Dr. San-Millán is an Assistant Professor at the University of Colorado School of Medicine, Anschutz Medical Campus and an Associate Professor at the University of Colorado, Colorado Springs. He is an internationally renowned applied physiologist and has worked for the past 27 years for many professional teams and elite athletes around the world across multiple sports. He has also been a consultant in exercise physiology and sports medicine to international organizations such as the U.S. Olympic Committee and the International Cycling Union. He is a pioneer in new methodologies for monitoring athletes at the metabolic and physiological levels, including the invention, along with his colleague Dr. John Hill, of the first method for measuring skeletal muscle glycogen in a non-invasive manner using high-frequency ultrasound. He also developed the first methodology for measuring mitochondrial function during exercise. Dr. San-Millán's areas of research, clinical work, and interest include exercise metabolism, cancer metabolism, metabolic health, nutrition, sports performance, diabetes, and critical care. In the field of cancer research, Dr. San-Millan has recently demonstrated that lactate is an oncometabolite capable of regulating the expression of the main genes involved in breast cancer. He has also recently shown that lactate exposure disrupts cellular metabolism.