Multi-wearable approach for monitoring diurnal light exposure and body rhythms in nightshift workers

Article Article scientifique Article Multi-wearable approach for monitoring diurnal light exposure and body rhythms in nightshift workers eng 2025-07 author Hartmeyer Steffen L 0000-0002-2813-2668 Laboratory of Integrated Performance in Design (LIPID), School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. author Phillips Nicholas Service of Endocrinology and Diabetology, Department of Medicine, Geneva University Hospitals, Geneva, Switzerland.,Laboratories of Neuroimmunology, Center for Research in Neuroscience and Service of Neurology, Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,Division of Thoracic and Endocrine Surgery, Department of Surgery, Geneva University Hospitals, Geneva, Switzerland.,Faculty of Medicine, Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland. 403969 author Jassil Friedrich Christie Bin 0000-0002-9721-7665 Service of Endocrinology and Diabetology, Department of Medicine, Geneva University Hospitals, Geneva, Switzerland.,Faculty of Medicine, Diabetes Centre, University of Geneva, Geneva, Switzerland. 429308 author Joris Celine Service of Endocrinology and Diabetology, Department of Medicine, Geneva University Hospitals, Geneva, Switzerland. 417732 author Dibner Charna 0000-0002-4188-803X Division of Thoracic and Endocrine Surgery, Department of Surgery, Geneva University Hospitals, Geneva, Switzerland.,Faculty of Medicine, Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland.,Faculty of Medicine, Diabetes Centre, University of Geneva, Geneva, Switzerland.,iGE3 Genomics Platform, Geneva, Switzerland. 583541 Département de chirurgie (CHIRU) author Collet Tinh-Hai 0000-0002-3243-1222 Service of Endocrinology and Diabetology, Department of Medicine, Geneva University Hospitals, Geneva, Switzerland.,Faculty of Medicine, Diabetes Centre, University of Geneva, Geneva, Switzerland. 935563 Département de médecine (DEMED) author Andersen Marilyne 0000-0001-8813-1184 Laboratory of Integrated Performance in Design (LIPID), School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. e70069 10.1111/apha.70069 40485643 1748-1708 https://onlinelibrary.wiley.com/doi/10.1111/apha.70069 Aim: As our understanding of light's impact on human health grows, studies examining light exposure and related health outcomes in everyday settings are increasingly important, particularly in high-risk groups like nightshift workers. Methods: In this observational study, we monitored personal light exposure and physiological functions in a large cohort of healthcare nightshift workers using a spectrally resolved light dosimeter and wearable body temperature, actigraphy, and electrocardiography sensors. Results: Our findings revealed a common occurrence of unfavorable light conditions during both shift types. During nightshift work, participants frequently experienced exposure to biologically potent cool-white LED lighting. On dayshifts, melanopic light levels often failed to meet recommended guidelines, with daylight as the primary source of bright light levels. Sleep duration, but not quality, significantly varied between shifts, with longer sleep before the first nightshift but shorter sleep on subsequent nights. Daytime and nighttime napping helped compensate for reduced sleep on nightshifts. Limited associations between light exposure and sleep were found, partially contradicting existing knowledge. Diurnal physiological and activity rhythms followed the change from day-active to night-active schedules; however, the change in physiological rhythms appeared partly dissociated from that of activity, suggesting a circadian modulation. Moreover, physiological functions exhibited bi-directional phase-shifts across consecutive nightshifts, which may have been mediated by differences in daytime light exposure before the first nightshift. Conclusion: By employing a multi-wearable approach including recent sensors, we provide new insights into the lighting environments experienced by nightshift workers and the potential impact of nightshift work and light exposure on endogenous circadian rhythms. Circadian Light Shiftwork Sleep Humans Circadian Rhythm / physiology Male Adult Female Middle Aged Sleep / physiology Wearable Electronic Devices Shift Work Schedule Actigraphy Lighting Body Temperature / physiology Occupational Exposure Dewey 612 Dewey 616 Dewey 617 Dewey 590 European Commission LIGHTCAP: Light, Cognition, Attention, Perception 860613 LIGHTCAP EU H2020 Swiss National Science Foundation Aligning the timing of eating and exercise with circadian rhythms for improved metabolic health 212559 CH Projects Swiss National Science Foundation a- and ß-cellular clocks: a network of functional outputs and their potential therapeutic applications for type 2 diabetes 219187 CH Projects 56 Département de médecine 221 57 Département de chirurgie 222 23 Institut de génétique et de génomique 0DH 134 Département de physiologie cellulaire et métabolisme 21C false 1386 Nutrition et chronobiologie 1038 913 Endocrinologie et horloge circadienne 948 Acta physiologica 241 7 9977a5c2-b71d-40c4-8205-7c36d6ddf9f4 Article (Published version) Public Hartmeyer-Acta_Physiol.-2025-Multi-.pdf 2022024 application/pdf CC BY-NC-ND-4.0 04e315ce26f9089091e4ce63979b15d60dd4a15466af9aca9cca6044783e8738 a9906d7d-98f3-403b-989e-a955456b54fa Article (Accepted version) Public OPTI-SHIFT_Accepted_manuscript.pdf 2207402 application/pdf Restricted 2026-08-01 71c526a817bcb918c21f133a9cedcbecb32316e9f8d009705b079082ee00284c openAccess Faculté de médecine / Section de médecine clinique / Département de médecine Faculté de médecine / Section de médecine clinique / Département de chirurgie Centres et instituts / Institut de génétique et de génomique Faculté de médecine / Section de médecine fondamentale / Département de physiologie cellulaire et métabolisme

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Multi-wearable approach for monitoring diurnal light exposure and body rhythms in nightshift workers	Acta physiologica			2025	75	289

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