The Effect of Calcium Clamp on Serum Ionized Calcium Levels

We developed a calcium clamp where we would infuse calcium gluconate intravenously. We wanted to get an increase of about 0.2 milligrams per deciliter, just so we had a cushion. And then using this handheld point of care device that we had, we measured serum serum ionized calcium every five minutes. They both peaked at about the same time. PTH peaked about 15 minutes after exercise and then came, screaming back down to baseline by an hour after exercise. CTX increased about one hour after exercise, but it plateaued. At four hours after exercise, there was no hint that it was starting to come back down.