 ROV experiments: After control single forearm muscle contractions, subjects will repeat single contractions under conditions of K channel inhibition, and again under K channel plus nitric oxide and prostaglandin inhibition. This last phase of the study is aimed at testing acute compensatoryredundant vasodilator mechanisms. This trial consists of three sets of 6 singular muscle contractions three at 30, three at 60 of maximal effort, each contraction lasting less than 3 seconds with 90s rest in between. These single contractions evoke a robust 100-600 increase and rapid 3-6 heart beats post contraction increase in blood flow that returns to normal typically in about 30 seconds. This rapid and robust response is why these single muscle contractions are termed Rapid Onset Vasodilation. 3 minutes of rest before each trial will allow for baseline measurements and loading of inhibitors of K mediated vasodilation. During this 3 min, subjects will perform a single contraction at 15, 30, and 45s of the 3-min loadingresting period to facilitate delivery of the drug to the active tissues this adds an additional 18 contractions. The first experimental set of single contractions will be completed without drugs saline control. Next, an ATP infusion no exercise will also be used to test the pharmacological efficacy of subsequent inhibitor BaCl2. The first ATP infusion will be performed without other drugs. Following this, a second set of single contractions will be conducted with infusion of BaCl2. This is then followed by a second ATP infusion to determine the efficacy of BaCl2. The final set of single contractions will start and be performed with simultaneous infusion of all three inhibitors BaCl2, L-NMMA, and Ketorolac. This last phase of the study is aimed at testing acute compensatoryredundant vasodilator mechanisms. ROV exercise studies will be 4 hours 1 hour set up and 3 hours experimental procedures. The ROV protocol is further described here: 