{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T17:48:00Z","timestamp":1791395280116,"version":"4.3.3"},"reference-count":32,"publisher":"American Society for Clinical Investigation","issue":"7","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2017,4,6]]},"abstract":"\n BACKGROUND.<\/jats:bold>\n In humans, a single light exposure of 12 minutes and multiple-millisecond light exposures can shift the phase of the circadian pacemaker. We investigated the response of the human circadian pacemaker to a single 15-second or 2-minute light pulse administered during the biological night.\n <\/jats:p>\n \n METHODS.<\/jats:bold>\n Twenty-six healthy individuals participated in a 9-day inpatient protocol that included assessment of dim light melatonin onset time (DLMO time) before and after exposure to a single 15-second (\n n<\/jats:italic>\n = 8) or 2-minute (\n n<\/jats:italic>\n = 12) pulse of bright light (9,500 lux; 4,100 K fluorescent) or control background dim light (<3 lux;\n n<\/jats:italic>\n = 6). Phase shifts were calculated as the difference in clock time between the two phase estimates.\n <\/jats:p>\n \n RESULTS.<\/jats:bold>\n Both 15-second and 2-minute exposures induced phase delay shifts [median (\u00b1 SD)] of \u201334.8 \u00b1 47.2 minutes and \u201345.4 \u00b1 28.4 minutes, respectively, that were significantly (\n P<\/jats:italic>\n = 0.04) greater than the control condition (advance shift: +22.3 \u00b1 51.3 minutes) but were not significantly different from each other. Comparisons with historic data collected under the same conditions confirmed a nonlinear relationship between exposure duration and the magnitude of phase shift.\n <\/jats:p>\n \n CONCLUSIONS.<\/jats:bold>\n Our results underscore the exquisite sensitivity of the human pacemaker to even short-duration single exposures to light. These findings may have real-world implications for circadian disruption induced by exposure to brief light stimuli at night.\n <\/jats:p>\n \n TRIAL REGISTRATION.<\/jats:bold>\n The study was registered as a clinical trial on www.clinicaltrials.org, NCT #01330992.\n <\/jats:p>\n \n FUNDING.<\/jats:bold>\n Funding for this study was provided by NSBRI HFP02802 and NIH P01-AG09975, R01-HL114088 (EBK), RC2-HL101340-0 (EBK, SWL, SAR, REK), K02-HD045459 (EBK), K24-HL105664 (EBK), T32-HL07901 (MSH, SAR), HL094654 (CAC), and AG044416 (JFD). The project described was supported by NIH grant 1UL1 TR001102-01, 8UL1TR000170-05, UL1 RR 025758, Harvard Clinical and Translational Science Center, from the National Center for Advancing Translational Science.\n <\/jats:p>","DOI":"10.1172\/jci.insight.89494","type":"journal-article","created":{"date-parts":[[2017,4,6]],"date-time":"2017-04-06T22:24:53Z","timestamp":1491517493000},"source":"Crossref","is-referenced-by-count":58,"title":["Circadian phase resetting by a single short-duration light exposure"],"prefix":"10.1172","volume":"2","author":[{"given":"Shadab A.","family":"Rahman","sequence":"first","affiliation":[{"name":"Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women\u2019s Hospital, Boston, Massachusetts, USA."},{"name":"Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Melissa A.","family":"St. Hilaire","sequence":"additional","affiliation":[{"name":"Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women\u2019s Hospital, Boston, Massachusetts, USA."},{"name":"Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anne-Marie","family":"Chang","sequence":"additional","affiliation":[{"name":"Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women\u2019s Hospital, Boston, Massachusetts, USA."},{"name":"Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nayantara","family":"Santhi","sequence":"additional","affiliation":[{"name":"Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women\u2019s Hospital, Boston, Massachusetts, USA."},{"name":"Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA."},{"name":"Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeanne F.","family":"Duffy","sequence":"additional","affiliation":[{"name":"Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women\u2019s Hospital, Boston, Massachusetts, USA."},{"name":"Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard E.","family":"Kronauer","sequence":"additional","affiliation":[{"name":"Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA."},{"name":"School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, USA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charles 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