Therapeutic Strategies to Reduce Endothelial Ischemia-reperfusion Injury

The objective of this clinical trial is to better understand how lactate, a naturally occurring energy substance, can be used to lessen damage to the vascular system in adults with a high cardiovascular disease risk. The main questions it aims to answer are: 1. Does giving lactate intravenously reduce injury to the vascular system? 2. Does giving lactate intravenously together with blood flow occlusion - known as ischemic preconditioning, reduce vascular injury better than blood flow occlusion by itself? 3. How does lactate help the vascular system? Researchers will compare lactate to a placebo (a look-alike substance that contains no lactate) to see if lactate works to lessen vascular injury. Researchers will also compare lactate to blood flow occlusion to see which one is better at preventing vascular injury. Researchers will also compare lactate and blood flow occlusion together to see if combining them works better than either one alone. In one visit to the laboratory, participants will: Obtain a measurement of vascular health in an arm Be given liquid lactate, a liquid placebo, and/or arm blood flow occlusion Obtain a second measurement of vascular health in an arm.