979 resultados para eccentric exercise
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Study Objectives: To test the effects of exercise training on sleep and neurovascular control in patients with systolic heart failure with and without sleep disordered breathing. Design: Prospective interventional study. Setting: Cardiac rehabilitation and exercise physiology unit and sleep laboratory. Patients: Twenty-five patients with heart failure, aged 42 to 70 years, and New York Heart Association Functional Class I-III were divided into 1 of 3 groups: obstructive sleep apnea (n = 8), central sleep apnea (n 9) and no sleep apnea (n = 7). Interventions: Four months of no-training (control) followed by 4 months of an exercise training program (three 60-minute, supervised, exercise sessions per week). Measures and Results: Sleep (polysomnography), microneurography, forearm blood flow (plethysmography), peak VO(2). and quality of life were evaluated at baseline and at the end of the control and trained periods. No significant changes occurred in the control period. Exercise training reduced muscle sympathetic nerve activity (P < 0.001) and increased forearm blood flow (P < 0.01), peak VO(2) (P < 0.01), and quality of life (P < 0.01) in all groups, independent of the presence of sleep apnea. Exercise training improved the apnea-hypopnea index, minimum O(2) saturation, and amount stage 3-4 sleep (P < 0.05) in patients with obstructive sleep apnea but had no significant effects in patients with central sleep apnea. Conclusions. The beneficial effects of exercise training on neurovascular function, functional capacity, and quality of life in patients with systolic dysfunction and heart failure occurs independently of sleep disordered breathing. Exercise training lessens the severity of obstructive sleep apnea but does not affect central sleep apnea in patients with heart failure and sleep disordered breathing.
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Background: Despite antihypertensive therapy, it is difficult to maintain optimal systemic blood pressure (BP) values in hypertensive patients (HPT). Exercise may reduce BP in untreated HPT. However, evidence regarding its effect in long-term antihypertensive therapy is lacking. Our purpose was to evaluate the acute effects of 40-minute continuous (CE) or interval exercise (IE) using cycle ergometers on BP in long-term treated HPT. Methods: Fifty-two treated HPT were randomized to CE (n=26) or IE (n=26) protocols. CE was performed at 60% of reserve heart rate (HR). IE alternated consecutively 2 min at 50% reserve HR with 1 min at 80%. Two 24-h ambulatory BP monitoring were made after exercise (postexercise) or a nonexercise control period (control) in random order. Results: CE reduced mean 24-h systolic (S) BP (2.6 +/- 6.6 mm Hg, p-0.05) and diastolic (D) BP (2.3 +/- 4.6, p-0.01), and nighttime SBP (4.8 +/- 6.4, p < 0.001) and DBP (4.6 +/- 5.2 mm Hg, p-0.001). IE reduced 24-h SBP (2.8 +/- 6.5, p-0.03) and nighttime SBP (3.4 +/- 7.2, p-0.02), and tended to reduce nighttime DBP (p=0.06). Greater reductions occurred in higher BP levels. Percentage of normal ambulatory BP values increased after CE (24-h: 42% to 54%; daytime: 42% to 61%; nighttime: 61% to 69%) and IE (24-h: 31% to 46%; daytime: 54% to 61%; nighttime: 46% to 69%). Conclusion: CE and IE reduced ambulatory BP in treated HPT, increasing the number of patients reaching normal ambulatory BP values. These effects suggest that continuous and interval aerobic exercise may have a role in BP management in treated HPT. (c) 2008 Elsevier Ireland Ltd. All rights reserved.
