Research on the underlying pathophysiology of exercise-associated hyponatremia (EAH) showed dysregulation of arginine vasopresin to be the proximate cause. Novel treatments based in part on this finding have been incorporated into consensus statements as evidence-based standards of care. Research on cocaine and nicotine pharmacokinetics in human subjects has provided insights to guide the treatment of addiction to these substances. Discovery that cocaine causes a blood doping effect in human subjects accounts in part for 20 fold increase in risk for acute cardiac events in the hour after usage. Associate Professor of Medicine, Harvard Medical School.