Interleukin-6 response to isokinetic exercise in elite athletes: relationships to adrenocortical function and to mechanical and myoelectric fatigue

Abstract

Exercise stimulates the release of interleukin-6 (IL-6). Aims of the study were to: (a) analyse the IL-6 response to exercise in power (n = 7) and endurance athletes (n = 13); (b) determine the effects of the IL-6 production on mechanical and myoelectric fatigue; (c) evaluate the relationship between IL-6 and adrenocortical responses. EMG variables (conduction velocity, mean power frequency, average rectified value), ACTH, cortisol, DHEA, IL-6, myoglobin, and lactate were analysed before and after an isokinetic exercise. The exercise elicited significant mechanical and myoelectric fatigue as well as significant biochemical responses. Power athletes showed IL-6 and lactate responses higher than endurance athletes. The correlation analyses showed that the greater the mechanical fatigue, the greater the increases in lactate and IL-6. No correlations were found between IL-6 and EMG variables. No relationships were found between IL-6 and cortisol, after correction for ACTH levels. In conclusion, the muscular IL-6 production, as inferred by its circulating levels, had no detectable effects on the myoelectric manifestations of fatigue and the cortisol response to exercise was not related to the amount of circulating IL-6, but only to the activation of ACTH secretion.

Influence of the sample collection method on salivary interleukin–6 levels in resting and post-exercise conditions

“…Another interesting aspect of the exercise-triggered IL-6 increase is the high inter-individual variability of IL-6 peak values that was observed in the present study, as well as in previous reports (Minetto et al 2006;Ostrowski et al 1998). The biological reasons why athletes can have diVerent degrees of IL-6 increase after completing similar strenuous exercises begin to be uncovered: a recent and very interesting study showed the existence of an association between IL-1 gene variants and post-exercise IL-6 mRNA content in vastus lateralis biopsies collected before and after acute resistance exercise (Dennis et al 2004).…”

“…We observed that IL-6 peak levels occurred 1 h after the termination of the exercise: this delayed increase allows us to exclude that plasma volume changes played a role in determining the observed cytokine response. Moreover, post-exercise IL-6 change presented a dynamics similar to the previously described cytokine increase in response to isokinetic exercise (Croisier et al 1999;Minetto et al 2006). However, in these previous papers the IL-6 peak levels were higher with respect to the values we measured in response to isometric contractions: this observation suggests that the mode of muscle contraction must be considered as an important modulator factor of the contractionrelated IL-6 production.…”

Quimiossensibilidade durante exercício na insuficiência cardíaca: respostas ventilatórias, cronotrópicas e neurohormonais

“…As previously described, we observed in healthy individuals at rest an elevation of IL-6 levels with acute hypoxic stimulus 36,37 . Like was seen in our results, HF group had higher baseline IL-6 levels 38 , but we didn't observe at rest hypoxic response.…”

“…The physiological significance of IL-6 response to hypoxia remains unknown, once that IL-6 acts not as a mediator of inflammation or acute-phase protein response, since IL-1, TNFα and CRP remain unchanged. Two other possible actions have been suggested as an angiogenic effect plus a modulatory effect on erythropoietin production 37 .…”

“…The exercise has been described as a stressor with IL-6 increase, which was related to effort intensity and potentially justified by lactate levels, endothelial shear stress and muscle damage and less with catecholamine production 37,38 . In our study we supposed that despite IL-6 be repressed by beta-blocker action in HF group, when was added exercise stress to hypoxia, this blockade was insufficient and IL-6 course with huge increase 37 .…”