Interleukin-6 response to isokinetic exercise in elite athletes: relationships to adrenocortical function and to mechanical and myoelectric fatigue.
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.
Minetto
M A
MA
Divisione di Endocrinologia e Metabolismo, Dipartimento di Medicina Interna, Università di Torino, Torino, Italy. marcominetto@libero.it
Rainoldi
A
A
Gazzoni
M
M
Ganzit
G P
GP
Saba
L
L
Paccotti
P
P
D000302:Adrenal Cortex / Q000502:physiology*; D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography; D004594:Electrophysiology; D015444:Exercise / Q000502:physiology*; D006728:Hormones / Q000737:chemistry; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D015850:Interleukin-6 / Q000097:blood*; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D009211:Myoglobin / Q000378:metabolism; D010807:Physical Endurance / Q000502:physiology; D012463:Saliva / Q000737:chemistry; D013177:Sports / Q000502:physiology*
D006728:Hormones; D015850:Interleukin-6; D009211:Myoglobin; D019344:Lactic Acid; D006854:Hydrocortisone