Influência de diferentes intensidades de treinamento aeróbio com sessões isocalóricas sobre a composição corporal, capacidade cardiorrespiratória e reatividade microvascular de ratos eutróficos

• Autor(a) principal: Paes, Lorena da Silva
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/12782
• topic: Microcirculation; VO2 máx; Vasodilation; Wistar Rats; Exercise physiology; Physical fitness; Microcirculação - Fisiologia; Consumo de Oxigênio - Fisiologia; Vasodilatação - Fisiologia; Exercícios aeróbicos - Aspectos fisiológicos; Aptidão física - Aspectos fisiológicos; Microcirculação; VO2 máx; Vasodilação; Ratos Wistar; Fisiologia do Exercício; Aptidão física; CNPQ::CIENCIAS BIOLOGICAS::FISIOLOGIA::FISIOLOGIA DO ESFORCO

There is evidence that high-intensity aerobic exercise would be more effective to improve cardiovascular and metabolic markers. However, previous research comparing the effect of aerobic training with different intensities did not control for the exercise volume through caloric expenditure assessment. Thus, the relative role of training intensity and volume remains unclear. This study investigated the influence of different intensities of aerobic training under isocaloric conditions on body composition, cardiorespiratory capacity and microvascular reactivity in eutrophic rats. Male Wistar rats (n=30) were assigned into three experimental groups: sedentary control (SED), high-intensity training (ALT), and moderate-intensity training (MOD). The ALT and MOD groups were submitted to training on treadmill for 4 weeks, running at speeds corresponding to 50% and 80% of maximal reserve oxygen uptake (VO2R). The duration of exercise sessions was controlled by caloric expenditure, which was the same in both groups (MOD=3.4±0.3 e ALT=3.2±0.3 kcal; P =0.61). At the end of intervention the groups underwent assessments of body composition (DEXA), cardiorespiratory capacity (VO2 max test) and microvascular reactivity (endothelium-dependent and independent vasodilation by means of intravital microscopy). In comparison to SED, only ALT presented lower fat mass (ALT=101.2±3.0 g vs. SED=124.8±2.0 g; P=0.01) and % fat (ALT=29.8±1.0% vs. SED=35.5±1.0%; P=0.03). The VO2 max increased in both exercised groups vs. SED (P<0,01), but the improvement was higher in ALT than MOD (P=0.0002) (∆ SED= -3.7±3.0 ml.kg-1.min-1; ∆ ALT= 4.9±2.0 ml.kg-1.min-1; ∆ MOD= 2.5±3.0 ml.kg-1.min-1). Both MOD and ALT similarly improved maximal endothelial-dependent vasodilation in comparison with SED (P< 0.05) in response to ACh (MOD=21.5% vs. ALT=20.8%; P=0,73) but did not differ among them (P=0,73). In endothelium-independent vasodilation maximum SNP-induced (10-4), only ALT group has significantly improved (MOD=10,7% e ALT=23,2%) in comparison with SED (p<0,05), but did not differ from MOD (p=0,67). Isocaloric sessions of aerobic training performed with high-intensity were more effective to improve adiposity and physical cardiorespiratory capacity in eutrophic rats. However, the endothelial function improved similarly in both trained groups. Thus, the total caloric expenditure of exercise sessions (volume) appeared to be more important than intensity to increase microvascular reactivity in the observed animals.