Age effects on interleukin-6 and interleukin-1 beta responses to enduranceexercise in patients with neuromuscular diseases

Plasma IL-6 before and 20 min after prolonged muscular exercise for 20 min at the individual aerobic/anaerobic threshold was analyzed in patients with neuromuscular diseases and in controls. Patients were assigned to the foll owing diagnostic categories: Controls (n = 18); amyotrophic lateral scleros is (n = 7); peripheral neuropathy (n = 6); muscular dystrophy (n = 13); mit ochondriopathy (n = 3); myopathy (others) (n = 3); inflammatory myopathy (n = 6); mononeuropathy (n = 4). The concentrations of IL-6 before exercise w ere 5.55 +/- 0.94 pg/ml, and 6.52 +/- 0.97 pg/ml after exercise (P = 0.0001 ). We introduced the independent variables age, sex and diagnostic category into a stepwise multiple linear regression model. Age emerged as a signifi cant predictor of the IL-6 ratio (IL-6 post exercise/IL-6 before exercise). The regression equation was: IL-6 ratio = 0.87 +/- 0.009 x age (years), R = 0.33, P < 0.01, simple linear regression model. All IL-1 beta concentrati ons were below the sensitivity of the assay (5 pg/ml). Concerning patients with neuromuscular diseases, the age associated increased IL-6 release afte r exercise could mean additional muscle damage. (C) 1999 Elsevier Science I reland Ltd. All rights reserved.