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Revista Brasileira de Medicina do Esporte
On-line version ISSN 1806-9940
LANA, Ademir da Costa; PAULINO, Célia Aparecida and GONCALVES, Ivair Donizeti. Influence of low and high intensity physical exercise on hypernociception threshold and other parameters of rats. Rev Bras Med Esporte [online]. 2006, vol.12, n.5, pp. 248-254. ISSN 1806-9940. http://dx.doi.org/10.1590/S1517-86922006000500005.
Physical exercise practice is an important habit to maintain the physical and emotional well-being of those who regularly adopt it, and can bring great benefits to health. However, depending on the type, intensity, frequency and duration of the exercises, they can also do a certain degree of harm to the organism. As a benefit, the role of physical exercise is described in the specific and non-specific immune function and, in the latter, the inflammatory process stands out. Therefore, the purpose of this study was to show the effects of low and high intensity physical exercises on hypernociception, and to evaluate the body mass and the relative weight of some organs in rats. For the study, male adult Wistar rats were used and submitted (trained group) or not submitted (non-trained group) to physical exercises on an ergometric treadmill. The acute inflammation was induced by an injection of carrageenin-0.5% into the plantar tissue of the left hind paw of each rat and the nociception was measured by the plantar test before and after 1, 2, 3, 4, 6, 8 and 24 hours. At the end of the evaluations, the rats were submitted to deep anesthesia until their euthanasia, to collect and weigh the adrenal glands, heart, spleen and kidneys, and to subsequent histopathological study of those tissues. The statistical analysis of the results showed a significant increase (P < 0.05) of the hypernoniception threshold in H2, H3, H4 and H6 moments in animals trained at high intensity. There was also a significant reduction (P < 0.05) in body mass besides hypertrophy of the adrenal glands and heart and an increase in the kidneys relative weight of the rats trained at high intensity, in addition to adrenal hypertrophy of the animals trained at low intensity. There were no statistically significant changes in the other parameters evaluated in this study. We concluded that physical exercises on a treadmill were capable of changing the nociception, body mass and the relative weight of some organs, but in a way that was dependent on the exercises protocol applied to the animals.
Keywords : Physical exercises; Treadmill; Hipernociception; Rats.