Absence of effect of potassium-magnesium aspartate on physiologic responses to prolonged work in aerobically trained men.
The effects of oral administration of potassium and magnesium aspartate (K + Mg Asp) on physiologic responses to 90 min of treadmill walking at approximately 62% VO2 max were evaluated in seven healthy males (VO2 max = 59.5 ml X kg-1 X min-1). A total of 7.2 g of K + Mg Asp were administered to each subject during a 24 h period prior to work and compared to control and placebo trials. For control, placebo, and K + Mg Asp trials, no significant differences were observed in resting or exercise values for ventilation (VE), oxygen uptake (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (RO), heart rate (HR), or blood pressure (BP). In addition, there were no differences between the three trials for exercise-induced decreases in body weight and increases in rectal temperature, or for pre- and post-exercise alterations in serum lactic acid, creatine kinase, lactic dehydrogenase, and percentage change in plasma volume. The findings from this study indicate that oral ingestion of K+ Mg Asp prior to exercise had no effect on cardiorespiratory, hematologic, and metabolic responses to 90 min of work conducted at approximately 62% VO2 max.