title: Magnesium homeostasis during high-intensity anaerobic exercise in men.
abstract: This study was conducted to determine whether short-term, high-intensity anaerobic exercise alters Mg homeostasis. Thirteen men performed intermittent bouts of treadmill running at 90% of their predetermined maximum O2 uptake until exhaustion on one occasion during a week in which all men were consuming a standard diet (115 mg Mg/1,000 kcal). Plasma and erythrocyte Mg concentrations and peripheral blood mononuclear cell Mg content were measured before and after the exercise. Complete 24-h urine collections were obtained on control days, on the day of exercise, and on the day after exercise. Exercise induced a transient but significant decrease in plasma Mg content (-6.8%; P less than 0.01); over 85% of the loss could be accounted for by a shift to the erythrocytes. Significant increases in urinary excretion of Mg were observed on the day of exercise (131.5 +/- 6.8 mg/day) compared with control days (108 +/- 6.6 mg/day), with the percent increase correlating with postexercise blood lactate concentration (r = 0.68; P less than 0.01) and oxygen consumption during recovery (r = 0.84; P less than 0.001). The data indicate that high-intensity anaerobic exercise induces intercompartmental Mg shifts in blood that return to preexercise values within 2 h and urinary losses on the day of exercise that return to base line the day after exercise. It is postulated that the exercise-induced increase in Mg excretion may depend on the intensity of the exercise, and the relative contribution of anaerobic metabolism to the total energy expended during exercise.
mesh_terms: D000328:Adult; D000693:Anaerobiosis; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis; D006706:Homeostasis; D006801:Humans; D008274:Magnesium / Q000097:blood / Q000378:metabolism* / Q000652:urine; D008297:Male; D008660:Metabolism; D009000:Monocytes / Q000378:metabolism; D009994:Osmolar Concentration; D010101:Oxygen Consumption; D005082:Physical Exertion
chemical_list: D006454:Hemoglobins; D008274:Magnesium