Effects Of Aerobic Physical Training Research Articles

Efeito do treinamento físico sobre o perfil metabólico e ósseo de ratos recém-desmamados

INTRODUCTION: The practice of moderate-intensity exercise can reduce the risk of infections and improve metabolic aspects of the person. OBJECTIVE: To investigate the effects of aerobic physical training on endocrine and metabolic aspects, bone and immune system. METHODS: Twenty Wistar rats were divided in two groups: sedentary (GS) and trained group (TG). Training program consisted in swimming, 6 weeks, supporting a workload corresponding to 5% of body weight. At the end of the experiment, were performed counting total and differential leukocyte count and hematocrit. After training period, were analyzed glucose, total protein, triglycerides, cholesterol, liver and muscle samples for the determination of the levels of glycogen, and determination of the tibia length and bone area. All dependent variables were analyzed by one-way analysis of variance (ANOVA) and a significance level of P < 0.05 was used for all comparisons. RESULTS: Hematocrit (%) analyzed showed a significant difference, with higher values ​​for TG (54.63 ± 1.41) than for the GS (49.5 ± 1.65). The total leukocyte count was not significantly different, as there was no difference in the differential count. Total cholesterol showed significant decrease in GT (GT = 68.27 ± 13.71 mg/dL; GS = 94.44 ± 28.09), the total protein levels also showed significant reduction (GT = 7.3 ± 0,40 g/dL; GS = 7.74 ± 0.36 g/dL) glucose levels and triglyceride showed no significant differences.The bone length showed a significant difference (GT = 40±0.14 mm; CG = 42.10 ± 0.12mm). The tibial area showed the lowest value for the GT (1.53 ± 0.12cm²) than for the GS (1.67 ± 0.18cm²) however the difference was not statistically significant. CONCLUSION: It can be concluded that aerobic exercise training is able to produce some unique physiological changes in young rats. There is also the need to prescribe exercises that meet the particular maturational stage of development.

Women with TT genotype for eNOS gene are more responsive in lowering blood pressure in response to exercise

The aim of this study was to investigate whether -786T>C endothelial nitric oxide synthase (eNOS) gene polymorphism might influence the effect of long-term exercise training (ET) on the blood pressure and its relationship with NO production in healthy postmenopausal women. Longitudinal study. Fifty-five postmenopausal women were studied in a double-blinded design. ET was performed for 3 days a week, each session consisting of 60 min during 6 months, in an intensity of 50-70% VO2max. After that, eNOS genotype analysis was performed and women were divided into two groups: TC+CC (n=41) and TT (n=14) genotype. No changes were found in the anthropometric parameters after ET in both the groups. Systolic and diastolic BP values were significantly reduced in both the groups, but women with TT genotype were more responsive in lowering BP as compared with those with TC+CC genotype. Plasma nitrite/nitrate concentrations were similar at baseline in both the groups, but the magnitude of increment in NO production in response to ET was higher in women with TT genotype as compared with those with TC+CC genotype. Our study shows clearly that women with or without eNOS gene polymorphism had no differences in NO production at basal conditions, but when physical exercise is applied an evident difference is detected showing that the presence of -786T>C eNOS gene polymorphism had a significant impact in the health-promoting effect of aerobic physical training on the blood pressure in postmenopausal women.

The effect of aerobic physical training on cardiac autonomic control of rats submitted to ovariectomy

