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Petrowski K, Mekschrat L, Bührer S, Siepmann M, Albus C, Schmalbach B. Effects of Post-awakening Light Exposure on Heart Rate Variability in Healthy Male Individuals. Appl Psychophysiol Biofeedback 2023; 48:311-321. [PMID: 36971985 PMCID: PMC10412670 DOI: 10.1007/s10484-023-09581-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2023] [Indexed: 03/29/2023]
Abstract
Light-induced effects on the autonomic nervous system (ANS) are assumed to be mediated by retinal projections to the hypothalamic suprachiasmatic nucleus (SCN) via different routes. Light information for the circadian system is detected by a subset of intrinsically photosensitive retinal ganglion cells (ipRGCs), however, inconsistency exists in research concerning the effects of light exposure on heart rate variability (HRV). Two within-subject experiments were conducted in a standardized sleep laboratory to investigate effects of light intensity (study I, n = 29: 2 days dim vs. bright light) and spectral composition (study II, n = 24: 3 days using red vs. blue vs. green light) on HRV parameters (RMSSD, LF, HF-HRV, LF/HF ratio). Light exposure was conducted for one-hour in the post-awakening phase at 5:00 AM. Results revealed no significant light intensity effect comparing dim light versus bright white light on HRV parameters. Light color of different wavelengths significantly influenced all HRV parameters except the low frequency, with moderate to large effect sizes. RMSSD values were elevated for all three colors compared to norm values, indicating stronger parasympathetic activation. LED light of different spectral compositions demonstrated bidirectional effects on spectral components of the HRV. Red light decreased the LF/HF ratio within 30 min, whereas with blue light, LF/HF ratio consistently increased across 40 min of light exposure.
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Affiliation(s)
- Katja Petrowski
- Medical Psychology & Medical Sociology, University Medical Center of the Johannes Gutenberg - University Mainz, University Medicine Mainz, Duesbergweg 6, 55128, Mainz, Germany.
| | - Liza Mekschrat
- Medical Psychology & Medical Sociology, University Medical Center of the Johannes Gutenberg - University Mainz, University Medicine Mainz, Duesbergweg 6, 55128, Mainz, Germany
| | - Stefan Bührer
- Medical Psychology & Medical Sociology, University Medical Center of the Johannes Gutenberg - University Mainz, University Medicine Mainz, Duesbergweg 6, 55128, Mainz, Germany
| | - Martin Siepmann
- Department of Psychotherapy and Psychosomatic Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Christian Albus
- Department of Psychosomatic Medicine and Psychotherapy, University Medical Center of University Cologne, Cologne, Germany
| | - Bjarne Schmalbach
- Medical Psychology & Medical Sociology, University Medical Center of the Johannes Gutenberg - University Mainz, University Medicine Mainz, Duesbergweg 6, 55128, Mainz, Germany
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Antemie RG, Samoilă OC, Clichici SV. Blue Light-Ocular and Systemic Damaging Effects: A Narrative Review. Int J Mol Sci 2023; 24:ijms24065998. [PMID: 36983068 PMCID: PMC10052719 DOI: 10.3390/ijms24065998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/13/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Light is a fundamental aspect of our lives, being involved in the regulation of numerous processes in our body. While blue light has always existed in nature, with the ever-growing number of electronic devices that make use of short wavelength (blue) light, the human retina has seen increased exposure to it. Because it is at the high-energy end of the visible spectrum, many authors have investigated the theoretical harmful effects that it poses to the human retina and, more recently, the human body, given the discovery and characterization of the intrinsically photosensitive retinal ganglion cells. Many approaches have been explored, with the focus shifting throughout the years from examining classic ophthalmological parameters, such as visual acuity, and contrast sensitivity to more complex ones seen on electrophysiological assays and optical coherence tomographies. The current study aims to gather the most recent relevant data, reveal encountered pitfalls, and suggest future directions for studies regarding local and/or systemic effects of blue light retinal exposures.