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Background: Patients with idiopathic pulmonary fibrosis (IPF) present an important ventilatory (imitation reducing their exercise capacity. Non-invasive ventilatory support has been shown to improve exercise capacity in patients with obstructive diseases; however, its effect on IPF patients remains unknown. Objective: The present study assessed the effect of ventilatory support using proportional, assist ventilation (PAV) on exercise capacity in patients with IPF. Methods: Ten patients (61.2 +/- 9.2 year-old) were submitted to a cardiopulmonary exercise testing, plethysmography and three submaximal. exercise tests (60% of maximum load): without ventilatory support, with continuous positive airway pressure (CPAP) and PAV. Submaximal tests were performed randomly and exercise capacity, cardiovascular and ventilatory response as well as breathlessness subjective perception were evaluated. Lactate plasmatic levels were obtained before and after submaximal. exercise. Results: Our data show that patients presented a limited exercise capacity (9.7 +/- 3.8 mL O(2)/kg/min). Submaximal. test was increased in patients with PAV compared with CPAP and without ventilatory support (respectively, 11.1 +/- 8.8 min, 5.6 +/- 4.7 and 4.5 +/- 3.8 min; p < 0.05). An improved arterial oxygenation and lower subjective perception to effort was also observed in patients with IPF when exercise was performed with PAV (p < 0.05). IPF patients performing submaximal exercise with PAV also presented a lower heart rate during exercise, although systolic and diastolic pressures were not different among submaximal tests. Our results suggest that PAV can increase exercise tolerance and decrease dyspnoea and cardiac effort in patients with idiopathic pulmonary fibrosis. (C) 2009 Elsevier Ltd. All rights reserved.
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We recently demonstrated that creatine supplementation increased some features of lung allergic sensitization in mice. On the other hand, other studies have shown that aerobic exercise inhibited allergic airway inflammation and remodeling. We hypothesized that aerobic exercise may decrease the exacerbatory effects of the creatine supplementation in a murine model of asthma. Balb/c mice were divided into six groups: Control, Creatine (Cr), Low Intensity Exercise + Creatine (Low + Cr), Ovalbumin (OVA), Ovalbumin + Creatine (OVA + Cr) and Ovalbumin + Creatine + Low Intensity Exercise (OVA + Cr + Low). OVA-sensitized groups were sensitized with OVA intraperitoneal injections (days 0, 14, 28, and 42). Aerosol challenge (OVA 1 %) and Cr treatment (0.5 g/kg/day) were initiated on Day 21 until Day 53. Low intensity exercise began on day 22 and was sustained until day 50. Low intensity exercise in the presence of creatine supplementation in sensitized mice resulted in a decreased number of eosinophils in BALF (p < 0.001) and in the airways (P < 0.001), and a decreased density of inflammatory cells positive to IL-4 (p < 0.001) and IL-5 (p < 0.001), airway collagen (p < 0.001) and elastic fibers (p < 0.001) content, airway smooth muscle thickness (p < 0.001) and bronchoconstriction index (p < 0.05) when compared with OVA + Cr group. These results suggest that aerobic exercise reduces the exacerbatory effects of creatine supplementation in chronically sensitized mice.
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Objective: This study assessed the effects of an aquatic respiratory exercise-based program in patients with fibromyalgia (FMS). Methods: Forty women, aged between 20 and 60 years, were randomly assigned into two groups of 20 patients: the aquatic respiratory exercise-based program (ARG) and the control group (CTL). The ARG group performed the exercise program for 1 h, four times a week, for 4 weeks which included: (i) warming-Lip; (ii) respiratory exercises, consisting of five different breathing patterns, along With upper, lower limbs and trunk movements (45 min); and (iii) relaxation exercises. Both groups were included in supervised recreational activities of 1 h, once a week, for 4 weeks. Questionnaires were applied before and after intervention to assess quality of life and functional capacity (SF-36, Fibromyalgia Impact Questionnaire [FIQ]), anxiety (Hamilton Anxiety Scale [HAS]), and quality of sleep (Pittsburg Sleep Quality Index [PSQI]). Number of tender points and pain (Visual Analogue Scale [VAS]) were also evaluated. Results: At baseline there was no difference between the two groups, including number of tender points and questionnaire responses. After intervention, the ARG group, compared with the CTL group, showed improvement in SF-36 scores (physical functioning P = 0.001, bodily pain 1) = 0.001, vitality P = 0.009, social functioning P = 0.001, emotional role P = 0.001), in FIQ (total score P = 0.049, work missed P = 0.036, fatigue P = 0.013, morning tiredness P = 0.007) plus in VAS-pain (P = 0.029), VAS-dyspnea (P = 0.04), anxiety (HAS P = 0.005) and quality of sleep (PSQI P = 0.004). Conclusions: The short-term aquatic respiratory exercise-based program improved pain, quality of life, functional capacity, anxiety and quality of sleep in patients with FMS and may be a relevant addition to the treatment of these patients.
