Is physical working capacity determined by optimal magnesium concentration?

Two lines of research originated in the mid-seventies; one attempted to gauge the effect of strenuous effort on serum magnesium concentration (S-Mg) and the second, the effect of S-Mg on the indices of physical working capacity. In apparently healthy trained young Israeli men, long-term studies of the effect of strenuous effort on S-Mg showed that after a moderately strenuous effort (70 km forced march), there was a decrease of S-Mg which became statistically significant after 72 h, whereas after a severely strenuous effort (120 km forced march), the decrease was biphasic, being significant after 1 h, with a second fall after 72 h. In repeated experiments, the decrease of S-Mg was found to persist over time parallel 1. Since chronic lowering of S-Mg signifies a concomitant lowering of intracellular Mg content, these findings showed that Mg deficiency was a sequel to strenuous effort. Studies of the effect of S-Mg on the indices of physical working capacity showed that: (1) S-Mg determines the maximal voluntary muscle contraction force (MVC); (2) S-Mg affects, among other things, the maximal aerobic capacity (VO2max). The estimated daily Mg intake in the Israeli population is inadequate and a widely prevalent marginal to overt Mg deficiency is found in apparently healthy Israelis. It is proposed that an optimal physical working capacity in the Israeli population will be achieved only under conditions of Mg saturation of metabolism. Studies to validate this hypothesis are under progress.