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Affiliation(s)
- Răzvan-Geo Antemie
- Department of Physiology, Faculty of Medicine, "Iuliu Haţieganu" University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania
| | - Ovidiu Ciprian Samoilă
- Department of Ophthalmology, Faculty of Medicine, "Iuliu Hatieganu" University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania
| | - Simona Valeria Clichici
- Department of Physiology, Faculty of Medicine, "Iuliu Haţieganu" University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania
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Danilenko KV. Objective Measures of Immediate “Energizing” Effect of Light: Studies Review and Data Analysis. Clocks Sleep 2022; 4:475-496. [PMID: 36278531 PMCID: PMC9589941 DOI: 10.3390/clockssleep4040038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/18/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022] Open
Abstract
While the energizing effect of light has been known since the early years of light therapy, its reliable detection using objective measures is still not well-established. This review aims to ascertain the immediate energizing effect of light and determine its best indicators. Sixty-four articles published before July 2022 were included in the review. The articles described 72 (sub-)studies performed in healthy individuals. Fourteen measures were analyzed. The analysis showed that light causes an energizing effect that can be best documented by measuring core (rectal) body temperature: the proportion of the studies revealing increasing, unchanging, and decreasing rectal temperature was 13/6/1. The second most suitable indicator was heart rate (10/22/1), which showed concordant changes with rectal temperature (a trend, seven mutual studies). There is no evidence from the reviewed articles that oxygen consumption, skin conductance, blood pressure, heart rate variability, non-rectal inner temperature (combined digestive, tympanic, and oral), skin temperature, or cortisol levels can provide light effect detection. Four other measures were found to be unsuitable as well but with less certainty due to the low number of studies (≤3): skin blood flow, noradrenaline, salivary alpha-amylase, and thyroid-stimulating hormone levels. On the other hand, light exposure had a noticeable effect on sympathetic nerve activity measured using microneurography; however, this measure can be accepted as a marker only tentatively as it was employed in a single study. The analysis took into account three factors—study limitation in design/analysis, use of light in day- or nighttime, and relative brightness of the light stimulus—that were found to significantly influence some of the analyzed variables. The review indicates that the energizing effect of light in humans can be reliably detected using rectal temperature and heart rate.
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Luo X, Ru T, Chen Q, Li Y, Chen Y, Zhou G. Influence of daytime blue-enriched bright light on heart rate variability in healthy subjects. Chronobiol Int 2022; 39:826-835. [PMID: 35209793 DOI: 10.1080/07420528.2022.2040526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Heart rate variability (HRV), the indicator of the autonomic nervous system-induced modulation of heart rate, is a focal topic in psychophysiological research. The effect of indoor light on HRV may be related to various psychophysiological functions. The current study (N = 20) examined the response of the autonomic nervous system (ANS) to bright vs. dim blue-enriched light (1200 lx or 200 lx at eye level, 6500 K) exposure for five hours in the afternoon among healthy young adults. The results revealed a significant main effect of light condition on the time-domain indicators, with the significantly higher HRV (SDNN and RMSSD) under 200 lx versus 1200 lx condition, and the same case was revealed for the standard deviations of the Poincaré plot in non-linear effects. Conversely, no significant effects were revealed for the frequency- domain indicators of HRV measured with the subjects' eyes open. These findings suggested that the autonomic nervous system modulation of HRV was stronger under bright light conditions.
