OccHealthSci Clinical Research

Faculty in OccHealthSci study how work and stress affects the body and the mind. We categorize this as “clinical research” as we generally make measurements in human volunteers in a research laboratory or by using ambulatory techniques in the homes or work environments of the volunteers. This research aims to understand the physiological changes induced by both the physical demands and psychological stresses that are commonly experienced in many occupations.

Given the preponderance of shift work, a particular focus is understanding how the body clock regulates our physiology and how this system is disturbed by night shift work and affects health. Studies performed in volunteers staying in our clinical research laboratories over numerous consecutive days include examining the effects of time of day on appetite, mood, cognitive function and the cardiovascular system. For instance, we are studying the cardiovascular changes across the day and night that are caused by the body clock and how these effects may be involved in the morning increase in adverse cardiovascular events, including heart attacks, stroke and sudden cardiac death. Other studies are examining how a sedentary lifestyle – which is typical of many work situations - affects vascular physiology and cardiovascular risk markers.

Similar studies are being performed outside the laboratory include examining the sleep, alertness, cognitive performance and cardiovascular health of firefighters whose work involves physical and psychological stresses, very long shifts, and disturbed sleep. Analogous studies are also being performed in bus drivers and call-center operatives.

We are also examining how commonly used behaviors including exercise, or commonly used substances such as Vitamin C supplements or cannabis can affect sleep, cognitive performance and cardiovascular physiology. This research is leading to a better understanding of the biological basis of physiological and pathophysiological changes across the day and night that could lead to countermeasures aimed at reducing the adverse health effects of shift work or other occupational stresses.

Clinical Science Faculty

Nicole Bowles, PhD,
Assistant Professor
Bowles Lab

Steven A. Shea, PhD,
Professor and Director

Shea Lab

Matthew Butler, PhD,
Associate Professor

Butler Clock Physiology Lab

Saurabh S. Thosar, PhD, MS, OTR/L,
Assistant Professor

Thosar Lab

Ryan Olson, PhD,
Professor and Co-Director OHWC

Ryan Olson Lab

Affiliate Faculty

Jonathan S. Emens MD, FABSM,
Associate Professor of Psychiatry,


Brad Wipfli, PhD,
Assistant Professor,
OHSU-PSU School of Public Health


Miranda Lim, MD, PhD,
Associate Professor of Neurology, OHSU,
VA Portland Health Care System

Miranda Lim Lab

Andrew McHill, PhD,
Assistant Professor, School of Nursing, OHSU

McHill Lab