Physical exercises have been associated with important and varied benefits to health, as those related to the specific and non-specific immune function, stressing the inflammatory process in the latter. However, depending on their type, intensity, frequency and duration, exercises can also cause certain harm to the organism. Actually, previous research has demonstrated that the hypernociception of inflammatory origin in rats was influenced by the physical exercises protocol performed on treadmill. Thus, the aim of this research was to study the effects of high and low intensity physical exercises on acute inflammatory response. Therefore, male adult Wistar rats were submitted (trained group) or not (untrained group) to physical exercises on a treadmill. Acute inflammation was induced by a 0.5% carrageenin injection into the plantar tissue of the left hind paw of each rat and the acute inflammatory edema volume was measured by plethysmography before and after 1, 2, 3, 4, 6, 8 and 24 hours of the inflammatory process induction. The statistical analysis of the results showed a significant increase in the edema volume in times H1, H2 and H3 (P<0.01) and in times H4 and H6 (P<0.05) in animals submitted to low intensity exercises. However, no statistically significant changes occurred in the acute inflammatory edema volume in any of the evaluated times (P>0.05) in animals of the high intensity group compared with the non-trained group. Therefore, it was concluded that low-intensity physical exercises on treadmill increased the acute inflammatory edema volume in rats, probably due to the increase in the synthesis and secretion of prostaglandins and/or increase in the plasmatic levels of cytokines IL-1, IL-6 and TNF-alfa among other factors. This fact has not been observed in animals submitted to high intensity exercises, which demonstrates the influence of intensity, frequency and duration of the exercises on this inflammatory parameter.
physical exercises; treadmill; acute inflammation; edema; rats
