One week of magnesium supplementation lowers IL-6, muscle soreness and increases 1 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 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 hrs 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 hr, 1 hr and 24 hrs post TT. Muscle soreness was measured at the previous times plus 48 hrs and 72 hrs post. Glucose and lactate were measured during the TT. Results: Main effect of condition were detected for IL-6 (SUP: 1.36 ± 0.66 vs CON: 2.06 ± 1.14 pg/ml) (P < 0.05, η2 = 0.54), sIL-6R (SUP: 27615 ± 8446 vs CON: 24368 ± 7806 pg/ml) (P < 0.05, η2 = 0.41) and muscle soreness (P < 0.01, η2 = 0.67). Recovery of blood glucose and muscle soreness were enhanced in SUP post TT. There were no differences in glucose and lactate during the TT, or post measures of CK and maximal muscle force. Conclusion: Magnesium supplementation reduced the IL-6 response, enhanced recovery of blood glucose, and muscle soreness after strenuous exercise, but did not improve performance or functional measures of recovery