Observations on serum and red blood cell magnesium changes in treadmill exercise-induced cardiac ischemia.

To evaluate changes in magnesium levels with treadmill exercise-induced coronary insufficiency, 59 consecutive patients were studied. In addition to electrocardiographic monitoring, hematocrit, total protein, whole blood, serum and red blood cell magnesium determinations were made before and after exercise testing. Fifteen patients had positive exercise test, 18 did not complete, and 26 had negative exercise test. There was no significant difference in the serum and red blood cell magnesium on the basis of stress test results for ischemia. Although whole blood magnesium, hematocrit, and total proteins increased (P less than .05) in both groups, we did not find a significant change in magnesium homeostasis.