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Affiliation(s)
- Xue Luo
- School of Psychology, South China Normal University, Guangzhou, China
| | - Taotao Ru
- Lab of Light and Physiopsychological Health, National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, China
| | - Qingwei Chen
- Lab of Light and Physiopsychological Health, National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, China
| | - Yun Li
- School of Psychology, South China Normal University, Guangzhou, China
| | - Yuping Chen
- School of Psychology, South China Normal University, Guangzhou, China.,Lab of Light and Physiopsychological Health, National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, China
| | - Guofu Zhou
- Lab of Light and Physiopsychological Health, National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, China
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Effects on Heart Rate Variability of Stress Level Responses to the Properties of Indoor Environmental Colors: A Preliminary Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18179136. [PMID: 34501724 PMCID: PMC8430831 DOI: 10.3390/ijerph18179136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 08/26/2021] [Accepted: 08/27/2021] [Indexed: 12/24/2022]
Abstract
Color is the most potent stimulating factor affecting human vision, and the environmental color of an indoor space is a spatial component that affects the environmental stress level. As one of the methods of assessing the physiological response of the autonomic nervous system that influences stress, heart rate variability (HRV) has been utilized as a tool for measuring the user’s stress response in color environments. This study aims to identify the effects of the changes of hue, brightness, and saturation in environmental colors on the HRV of two groups with different stress levels—the stress potential group (n = 15) and the healthy group (n = 12)—based on their stress level indicated by the Psychosocial Well-being Index (PWI). The ln(LF), ln(HF), and RMSSD values collected during the subjects’ exposure to 12 environments colors of red and yellow with adjusted saturation and brightness, were statistically analyzed using t-test and two-way ANOVA. The results show that the HRV values in the two groups did not significantly vary in response to the changes in hue, brightness and saturation. The two groups’ stress factors distinguished according to the stress levels by the PWI scale affected the In(LF) parameter, which demonstrates that the PWI index can be utilized as a reliable scale for measuring stress levels. The ultra-short HRV measurement record and the use of a sole In(LF) parameter for stress assessment are regarded as the limitations of this study.
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Zohdi H, Egli R, Guthruf D, Scholkmann F, Wolf U. Color-dependent changes in humans during a verbal fluency task under colored light exposure assessed by SPA-fNIRS. Sci Rep 2021; 11:9654. [PMID: 33958616 PMCID: PMC8102618 DOI: 10.1038/s41598-021-88059-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 04/01/2021] [Indexed: 02/03/2023] Open
Abstract
Light evokes robust visual and nonvisual physiological and psychological effects in humans, such as emotional and behavioral responses, as well as changes in cognitive brain activity and performance. The aim of this study was to investigate how colored light exposure (CLE) and a verbal fluency task (VFT) interact and affect cerebral hemodynamics, oxygenation, and systemic physiology as determined by systemic physiology augmented functional near-infrared spectroscopy (SPA-fNIRS). 32 healthy adults (17 female, 15 male, age: 25.5 ± 4.3 years) were exposed to blue and red light for 9 min while performing a VFT. Before and after the CLE, subjects were in darkness. We found that this long-term CLE-VFT paradigm elicited distinct changes in the prefrontal cortex and in most systemic physiological parameters. The subjects' performance depended significantly on the type of VFT and the sex of the subject. Compared to red light, blue evoked stronger responses in cerebral hemodynamics and oxygenation in the visual cortex. Color-dependent changes were evident in the recovery phase of several systemic physiological parameters. This study showed that the CLE has effects that endure at least 15 min after cessation of the CLE. This underlines the importance of considering the persistent influence of colored light on brain function, cognition, and systemic physiology in everyday life.
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Affiliation(s)
- Hamoon Zohdi
- University of Bern, Institute of Complementary and Integrative Medicine, Fabrikstrasse 8, 3012, Bern, Switzerland
| | - Rahel Egli
- University of Bern, Institute of Complementary and Integrative Medicine, Fabrikstrasse 8, 3012, Bern, Switzerland
| | - Daniel Guthruf
- University of Bern, Institute of Complementary and Integrative Medicine, Fabrikstrasse 8, 3012, Bern, Switzerland
| | - Felix Scholkmann
- University of Bern, Institute of Complementary and Integrative Medicine, Fabrikstrasse 8, 3012, Bern, Switzerland
- Biomedical Optics Research Laboratory, Neonatology Research, Department of Neonatology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland
| | - Ursula Wolf
- University of Bern, Institute of Complementary and Integrative Medicine, Fabrikstrasse 8, 3012, Bern, Switzerland.
