Divergent cytokine response following maximum progressive swimming in hot water.

Abstract

Exercise promotes transitory alterations in cytokine secretion, and these changes are affected by exercise duration and intensity. Consideringthat exercise responses also are affected by environmental factors, the goal of the present study was to investigate the effect of watertemperature on the cytokine response to maximum swimming. Swiss mice performed a maximum progressive swimming exercise at 31 or38C, and plasma cytokine levels were evaluated immediately or 1, 6 or 24 h after exercise. The cytokine profile after swimming at 31Cwas characterized by increased interleukin (IL)-6 and monocyte chemotactic protein-1 (MCP-1) levels, which peaked 1 h after exercise, sug-gesting an adequate inflammatory milieu to induce muscle regeneration. Transitory reductions in IL-10 and IL-12 levels also were observedafter swimming at 31C. The cytokine response to swimming was modified when the water temperature was increased to 38C. Althoughexercise at 38C also led to IL-6 secretion, the peak in IL-6 production occurred 6 h after exercise, and IL-6 levels were significantly lowerthan those observed after maximum swimming at 31C(p =0030). Furthermore, MCP-1 levels were lower and tumour necrosis factor-alevels were higher immediately after swimming at 38C, suggesting a dysregulated pro-inflammatory milieu. These alterations in the cyto-kine profile can be attributed in part to reduced exercise total work because exhaustion occurred sooner in mice swimming at 38C than inthose swimming at 31oC.