One week of magnesium supplementation lowers IL-6, muscle soreness and increases post-exercise blood glucose in response to downhill running

Purpose Magnesium supplementation modulates glucose metabolism and inflammation, which could influence exercise performance and recovery. This study investigated the effect of magnesium intake on physiological responses and performance during eccentric exercise and recovery. Methods Nine male recreational runners completed a counterbalanced, double-blind, placebo-controlled, cross-over study, registered at ClinicalTrial.gov. Participants consumed low magnesium diets and were supplemented with 500 mg/day of magnesium (SUP) or placebo (CON) for 7 days prior to a 10 km downhill (− 10%) running time trial (TT), separated by a 2-week washout period. At baseline and 24 h post-TT, maximal muscle force was measured. Interleukin-6 (IL-6), soluble interleukin-6 receptor (sIL-6R) and creatine kinase (CK) were measured at rest, 0 h, 1 h and 24 h post-TT. Muscle soreness was measured at the previous times plus 48 h and 72 h post. Glucose and lactate were measured during the TT. Results The main effect of condition was detected for IL-6 (SUP: 1.36 ± 0.66 vs CON: 2.06 ± 1.14 pg/ml) ( P