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OBJECTIVE: The objective of the study was to evaluate the effect of a resistance exercise program with an elastic band on insulin requirement and glycemic control in patients with gestational diabetes mellitus (GDM). STUDY DESIGN: Sixty-four patients with gestational diabetes mellitus were randomly assigned into 2 groups: an exercise group (EG; n = 32) and a control group not submitted to the exercise program (CG; n = 32). RESULTS: A significant reduction in the number of patients who required insulin was observed in the EG (7/32) compared with the CG group (18/32) (P = .005). The percentage of time spent within the proposed target glucose range (of at least 80% of weekly measurements below the limits preestablished for the disease) was significantly higher in EG compared with the CG group (EG = 0.63 +/- 0.30; CG = 0.41 +/- 0.31; P = .006). CONCLUSION: The resistance exercise program was effective in reducing the number of patients with GDM who required insulin and in improving capillary glycemic control in this population.
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Our purpose was to examine possible influences of age on resistance exercise (RE) intensity progression in men. Twenty-four men, divided in young sedentary (YS; n = 10; 25.9 +/- 3.7 years), older sedentary (OS; n = 7; 67.4 +/- 5.2 years), and older runners (OR; n = 7; 71.3 +/- 3.0 years), underwent a 2 times-a-week RE program for 13 weeks. Muscle strength was assessed before and after training by 1-repetition maximum test. RE workloads were recorded for each exercise session, and increases of 5-10% were made whenever adaptation occurred. Muscle strength improved similarly in all groups after RE (P < 0.001). Relative RE intensity progression was not significantly different between YS and OS, except for a greater increase in calf raise relative workload observed in YS (P < 0.05). In contrast, OR displayed greater relative workload increase in 7 and 6 exercises than YS and OS, respectively (P < 0.05). The RE was safe as no injuries or major muscle pain were observed in either group. These results suggest that healthy sedentary older men are capable to exercise and increase RE intensity in the same way as young men, while physically active older men are capable to increase RE intensity in greater way than sedentary young and older men.
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Regarding all benefits of exercise training, a question remains: how long are these benefits kept? This study evaluated the effect of 3-week detraining after 10 weeks of training in STZ-diabetic rats. Male Wistar rats were assigned into: sedentary controls, trained controls, trained-detrained controls. sedentary diabetic, trained diabetic and trained-detrained diabetic. Arterial pressure (AP) and heart rate (HR) were recorded by a data acquisition system. Baroreflex sensitivity (BRS) was evaluated by HR responses to AP changes induced by infusion of vasoactive drugs. Intrinsic heart rate (IHR), sympathetic tonus (ST) and vagal tonus (VT) were evaluated by pharmacological blockade with atenolol and atropine. Spectral analysis of systolic AP and HR variabilities (HRV) was performed to estimate autonomic modulation to the heart and vessels. Diabetes cardiovascular and autonomic dysfunctions were reversed by exercise training and partially maintained in the 3-week detraining period. In controls, training decreased AP and HR and improved BRS. changes that returned to baseline values after detraining. IHR and VT were improved in trained diabetic rats and remained in detrained diabetic ones. LF component of HRV decreased in trained control group. In diabetics. exercise training improved variance, and absolute LF and HF components of HRV. Only HF was maintained in detrained diabetic group. Moreover, there was an inverse relationship between plasma glucose and the absolute HF component of HRV. These changes probably determined the different survival rate of 80% in diabetic detrained and 51% in diabetic sedentary rats. (c) 2008 Elsevier B.V. All rights reserved.
