Healthy woman undergoing glucose challenge (IMAGE) University of California - Berkeley Caption A volunteer is monitored after being given a large dose of glucose to determine how well people switch from fat to carbohydrate metabolism as they age. In the tests at UC Berkeley, subjects had their blood monitored for labeled lactate and glucose, underwent periodic blood sampling, and had their breath monitored for oxygen and carbon dioxide. Credit Robert Leija, UC Berkeley Usage Restrictions none License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.