Smith, R. W., Chen, C-H., & Jang, J-T. (June 2, 2010). High magnesium intake effects on female athlete's metabolism after high intensity exercise. Presentation 1565 at the 2010 Annual Meeting of the American College of Sports Medicine, Baltimore, Maryland; June 2-5.

This study investigated the effects of a high-dose magnesium intake on metabolism after high intensity exercise in female track athletes (N = 7). Two tests consisting of a 600 m run at maximum speed with one day break between tests were conducted. In test one (T1) each athlete consumed eight ounces of water 30 minutes before the test. In test two (T2) each athlete consumed 400 mg of magnesium with eight ounces of water 30 minutes before the test. Blood samples were taken prior to the test and at 1, 3, 5, 7, 10, and 15 minutes after exercise for lactate, glucose, hematocrit, heart rate and ammonia analyses.

Lactate concentration after the magnesium test was significantly lower, as were glucose and ammonia. As for hematocrit and speed between the two test conditions, there were no significant differences.

Implication. It is well established that the main energy resource for anaerobic exercise is glycogen. High magnesium intake before exercise was shown to facilitate anaerobic glycolysis which in turn improved the metabolism. This effect may be due to enhanced PFK activation from the magnesium intake and the energy supply from the increased efficiency of glycogen use. [This study shows a definite physiological change that is unaccompanied by any performance change.]

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