Studies
Independent research and documents on the effects of light on humans
We present studies from scientific institutions around the world and results from renowned laboratories and workplaces dealing with the effects of light on the body.
✓ Overall health
Disruption of circadian rhythms has been identified by the World Health Organization (WHO) as an independent risk factor for cancer. A paper by American scientists outlines the main regulatory functions of the circadian rhythm and its relevance to the development and treatment of cancer.
| Title: |
Cancer and the Circadian Clock |
| Author: | Ayesha A. Shafi, Karen E. Knudsen Thomas Jefferson University, Philadelphia, Pennsylvania |
| Date: | 1. August 2019 |
✓ Overall health
A UK university study has confirmed that photobiomodulation with 670 nm red light reduces fluctuations in blood glucose levels (glycaemia). Photobiomodulation light therapy thus serves as an effective preventive measure against the development of diabetes.
| Title: |
Light stimulation of mitochondria reduces blood glucose levels |
| Author: | Michael B. Powner, Glen Jeffery Department of Optometry and Visual Science, Centre for Applied Vision Research, School of Health and Psychological Sciences, City, University of London, London, UK Department of Visual Neuroscience, UCL Institute of Ophthalmology, University College London, London, UK |
| Date: | 21. January 2024 |
✓ Mood
A study by a team of Swiss, Japanese and Georgian researchers has shown that LED lighting with high melanopic efficiency and a spectral profile mimicking that of the sun improves visual comfort, mood, alertness and sleep compared to conventional LED lighting.
| Title: |
Effect of LED daylight on visual comfort, melatonin, mood, waking performance and sleep |
| Author: | C Cajochen PhD, M Freyburger PhD, T Basishvili PhD, C Garbazza MD, F Rudzik MS, C Renz FND, K Kobayashi MS, Y Shirakawa MS, O Stefani PhD, and J Weibel MS Psychiatric Hospital of the University of Basel, Switzerland Ilia State University, Tbilisi, Georgia Development and Engineering Department, Yokohama-City, Japan |
| Date: | 11. January 2019 |
✓ Mood
A study by a Dutch university has confirmed the effect of light on mental health, well-being and vitality, as well as on stress.
| Title: |
Salutogenic Effects of the Environment: Review of Health Protective Effects of Nature and Daylight |
| Author: | Femke Beute and Yvonne A.W. de Kort Eindhoven University of Technology, The Netherlands |
| Date: | 21. November 2013 |
✓ Sleep
Work by a University of Oregon research team describes sleep disturbances in high school students due to lack of quality light in classrooms.
| Title: |
Promoting adolescent sleep and circadian function: A narrative review on the importance of daylight access in schools |
| Author: | Sojeong Kim & Melynda D. Casement Department of Psychology, University of Oregon, Eugene, Oregon, USA |
| Date: | 14. April 2024 |
✓ Sleep
University of Texas analysis of existing research demonstrates that sleep and circadian dysfunction associated with unnatural light exposure significantly contribute to the development of a number of psychiatric disorders
| Title: |
The sleep-circadian interface: a window into mental disorders |
| Author: | N. Meyer, R. Lok, C. Schmidt, S. D. Kyle, C. McClung, C. Cajochen, F.A.J.L. Scheer, M.W. Jones, S.L. Chellappa The University of Texas Southwestern Medical Center, Dallas |
| Date: | 23. February 2024 |
✓ Eyes
A study by Beijing University showed that light sources with full spectral composition caused significantly less damage to the retina and photoreceptors compared to conventional LEDs.
| Title: |
More light components and less light damage on rats’ eyes: evidence for the photobiomodulation and spectral opponency |
| Author: | Jingxin Nie, Ningda Xu, Zhizhong Chen, Lvzhen Huang, Fei Jiao, Yiyong Chen, Zuojian Pan, Chuhan Deng, Haodong Zhang, Boyan Dong, Jiarui Li, Tianchang Tao, Xiangning Kang, Weihua Chen, Qi Wang, Yuzhen Tong, Mingwei Zhao, Guoyi Zhang, Bo Shen Peking University |
| Date: | 7. December 2022 |
✓ Productivity
A US study has shown that adjusting the amount of daylight and view improves the performance of office workers.
| Title: |
Windows and Offices: A Study of Office Worker Performance and the Indoor Environment |
| Author: | Lisa Heschong California Energy Commission |
| Date: | 20. October 2003 |
✓ Mood
A summary of several scientific papers describes how dopamine, a neurotransmitter associated with the regulation of mood and motivation, is linked to the functioning of circadian rhythms that are influenced by light exposure. Disrupting these rhythms with inappropriate lighting can also negatively affect mood.
| Title: |
Dopamine and its role in circadian rhythm, or is it the other way around? |
| Author: | Mgr. Tereza Ulrichová, Spectrasol |
| Date: | 22. April 2024 |
✓ Productivity
The National Institute of Mental Health of the Czech Republic, in collaboration with the Third Medical Faculty of Charles University, states that the blue component of the light spectrum improves cognitive function and increases attention (the procognitive effect), but at the same time suppresses the secretion of melatonin for quality sleep if a person is exposed to it in the evening and at night.
| Title: |
Effects of blue light on the circadian system, sleep and cognitive performance |
| Author: | Michal Šmotek, Jana Kopřivová, Peter Šóš National Institute of Mental Health, Klecany Charles University in Prague, Third Faculty of Medicine |
| Date: | 26. October 2015 |
✓ Overall health
A US-Australian research team examined the work of world experts in the field of circadian rhythms and came to a broad scientific consensus on the effect of light on the human body. They also mention the state of the electric lighting market and recommend changes to the standards.
| Title: |
Lights Should Support Circadian Rhythms: Evidence-Based Scientific Consensus |
| Author: | Martin Moore-Ede, David E. Blask, Sean W. Cain, Anneke Heitmann, Randy J. Nelson Circadian Light Research Center Tulane University School of Medicine Monash University Circadian Light Research Center West Virginia University |
| Date: | 19. January 2023 |
✓ Overall health
In the article, Chinese experts present the current scientific knowledge on how circadian rhythms regulate the immune system at the molecular, cellular and physiological levels, thereby contributing to homeostasis and disease resistance.
| Title: |
Circadian rhythm regulation in the immune system |
| Author: | Jun Ding, Pengyu Chen, Chunjian Qi Nanjing Medical University, China |
| Date: | 19. December 2023 |
