RESUMO
The aim of research was to assess exercise-induced changes in mechanics of hearts isolated from rats, as well as time-course of those changes. Wistar rats (n = 42) were divided into control, moderately trained (swimming 1 hour, 5 days a week for 9 or 12 weeks) and strenuously trained (swimming 2, 3 and 4 times a day for an hour in weeks 10, 11 and 12, respectively) groups. After sacrificing, hearts (weight: 1480.82 ± 145.38 mg) were isolated and perfused on a Langendorff apparatus. Coronary perfusion pressure (CPP) was gradually increased (from 40 to 120 cm H(2)O) in order to establish coronary autoregulation. Parameters of cardiac contractility were recorded: maximum and minimum rate of change of pressure in the left ventricle (dp/dt max and dp/dt min), systolic and diastolic left ventricular pressure (SLVP and DLVP), heart rate (HR) and coronary flow (CF). Nine weeks of moderate exercise induced slight depression of coronary function (decrease of dp/dt max, dp/dt min, SLVP and DLVP), while 3 additional weeks of moderate training improved hearts function, but not to the extent that the strenuous training program did. The results of our study add evidence about beneficial effects of regular moderate exercise on heart, and furthermore, show that exercising frequently, if the intensity stays within moderate range, may not have detrimental effects on cardiodynamics.
Assuntos
Circulação Coronária/fisiologia , Frequência Cardíaca/fisiologia , Contração Miocárdica/fisiologia , Esforço Físico/fisiologia , Natação/fisiologia , Função Ventricular Esquerda/fisiologia , Adaptação Fisiológica/fisiologia , Animais , Tolerância ao Exercício/fisiologia , Feminino , Ratos , Ratos WistarRESUMO
The aim of this study was to determine the effects of a twelve-week aerobic dance-training program on the body composition parameters of young women. The sample of 59 young women belonged to one of two groups, an experimental (EXP) or a control (CON) group. The experimental group consisted of 29 female subjects (age 23.1+/-1.9 years, body height 164.4+/-6.1 cm, body weight 62.1+/-5.6 kg, BMI 23.0+/-2.2 kg/m2), while the control group was made up of 30 subjects (age 22.7+/-1.8 years, body height 165.3+/-6.2 cm, body weight 59.4+/-6.3 kg, BMI 21.7+/-1.7 kg/m2). To assess body compositions, the following measures were used: the overall sum of the upper body skinfolds, the overall sum of the lower body skinfolds, the overall sum of skinfolds of the upper and lower body, the percentage of body fat, the percentage of muscle mass in the body, body height and body weight. For all of the sums of skinfolds for the subjects of the EXP group, we noted a statistically significant decrease (p< 0.05) at the final measuring in relation to the initial measuring (SSFUPPER - 39.35 mm compared to 42.87 mm; S SFLOWER - 39.35mm compared to 49.88 mm; STOTAL SF - 76.97 mm compared to 92.75 mm). In the case of BF percent, a decrease was noted at the final measuring in relation to the initial one (20.37 percent compared to 22.66 percent), which was statistically significant (p< 0.05). On the basis of our results, we can conclude that aerobic dance decreases subcutaneous fatty tissue and body composition of the young women.
El objetivo de este estudio fue determinar los efectos de un programa de acondicionamiento de danza aeróbica de doce semanas sobre los parámetros de composición corporal de mujeres jóvenes. La muestra de 59 mujeres jóvenes se dividió en dos grupos, uno experimental y otro control. El grupo experimental estaba compuesto por 29 mujeres (edad 23,1 +/- 1,9 años, estatura 164,4 +/- 6,1 cm, peso corporal 62,1 +/- 5,6 kg, IMC 23,0 +/- 2,2 kg/m2), mientras que el grupo de control estaba compuesto por 30 mujeres (edad 22,7 +/- 1,8 años, estatura 165,3 +/- 6,2 cm, peso corporal 59,4 +/- 6,3 kg, IMC 21,7 +/- 1,7 kg/m2). Para evaluar la composición corporal, se utilizaron las siguientes medidas: la suma general de los pliegues cutáneos parte superior del cuerpo, la suma general de los pliegues cutáneos parte inferior del cuerpo, la suma general de los pliegues cutáneos de las partes superiores e inferiores del cuerpo, el porcentaje de grasa corporal, el porcentaje de masa muscular en el cuerpo, estatura y peso corporal. Al considerar todas las sumas de los pliegues cutáneos de las mujeres del grupo experimental, observamos una disminución estadísticamente significativa (p < 0,05) en la medición final en relación con la medición inicial (SPC SUPERIOR 39,35 mm en comparación con 42,87 mm; SPCINFERIOR 39,35 mm en comparación con 49,88 mm; SPC TOTAL 76,97 mm comparación con 92,75 mm). En el caso de porcentaje de grasa corporal, se observó una disminución en la medición final en relación al porcentaje inicial (20,37 por ciento en comparación al 22,66 por ciento) lo cual fue estadísticamente significativo (p < 0,05 ). Basado en los resultados de nuestro estudio, podemos concluir que la danza aeróbica disminuye el tejido graso subcutáneo y la composición corporal de las mujeres jóvenes.