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Airway epithelium plays an important role in the asthma physiopathology. Aerobic exercise decreases Th2 response in murine models of allergic asthma, but its effects on the structure and activation of airway epithelium in asthma are unknown. BALB/c mice were divided into control, aerobic exercise, ovalbumin-sensitized and ovalbumin-sensitized plus aerobic exercise groups. Ovalbumin sensitization occurred on days 0, 14, 28, 42, and aerosol challenge from day 21 to day 50. Aerobic exercise started on day 22 and ended on day 50. Total cells and eosinophils were reduced in ovalbumin-sensitized group submitted to aerobic exercise. Aerobic exercise also reduced the oxidative and nitrosative stress and the epithelial expression of Th2 cytokines, chemokines, adhesion molecules, growth factors and NF-kB and P2X7 receptor. Additionally, aerobic exercise increased the epithelial expression of IL-10 in non-sensitized and sensitized animals. These findings contribute to the understanding of the beneficial effects of aerobic exercise for chronic allergic airway inflammation, suggesting an immune-regulatory role of exercise on airway epithelium. (C) 2011 Elsevier B.V. All rights reserved.
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P>1. Baroreceptors regulate moment-to-moment blood pressure (BP) variations, but their long-term effect on the cardiovascular system remains unclear. Baroreceptor deficit accompanying hypertension contributes to increased BP variability (BPV) and sympathetic activity, whereas exercise training has been associated with an improvement in these baroreflex-mediated changes. The aim of the present study was to evaluate the autonomic, haemodynamic and cardiac morphofunctional effects of long-term sinoaortic baroreceptor denervation (SAD) in trained and sedentary spontaneously hypertensive rats (SHR). 2. Rats were subjected to SAD or sham surgery and were then further divided into sedentary and trained groups. Exercise training was performed on a treadmill (five times per week, 50-70% maximal running speed). All groups were studied after 10 weeks. 3. Sinoaortic baroreceptor denervation in SHR had no effect on basal heart rate (HR) or BP, but did augment BPV, impairing the cardiac function associated with increased cardiac hypertrophy and collagen deposition. Exercise training reduced BP and HR, re-established baroreflex sensitivity and improved both HR variability and BPV. However, SAD in trained SHR blunted all these improvements. Moreover, the systolic and diastolic hypertensive dysfunction, reduced left ventricular chamber diameter and increased cardiac collagen deposition seen in SHR were improved after the training protocol. These benefits were attenuated in trained SAD SHR. 4. In conclusion, the present study has demonstrated that the arterial baroreflex mediates cardiac disturbances associated with hypertension and is crucial for the beneficial cardiovascular morphofunctional and autonomic adaptations induced by chronic exercise in hypertension.
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Intense lifestyle modifications can change the high-density lipoprotein (HDL) cholesterol concentration. The aim of the present study was to analyze the early effects of short-term exercise training, without any specific diet, on the HDL cholesterol plasma levels and HDL functional characteristics in patients with the metabolic syndrome (MS). We studied 30 sedentary subjects, 20 with and 10 without the MS. The patients with the MS underwent moderate intensity exercise training for 3 months on bicycle ergometers. Blood was sampled before and after training for biochemical analysis, paraoxonase-1 activity, and HDL subfraction composition and antioxidative capacity. Lipid transfer to HDL was assayed in vitro using a labeled nanoemulsion as the lipid donor. At baseline, the MS group had greater triglyceride levels and a lower HDL cholesterol concentration and lower paraoxonase-1 activity than did the controls. Training decreased the plasma triglycerides but did not change the low-density lipoprotein or HDL cholesterol levels. Nonetheless, exercise training increased the HDL subfractions` antioxidative capacity and paraoxonase-1 activity. After training, the MS group had compositional changes in the smallest HDL subfractions associated with increased free cholesterol and cholesterol ester transfers to HDL, reaching normal values. In conclusion, the present investigation has added relevant information about the dissociation between the quantitative and qualitative aspects of HDL after short-term exercise training without any specific diet in those with the MS, highlighting the importance of evaluating the functional aspects of the lipoproteins, in addition to their plasma levels. (C) 2011 Elsevier Inc. All rights reserved. (Am J Cardiol 2011;107:1168-1172)
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Ciolac, EG, Brech, GC, and Greve, JMD. Age does not affect exercise intensity progression among women. J Strength Cond Res 24(11): 3023-3031, 2010-It has been recommended that the intensity of exercise training (ET) should progress slowly with lower increments in older than in young people. However, scientific evidence supporting this recommendation is lacking. Our aim was to examine possible influences of age on exercise intensity progression in healthy women. Seventeen young (29.1 +/- 5.7 years) and 16 older women (64.5 +/- 4.5 years) underwent 13 weeks of ET consisting of cycle ergometry (CE, 65-75% of reserve heart rate), whole-body resistance exercise (RE, 60% of 1 repetition maximum [1RM]), and stretching. Muscle strength was assessed before and after ET by the 1RM. Cycle ergometry and RE workloads were recorded for each exercise session, and increases of 5-10% were made whenever adaptation occurred. Absolute muscle strength after ET improved (p < 0.001) in both groups, and there were no significant differences between groups. Relative exercise intensity progression was not significantly different between groups for RE (Pearson`s correlation = 0.98 +/- 0.01), but it was greater in older women for CE (p = 0.047). The ET was safe because no injuries or major muscle pain was observed in either group. These results suggest that healthy older women are capable of exercising and increasing exercise intensity in the same way as young women.
