The Circadian Physiology Program focuses on basic and applied aspects of human circadian biology. Our translational approach includes use of a range of techniques including epidemiology, field-based physiological studies and inpatient intensive physiological monitoring. We have a particular interest in human circadian photoreception and the effects of light on the circadian pacemaker and other non-image forming responses. Our studies include investigations of the effects of timing, duration, intensity and wavelength of light exposure on circadian resetting, melatonin suppression and the acute alerting effects of light. We also study visually impaired individuals under field and laboratory conditions to examine the effects of the severity and type of blindness on circadian photoreception, the periodicity of the circadian pacemaker and development of circadian rhythm sleep disorders. These basic studies have led to the development of novel therapeutic strategies to treat non-24-hour sleep wake disorder, Advanced- and Delayed Sleep Phase Syndrome with appropriately-timed melatonin administration in blind patients. We have also recently begun to examine the role of visual impairment on endocrinology and breast cancer risk in blind women.
With the Harvard Work Hours Health and Safety Group, we assess the impact of extended work hours on health and safety of workers and the public. Our studies include the development of interventions that reduce extended duration work hours, fatigue and medical errors in hospital residents, and the implementation of large-scale occupational fatigue management and sleep disorders screening programs in several police forces nationwide.