| Aim: Magnesium supplementation has long been a popular method of improving athletic performance,however the mechanism in which magnesium enhances performance is not yet fully understood,Research has indicated magnesium may have role in increasing the availability of glucose during exercise in the peripheral systems and the central nervous systems,delaying the onset of muscular fatigue via reducing circulatory lactate levels,and potentially as an anti-inflammatory agent.Past research into magnesium supplementation has predominantly been based on rodent models,and in the few available human studies,results are challenging to interpret due to the lack of dosage standardisation.Therefore,further research is required to investigate magnesium as an ergogenic aid.Method: 6 male recreational endurance runners completed a double-blind crossover,with placebo,taking 500mg/day of magnesium for a 7-day period.During the study all participants were exposed to 3 conditions(magnesium,placebo and control).In the magnesium and placebo conditions participants kept magnesium intake below 260 mg per day,the control condition had no restriction on magnesium intake.Participants completed a 10 km time trial,at a gradient of-10%,on day 7 of supplementation,followed by 5 repetition maximum flexion and extension of the knee the day after the time trial.Pre,during and post time trial at every 2km stage,glucose,lactate concentrations and time taken were measured.On TT completion the time taken to complete the 10 km run was recorded.Immediately pre,post,1hr and24 h post time trial,circulating cytokine Interleukin 6(IL-6)was measured.Participants then had a 2-week washout period with no magnesium supplementation,then crossover.Results: The results of this study demonstrated that 500mg/day,over a 7-dayperiod,can reduce circulating IL-6 at rest,immediately,1h and 24 h post 10 km downhill time trial performance,when compared to the placebo condition on a restricted diet of <260mg of magnesium per day(P>0.05).In addition,a significant increase in IL-6 was observed across all conditions both immediately and 1h post10 km downhill time trial,when compared to baseline values(P<0.05).Furthermore,magnesium supplementation increased circulating glucose 1h and 24 h post 10 km downhill time trial in comparison to the placebo condition(P>0.05).In both the placebo and control conditions the average concentric extensors were observed to significantly reduce 24 h post time trial(P<0.05),however this was not present in the magnesium condition(P>0.05).There were no significant differences between 10 km downhill time trial performance between all conditions(P>0.05).Conclusion: The results of this study indicate that 500mg/day of magnesium,over a 7-day period,can reduce IL-6 concentrations at rest,immediately post,1h post and 24 h post 10 km downhill time trial performance.In addition,a significant increase in IL-6 was observed in all conditions immediately and 1h post 10 km downhill time trial performance,in comparison to the baseline values.Magnesium supplementation can increase circulating blood glucose levels as early as 1h and as late as 24 h post exercise,indicating that magnesium may be beneficial for the recovery process.Finally,magnesium has the potential to increase muscle function through various biological mechanisms.On this basis,it is possible that magnesium supplementation may benefit athletic performance when the main objective is the speed of recovery,rather than muscle adaptation. |
