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31.07.2015

Short-term magnesium supplementation boosts maximal strength

Magnesium supplementation makes you stronger, but the effect depends on how long you use it for. Lindsy Kass and Filipe Poeira of the University of Hertfordshire write in the Journal of the International Society of Sports Nutrition that only short periods of magnesium supplementation boost maximal strength. If you take magnesium for weeks on end it'll have no effect on your strength.

Magnesium
Meta studies suggest that magnesium supplementation reduce blood pressure by 2-4 points. [Eur J Clin Nutr. 2012 Apr;66(4):411-8.] Kass and Poeira published an exploratory in 2013 in which administration of magnesium during strength training sessions also had a positive effect on blood pressure. [J Sports Sci Med. 2013 Mar 1;12(1):144-50.]

The study that Kass and Poeira recently published in the Journal of the International Society of Sports Nutrition confirms the findings of the earlier study. But the researchers discovered another, and possibly even more interesting effect of magnesium supplementation.

Study
The researchers used a dozen athletes for their experiment. They gave half of them 300 mg magnesium in the form of magnesium citrate [Mg] daily for a week [Acute]. On another occasion this group was given a placebo for a week.

The other half took a magnesium supplement for four weeks [Chronic], and on another occasion was given a placebo for four weeks.

Results
The researchers got their subjects to do bench presses and discovered that 1 week of magnesium supplementation increased their maximal strength by 17 percent. This was a statistically significant effect. Magnesium supplementation that lasted four weeks had no effect, however.

The researchers suspect that magnesium supplementation has a performance enhancing effect, but that this effect disappears after a couple of days "perhaps due to saturation of Mg2+ within the blood or limitations to transporters."

The blood-pressure reducing effect of magnesium supplementation did continue throughout the longer-term supplementation.

Conclusion
"To conclude, from this study there appears to be no benefit in long term magnesium supplementation for those who have adequate dietary intake, but there are some benefits for taking an acute dose, particularly before intense exercise", the researchers wrote.

It's not clear to what extent the findings also apply to strength athletes. The subjects were not used to weight training and before they did the bench presses they'd already cycled 40 km.

Source:
J Int Soc Sports Nutr. 2015 Apr 24;12:19.

More:
Magnesium supplement helps you perform to the max despite lack of sleep 16.12.2011