Abstract. 17 male officer trainees (between 20 and 24 years of age) of the Theresan Military Academy in Wiener Neustadt (Austria) have been subjected to a standardized 2,400-m run; before and after the run, capillary blood samples for determination of pCO 2 , pO 2 , BE, Mg, and lactate were drawn and their heart rate was determined. On the next day, the candidates received 150 mg of Mg as an effervescent tablet after blood sampling, and 1 hour later, after another sampling, the same 2,400-m run as before was performed again with a consecutive sampling. It turned out that all parameters measured out of the samples before the run did not differ significantly, just as the samples after the run did not differ between Mg-treated and untreated subjects. However, Mg changes due to the run were much less uniform in Mg-treated subjects. Linear correlations, which developed significantly between ionized Mg, pO 2 , pCO 2 , BE, and lactate, as well as significant linear correlations between heart rate and lactate, and also between Mg and running time (our performance marker), were in fact always seen in untreated subjects but never in Mg-treated participants. We deduce that acute Mg application before sport does not enhance the more easily fluctuating ionized fraction, but enriches the protein- and complex-bound Mg fraction within the blood so that ionized Mg can be replenished from there, and only to a lesser degree from tissues, and limiting steps – characterized by linear relations between Mg and stress markers or between stress markers themselves – are abolished. By such an acute Mg application before sport, limiting steps brought about by Mg shortage are set aside by easily available Mg reserves in blood enriched by the preserved tissue Mg pool, all that opening out into significant influences upon effort and performance.
|ScienceOpen disciplines:||Endocrinology & Diabetes, General medicine, Medicine, Gastroenterology & Hepatology, Nutrition & Dietetics|
|Keywords:||acute Mg application, sport, bound fraction, preservation of reserves, Mg availability|