title: Characterizing free-living light exposure using a wrist-worn light monitor.
abstract: It was the purpose of this study to pilot the use of a new wrist-worn light monitoring device to document that indoor lighting for a particular day-shift work environment could serve as the primary light exposure dosage in healthy free-living humans. Twelve employees of a local hospital volunteered to wear a wrist-worn light monitor during all waking hours for an entire workweek (Monday-Friday). Light data were analyzed (3-Factor RM ANOVA) for the dose of light exposure (minutes of exposure x light intensity) within six light intensity categories (< 1, 1-100, 101-200, 201-500, 501-1000, > 1000 1x) relative to time spent within their work environment and all other time of the day. The greatest dose of exposure occurred within the 201-500 1x range during the subjects' work shift. These data support the premise of others that long term exposure to dim indoor light intensities commonly experienced within a variety of work environments may serve as the primary entrainment factor for physiological and behavioral processes following a circadian rhythm.
authors.affiliation: Department of Health and Human Development, Montana State University, Bozeman 59717-3540, USA. dheil@montana.edu
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Heil
authors.forename: Susan R
authors.initials: SR
authors.lastname: Mathis
mesh_terms: D000328:Adult; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008029:Lighting; D008297:Male; D009009:Montana; D010564:Personnel, Hospital; D010789:Phototherapy; D010865:Pilot Projects; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation*; D017132:Workplace; D014953:Wrist