Next Article in Journal
Comparing the Effects of FIFO/DIDO Workers Being Home versus Away on Sleep and Loneliness for Partners of Australian Mining Workers
Previous Article in Journal
Lucid Dreaming and the Feeling of Being Refreshed in the Morning: A Diary Study
Open AccessOpinion

The Role of Daylight for Humans: Gaps in Current Knowledge

Sleep/Wake Research Centre, Massey University Wellington, Wellington 6021, New Zealand
Centre for Chronobiology, Psychiatric Hospital of the University of Basel, 4002 Basel, Switzerland
Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, 4002 Basel, Switzerland
Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
Faculty for Health and Social Affairs, University of Applied Sciences for Economics and Management (FOM), 45141 Essen, Germany
SynOpus, 44789 Bochum, Germany
Psychiatric Center Copenhagen, University of Copenhagen, Rigshospitalet, 2100 Copenhagen, Denmark
Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA
Division of Endocrinology, Metabolism and Diabetes, University of Colorado, Aurora, CO 80045, USA
Departments of Radiation Sciences and Molecular Biology, Umeå University, 901 87 Umeå, Sweden
Wallenberg Centre for Molecular Medicine (WCMM), Umeå University, 901 87 Umeå, Sweden
Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
Author to whom correspondence should be addressed.
Clocks & Sleep 2020, 2(1), 61-85;
Received: 31 October 2019 / Revised: 20 February 2020 / Accepted: 21 February 2020 / Published: 28 February 2020
(This article belongs to the Section Clocks & Sleep and Zeitgebers (Light))
Daylight stems solely from direct, scattered and reflected sunlight, and undergoes dynamic changes in irradiance and spectral power composition due to latitude, time of day, time of year and the nature of the physical environment (reflections, buildings and vegetation). Humans and their ancestors evolved under these natural day/night cycles over millions of years. Electric light, a relatively recent invention, interacts and competes with the natural light–dark cycle to impact human biology. What are the consequences of living in industrialised urban areas with much less daylight and more use of electric light, throughout the day (and at night), on general health and quality of life? In this workshop report, we have classified key gaps of knowledge in daylight research into three main groups: (I) uncertainty as to daylight quantity and quality needed for “optimal” physiological and psychological functioning, (II) lack of consensus on practical measurement and assessment methods and tools for monitoring real (day) light exposure across multiple time scales, and (III) insufficient integration and exchange of daylight knowledge bases from different disciplines. Crucial short and long-term objectives to fill these gaps are proposed. View Full-Text
Keywords: natural light; spectrum; twilight; circadian rhythms; melatonin; entrainment; health; sleep; alertness; mood natural light; spectrum; twilight; circadian rhythms; melatonin; entrainment; health; sleep; alertness; mood
Show Figures

Figure 1

MDPI and ACS Style

Münch, M.; Wirz-Justice, A.; Brown, S.A.; Kantermann, T.; Martiny, K.; Stefani, O.; Vetter, C.; Wright, K.P., Jr.; Wulff, K.; Skene, D.J. The Role of Daylight for Humans: Gaps in Current Knowledge. Clocks & Sleep 2020, 2, 61-85.

Show more citation formats Show less citations formats

Article Access Map by Country/Region

Back to TopTop