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Myocardial hypertrophy and dysfunction occur in response to excessive catecholaminergic drive. Adverse cardiac remodelling is associated with activation of proinflammatory cytokines in the myocardium. To test the hypothesis that exercise training can prevent myocardial dysfunction and production of proinflammatory cytokines induced by beta-adrenergic hyperactivity, male Wistar rats were assigned to one of the following four groups: sedentary non-treated (Con); sedentary isoprenaline treated (Iso); exercised non-treated (Ex); and exercised plus isoprenaline (Iso+Ex). Echocardiography, haemodynamic measurements and isolated papillary muscle were used for functional evaluations. Real-time RT-PCR and Western blot were used to quantify tumour necrosis factor alpha, interleukin-6, interleukin-10 and transforming growth factor beta(1) (TGF-beta(1)) in the tissue. NF-kappa B expression in the nucleus was evaluated by immunohistochemical staining. The Iso rats showed a concentric hypertrophy of the left ventricle (LV). These animals exhibited marked increases in LV end-diastolic pressure and impaired myocardial performance in vitro, with a reduction in the developed tension and maximal rate of tension increase and decrease, as well as worsened recruitment of the Frank-Starling mechanism. Both gene and protein levels of tumour necrosis factor alpha and interleukin-6, as well as TGF-beta(1) mRNA, were increased. In addition, the NF-kappa B expression in the Iso group was significantly raised. In the Iso+Ex group, the exercise training had the following effects: (1) it prevented LV hypertrophy; (ii) it improved myocardial contractility; (3) it avoided the increase of proinflammatory cytokines and improved interleukin-10 levels; and (4) it attenuated the increase of TGF-beta(1) mRNA. Thus, exercise training in a model of beta-adrenergic hyperactivity can avoid the adverse remodelling of the LV and inhibit inflammatory cytokines. Moreover, the cardioprotection is related to beneficial effects on myocardial performance.
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Menopause is recognized as a period of increased risk for coronary heart disease. Although the benefits of exercise training in lowering cardiovascular risk factors are well established, the risks and benefits of hormone therapy have been questioned. The purpose of the present study was to investigate the effects of estrogen therapy (HT) associated or not with exercise training (ET) in autonomic cardiovascular control in ovariectomized (OVX) rats. Female rats were divided into: control, OVX, OVX+HT, OVX+ET and OVX+HT+ET. HT was performed using a 0.25 mg 8-weeks sustained release pellet. Trained groups were submitted to an 8-week exercise training protocol on treadmill. Baroreflex sensitivity (BRS) was evaluated by heart rate responses to arterial pressure (AP) changes, and vagal and sympathetic tonus by pharmacological blockade. Ovariectomy induced an AP increase (123 +/- 2 mmHg vs. 108 +/- 2 mmHg), BRS impairment (similar to 69%), sympathetic activation (similar to 100%) and vagal tonus reduction (similar to 77%) compared to controls. HT or ET normalized the changes in parasympathetic tonus. However, only the association HT + ET was able to promote normalization of AP, BRS and sympathetic tonus, as compared to controls. These results indicate that ET induces cardiovascular and autonomic benefits in OVX rats under HT, suggesting a positive role of this association in the management of cardiovascular risk factor in postmenopausal women. (C) 2009 Elsevier Ireland Ltd. All rights reserved.