64 resultados para EXERCISE TRAINING IMPROVES

em University of Queensland eSpace - Australia


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This study examined the effects of four high-intensity interval-training (HIT) sessions performed over 2 weeks on peak volume of oxygen uptake (VO2peak), the first and second ventilatory thresholds (UT VT2) and peak power output (PPO) in highly trained cyclists. Fourteen highly trained male cyclists (VO2peak = 67.5 +/- 3.7 ml . kg(-1) . min(-1)) performed a ramped cycle test to determine VO2peak VT1 VT2, and PPO. Subjects were divided equally into a HIT group and a control group. The HIT group performed four HIT sessions (20 x 60 s at PPO, 120 s recovery); the V-02peak test was repeated <I wk after the HIT program. Control subjects maintained their regular training program and were reassessed under the same timeline. There was no change in V0(2peak) for either group; however, the HIT group showed a significantly greater increase in VT1, (+22% vs. -3%), VT2 (+15% vs. -1%), and PPO (+4.3 vs. -.4%) compared to controls (all P <.05). This study has demonstrated that HIT can improve VT1, VT2,, and PPO, following only four HIT sessions in already highly trained cyclists.

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The improvement of exercise capacity due to exercise training in heart failure has been associated with peripheral adaptation, but the contribution of cardiac responses is less clear. We sought the extent to which the improvement of functional capacity in patients undergoing exercise training for heart failure was related to myocardial performance. Thirty-seven patients (35 men, age 64 +/- 11) with symptomatic heart failure and left ventricular ejection fraction

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Atherosclerotic plaque contains apoptotic endothelial cells with oxidative stress implicated in this process. Vitamin E and a-lipoic acid are a potent antioxidant combination with the potential to prevent endothelial apoptosis. Regular exercise is known to increase myocardial protection, however, little research has investigated the effects of exercise on the endothelium. The purpose of these studies was to investigate the effects of antioxidant supplementation and/or exercise training on proteins that regulate apoptosis in endothelial cells. Male rats received a control or antioxidant-supplemented diet (vitamin E and alpha-lipoic acid) and were assigned to sedentary or exercise-trained groups for 14 weeks. Left ventricular endothelial cells (LVECs) were isolated and levels of the anti-apoptotic protein Bcl-2 and the pro-apoptotic protein Bax were measured. Antioxidant supplementation caused a fourfold increase in Bcl-2 (P < 0.05) with no change in Bax (P > 0.05). Bcl-2:Bax was increased sixfold with antioxidant supplementation compared to non-supplemented animals (P < 0.05). Exercise training had no significant effect on Bcl-2, Bax or Bcl-2:Bax either alone or combined with antioxidant supplementation (P > 0.05) compared to non-supplemented animals. However, Bax was significantly lower (P < 0.05) in the supplemented trained group compared to non-supplemented trained animals. Cultured bovine endothelial cells incubated for 24 h with vitamin E and/or a-lipoic acid showed the combination of the two antioxidants increased Bcl-2 to a greater extent than cells incubated with the vehicle alone. In summary, vitamin E and a-lipoic acid increase endothelial cell Bcl-2, which may provide increased protection against apoptosis. (c) 2005 Elsevier Ltd. All rights reserved

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Background: Exercise training has been shown to improve exercise capacity in patients with heart failure. We sought to examine the optimal strategy of exercise training for patients with heart failure. Methods: Review of the published data on the characteristics of the training program, with comparison of physiologic markers of exercise capacity in heart failure patients and healthy individuals and comparison of the change in these characteristics after all exercise training program. Results: Many factors, including the duration, supervision, and venue of exercise training; the volume of working muscle; the delivery mode (eg, continuous vs. intermittent exercise), training intensity; and the concurrent effects of medical treatments may influence the results of exercise training in heart failure. Starting in an individually prescribed and safely monitored hospital-based program, followed by progression to an ongoing and progressive home program of exercise appears to be the best solution to the barriers of anxiety, adherence, and ease of access encountered by the heart failure patient. Conclusions: Various exercise training programs have been shown to improve exercise capacity and symptom status in heart failure, but these improvements may only be preserved with an ongoing maintenance program.

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Background The reduction of exercise capacity because of fatigue and dyspnea in patients with heart failure can be improved with exercise training. We sought to examine the mechanisms of exercise training, as an adjunctive treatment strategy for patients with heart failure. Methods a reviewed the published data on the possible mechanisms of effect of exercise training in heart failure. Results Symptoms of heart failure may be explained on the basis of abnormal skeletal muscle perfusion and structure and endothelial function. Exercise training has been shown to engender changes in muscle structure and biochemistry and vascular function, although effects on cardiac function have not been detected uniformly and may require longer training periods. Conclusions A suitable, long-term program of exercise training may reverse unfavorable interactions among the heart, vessels, and skeletal muscles. These improvements may be preserved with an ongoing maintenance program.

