Absence of Effect of Potassium-Magnesium Aspartate on Physiologic Responses to Prolonged Work in Aerobically Trained Men

Abstract The effects of oral administration of potassium and magnesium aspartate (K + Mg Asp) on physiologic responses to 90 min of treadmill walking at ∼62% VO 2 max were evaluated in seven healthy males (VO 2 max = 59.5 ml·kg -1 ·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 (V E ), oxygen uptake (VO 2 ), carbon dioxide production (VCO 2 ), 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 affect on cardiorespiratory, hematologic, and metabolic responses to 90 min of work conducted at ∼62% V̇O 2 max.