic stretching attenuates denervation induced alterations in muscle morphology. The purpose of the present study was to determine whether the mechanical stimuli associated with exercise training, i.e. rhythmic stretching and mechanical loading, would effectively moderate the changes in muscle morphometry observed following denervation. Unilateral denervation of the soleus muscle of eight male Sprague-Dawley rats was performed under aseptic conditions. The animals were then randomly assigned to two groups: sedentary controls and exercise trained. The exercise training protocol featured treadmill running five days per week for six weeks. At the conclusion of the experimental period, animals from both groups were sacrificed and soleus muscles were histochemically analyzed for muscle morphometry. Results demonstrated that denervation caused marked alterations in fiber type profile and in fiber cross-sectional areas. Interestingly, the degree of denervation induced atrophy appeared to be fiber type specific. However, the data presented here indicate that in denervated soleus muscles there were no significant differences in fiber type composition or fiber size between the sedentary and exercise trained groups. Hence, it appears that the mechanical stimuli provided by treadmill running of moderate intensity and duration are not sufficiently potent to ameliorate muscle morphometric responses to denervation.

Animals↗

PubMed2000

Aerobic exercise training fails to reduce blood pressure in nondipper-type hypertension.

To assess whether aerobic exercise training is an effective and an alternative method to control blood pressure (BP) in hypertension, 32 uncomplicated, never treated patients suffering from mild-to-moderate essential arterial hypertension (EAH) were included in an aerobic exercise training program using a regular standardized cycle ergometer exercise for 3 months. In all EAH patients, before and after the exercise training period, ambulatory BP monitoring (ABPM) was performed and several metabolic variables were assessed. Before exercise, in 20 EAH patients, a 48-h ABPM showed a normal day-night rhythm, with nocturnal BP decrease, according to a dipper-type hypertension, whereas in 12 EAH patients 48-h ABPM profile indicated a nondipper-type hypertension. After exercise, EAH dippers presented a significant decrease in the daytime systolic and diastolic BP, whereas EAH nondippers did not show any change in daytime and nighttime systolic and diastolic BP. Our study confirms the controversy about the postulated BP lowering effect of dynamic exercise in EAH patients, in the sense that only EAH dipper patients seem to obtain a beneficial diurnal lowering BP effect deriving from exercise, possibly through a reduction in sympathetic tone. On the contrary, physical activity seems to fail in reducing diurnal and nocturnal BP values in EAH nondippers, suggesting that in nondipper-type hypertension, other "masking" endogenous or exogenous factors could interfere with and prevail over the adrenergic-vagal balance that modulates the day-night BP synchronism.

Adult↗

PubMed1994

Effect of exercise training on the onset of type I diabetes in the BB/Wor rat.

The effects of regular exercise training on the onset and/or severity of hyperglycemia were studied in female diabetes-prone Biobreeding/Worcester (DP BB/Wor) rats. At 38-39 d of age, animals were weight-matched and randomly assigned to exercise-trained (T) and untrained (Unt) groups. The T rats exercised on a rodent treadmill at a moderate workload, 5 successive days with the 6th day being one of rest. Training lasted 5-11 wk until rats became moribund. Red gastrocnemius muscle citrate synthase activity was significantly higher in T (54.2 +/- 4.7 mumol.g-1.min-1) compared with Unt (42.9 +/- 5.1). No significant difference was found between the T and Unt groups in the following: age at onset of hyperglycemia (T = 82.9 +/- 8.7 d; Unt = 82.0 +/- 13.5 d, mean +/- SD), ultimate level of hyperglycemia, age of death (T = 89.9 +/- 9.2 d; Unt = 89.4 +/- 13.9 d), number of days between onset of hyperglycemia and death, or body weights at the onset of hyperglycemia. No significant difference was found between groups in pancreatic insulin concentration (microgram.g-1 of protein), T = 0.22 +/- 0.04; Unt = 0.20 +/- 0.34. These data suggest that a program of regular exercise training may not delay the onset and/or reduce the severity of hyperglycemia in the DP BB/Wor rat. Regular exercise training had no beneficial or detrimental effect on pancreatic beta-cell destruction.

Age of Onset↗