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Peripheral arterial disease (PAD) is an obstructive condition where the flow of blood through peripheral arteries is impeded. During periods of increased oxygen demand (e.g. during exercise), peripheral limb ischaemia occurs, resulting in the sensation of muscle pain termed 'claudication'. As a result of claudication, subjects' ability to exercise is greatly reduced affecting their quality of life. Although many treatment options for patients with PAD exist, exercise training is an effective and low-cost means of improving functional ability and quality of life. Currently, there are limited specific recommendations to assist the exercise prescription and programming of these individuals. This review summarises data from 28 exercise training studies conducted in patients with PAD and formulates recommendations based on their results. Exercise training for patients with PAD should involve three training sessions per week comprising 45 minutes of intermittent treadmill walking in a supervised environment for a time period of 20 weeks or more. Encouragement and direction is given to further research aimed at investigating the effectiveness of training programmes in these patients.

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PURPOSE: To determine the efficacy of exercise training and its effects on outcomes in patients with heart failure. METHODS: MEDLINE, Medscape, and the Cochrane Controlled Trials Registry were searched for trials of exercise training in heart failure patients. Data relating to training protocol, exercise capacity, and outcome measures were extracted and reviewed. RESULTS: A total of 81 studies were identified: 30 randomized controlled trials, five nonrandomized controlled trials, nine randomized crossover trials, and 37 longitudinal cohort studies. Exercise training was performed in 2387 patients. The average increment in peak oxygen consumption was 17% in 57 studies that measured oxygen consumption directly, 17% in 40 studies of aerobic training, 9% in three studies that only used strength training, 15% in 13 studies of combined aerobic and strength training, and 16% in the one study on inspiratory training. There were no reports of deaths that were directly related to exercise during more than 60,000 patient-hours of exercise training. During the training and follow-up periods of the randomized controlled trials, there were 56 combined (deaths or adverse events) events in the exercise groups and 75 combined events in the control groups (odds ratio [OR] = 0.98; 95% confidence interval [Cl]: 0.61 to 1.32; P = 0.60). During this same period, 26 exercising and 41 nonexercising subjects died (OR = 0.71; 95% CT: 0.37 to 1.02; P = 0.06). CONCLUSION: Exercise training is safe and effective in patients with heart failure. The risk of adverse events may be reduced, but further studies are required to determine whether there is any mortality benefit. (C) 2004 by Excerpta Medica Inc.

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Inactivity is associated with endothelial dysfunction and the development of cardiovascular disease. Exercise training has a favourable effect in the management of hypertension, heart failure and ischaemic heart disease. These beneficial effects are probably mediated through improvements of vascular function and, in this issue of Clinical Science, Hagg and co-authors propose a coronary artery effect. The use of a Doppler technique for non-invasive assessment of coronary flow reserve in a small animal model is an exciting aspect of this study. If feasible in the hands of other investigators, the availability of sequential coronary flow measurements in animal models may help improve our understanding of the mechanisms of disorders of the coronary circulation.

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Erythrocytes transport oxygen to tissues and exercise-induced oxidative stress increases erythrocyte damage and turnover. Increased use of antioxidant supplements may alter protective erythrocyte antioxidant mechanisms during training. Aim of study: To examine the effects of antioxidant supplementation, (alpha-lipoic acid and a-tocopherol) and/or endurance training on the antioxidant defenses of erythrocytes. Methods: Young male Wistar rats were. assigned to (1) sedentary; (2) sedentary and antioxidant-supplemented; (3) endurance-trained; or (4) endurance-trained and antioxidant-supplemented groups for 14 weeks. Erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities, and plasma malondialdehyde (MDA) were then measured. Results: Antioxidant supplementation had no significant effect (p > 0.05) on activities of antioxidant enzymes in sedentary animals. Similarly, endurance training alone also bad no effect (p > 0.05). GPX (125.9 2.8 vs. 121.5 3.0 U.gHb(-1), p < 0.05) and CAT (6.1 0.2 vs. 5.6 0.2 U.mgHb-1, p < 0.05) activities were increased in supplemented trained animals compared to non-supplemented sedentary animals whereas SOD (61.8 4.3 vs. 52.0 5.2 U.mgHb(-1), p < 0.05) activity was decreased. Plasma MDA was not different among groups (p > 0.05). Conclusions: In a rat model, the combination of exercise training and antioxidant supplementation increased antioxidant enzyme activities (GPX, CAT) compared with each individual intervention.