To investigate the effect of aerobic physical training on cardiovascular autonomic control in ovariectomized rats using different approaches. Female Wistar rats were divided into four groups: sedentary sham rats (group SSR), trained sham rats(group TSR), sedentary ovariectomized rats (group SOR), and trained ovariectomized rats (group TOR). Animals from the trained groups were submitted to a physical training protocol (swimming) for 12 weeks. Pharmacological evaluation showed that animals from group TSR had an increase in their cardiac vagal tonus compared with the animals from groups SSR and SOR. The analysis of heart rate variability (HRV) showed that groups TSR and SOR had fewer low-frequency oscillations (0.20-0.75 Hz) compared with groups SSR and TOR.When groups TSR and SOR were compared, the former was found to have fewer oscillations. With regard to high frequency oscillations (0.75-2.5 Hz), group SSR had a reduction compared with the other groups, whereas group TSR had the greatest oscillation compared with groups SOR and TOR, with all values expressed in normalized units.Analysis of HRV was performed after pharmacological blockade, and low-frequency oscillations were found to be predominantly sympathetic in sedentary animals, whereas there was no predominance in trained animals. Ovariectomy did not change the tonic autonomic control of the heart and, in addition, reduced the participation of sympathetic component in cardiac modulation. Physical training, on the other hand, increased the participation of parasympathetic modulation on the HRV, including ovariectomized rats.

C-type natriuretic peptide expression in patients with chronic heart failure: effects of aerobic training

C-type natriuretic peptide (CNP) is structurally related to cardiac natriuretic peptides and is currently considered as an endothelium-derived hyperpolarizing factor. Endothelial dysfunction, commonly observed in chronic heart failure (HF) patients is positively affected by physical training. To evaluate the effect of aerobic physical training on the expression of CNP, 90 HF patients on optimal pharmacological treatment (age 62+/-2 years, mean+/-SEM), randomly assigned in a 3 : 1 ratio to either control group (C, 19 patients) or home-based aerobic exercise-training program group (T, 71 patients), completed the protocol. Plasma assay of CNP, brain natriuretic peptide or B-type natriuretic peptide (BNP), and norepinephrine; echocardiogram; and cardiopulmonary-stress test were performed in all patients at enrollment and after 9 months. At baseline, in both groups, CNP plasma level was significantly related to BNP (R=0.50), ejection fraction (R=0.43), and peak oxygen uptake (VO2, R=0.43, all P<0.001). After 9 months, trained patients showed an improvement in peak VO2 (P<0.001) and ejection fraction (P<0.05), whereas norepinephrine (P<0.05), BNP (P<0.001), and CNP (P<0.001) decreased. No changes occurred in group C. In group T, the decrease in CNP was significantly related to the increase in peak VO2 (R=0.31, P<0.01), and the relation between CNP and BNP was preserved at the end of the program (R=0.41, P<0.001). Clinical and functional improvement after physical training in HF patients is associated with a decrease in adrenergic activation and in both CNP and BNP concentration. Changes in CNP plasma concentration after physical training might reflect an improvement in endothelial function.

HEART RATE RESPONSE TO HEAD-UP TILTING IN SEDENTARY AND TRAINED SUBJECTS1010

The head-up tilting (HUT) has been used as a physiological test for evaluation of autonomic control of heart rate (HR). The aim of this study was to evaluate the effects of aerobic physical training on the autonomic control of HR. The studied groups included: 12 sedentary men (S) and 10 long distance runners (LDR). The ˙VO2 (peak and at anaerobic threshold - AT) was directly (MMC - Sensormedics) obtained using a exercise test with a continuous protocol (ramp function) up to physical exhaustion. The results (medians) for the variables used to characterize the groups were: resting HR(bpm): 69(S), 57(LDR) (p<0.05); ˙VO2 AT(ml/kg/min): 22.75(S), 43.55(LDR)(p<0.05); ˙VO2 peak(ml/kg/min): 38.15(S), 67.55(LDR)(p<0.05). The 70° HUT was performed during 15 min but the HR response was evaluated during the first 70 seconds of tilting. The trimmed mean(α=0.05) curve of the HR values in the time for the groups were adjusted using the smooth spline. The confidence interval of 95% showed that differences in the group-curves were not statistically significant. These data suggest that in spite of the occurrence of striking cardiorespiratory adaptations in the trained group, they were not accompanied by changes in the autonomic control of heart rate that could be measure by HUT.