The goal of Dr. Shea’s research is to understand the biological basis behind changes in disease severity across the day and night, and to understand the physiological and adverse health effects of shift work. For instance, Dr. Shea is determining whether cardiovascular changes across the day and night are caused by the body clock (the endogenous circadian pacemaker) or attributable to behaviors that occur on a regular daily basis, including the sleep/wake cycle. Understanding the biological basis of these physiological and pathophysiological changes across the day and night may provide an insight into the underlying cause of the disease and could lead to better therapy (e.g. appropriately timed medication to target specific phases of the body clock or to coincide with specific behaviors that cause vulnerability, such as exercise), and countermeasures aimed at reducing the adverse health effects of shift work.