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Rees O, Whitney L. The Sleep Paralysis Nightmare, Wrathful Deities, and the Archetypes of the Collective Unconscious. PSYCHOLOGICAL PERSPECTIVES-A QUARTERLY JOURNAL OF JUNGIAN THOUGHT 2020. [DOI: 10.1080/00332925.2020.1738189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Dib S, Wells JCK, Fewtrell M. A within-subject comparison of different relaxation therapies in eliciting physiological and psychological changes in young women. PeerJ 2020; 8:e9217. [PMID: 32509467 PMCID: PMC7247525 DOI: 10.7717/peerj.9217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 04/28/2020] [Indexed: 12/04/2022] Open
Abstract
Background Stress reactivity can be different in women compared to men, which might consequently influence disease risk.Stress in women may also generate adverse physiological effects on their offspring during pregnancy or lactation. The objective of this study was to compare the effects of different relaxation interventions on physiological outcomes and perceived relaxation in healthy young women, to assist in identifying the most appropriate intervention(s) for use in a subsequent trial for mothers who deliver prematurely. Methods A within-subject study was conducted in 17 women of reproductive age comparing five different relaxation interventions (guided-imagery meditation audio (GIM), music listening (ML), relaxation lighting (RL), GIM+RL, ML+RL), with control (silence/sitting), assigned in random order over a 3–6 week period. Subjective feelings of relaxation (10-point scale), heart rate (HR), systolic and diastolic blood pressure (SBP, DBP), and fingertip temperature (FT) were measured before and after each technique Results All interventions significantly increased perceived relaxation and FT, while music also significantly reduced SBP (p < 0.05). Compared to control, HR significantly decreased following GIM (mean difference = 3.2 bpm, p < 0.05), and FT increased (mean difference = 2.2 °C, p < 0.05) and SBP decreased (mean difference = 3.3 mmHg, p < 0.01) following ML. GIM + RL followed by GIM were the most preferred interventions. Conclusions Based on preference, simplicity, and the physiological and psychological effects, GIM and ML were identified as the most effective tools for reducing stress and improving relaxation. These techniques warrant further research in larger samples and other populations.
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Affiliation(s)
- Sarah Dib
- UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Jonathan C K Wells
- UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Mary Fewtrell
- UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
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Korompeli A, Kavrochorianou N, Molcan L, Muurlink O, Boutzouka E, Myrianthefs P, Fildissis G. Light affects heart rate's 24‐h rhythmicity in intensive care unit patients: an observational study. Nurs Crit Care 2019; 24:320-325. [DOI: 10.1111/nicc.12433] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 12/26/2022]
Affiliation(s)
- Anna Korompeli
- National and Kapodistrian University of AthensUniversity ICU, Ag. Anargyroi General Hospital Athens Greece
| | - Nadia Kavrochorianou
- National and Kapodistrian University of AthensUniversity ICU, Ag. Anargyroi General Hospital Athens Greece
| | - Lubos Molcan
- Department of Animal Physiology and Ethology, Faculty of Natural SciencesComenius University Bratislava Slovakia
| | - Olav Muurlink
- Central Queensland University, BrisbaneGriffith Institute of Educational Research Brisbane Queensland Australia
| | - Eleni Boutzouka
- National and Kapodistrian University of AthensUniversity ICU, Ag. Anargyroi General Hospital Athens Greece
| | - Pavlos Myrianthefs
- National and Kapodistrian University of AthensUniversity ICU, Ag. Anargyroi General Hospital Athens Greece
| | - Georgios Fildissis
- National and Kapodistrian University of AthensUniversity ICU, Ag. Anargyroi General Hospital Athens Greece
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Modi P, Jha K, Kumar Y, Kumar T, Singh R, Mishra A. The effect of short-term exposure to red and blue light on the autonomic tone of the individuals with newly diagnosed essential hypertension. J Family Med Prim Care 2019; 8:14-21. [PMID: 30911475 PMCID: PMC6396577 DOI: 10.4103/jfmpc.jfmpc_375_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The research study aimed to study the effect of short term exposure to light basically red, blue and white on the autonomic tone of essential hypertensive individuals. The objective was to find out the baseline cardiac autonomic function along with the effect of these lights on the cardiac autonomic function among them. Till date few if any study have been conducted upon the individuals with certain disorder as common as essential hypertension. This was a cross sectional observational study conducted in the institute itself that included 77 newly diagnosed hypertensive subjects who willingly participated in the study. After written informed consent, brief history taking with the help of self-made questionnaire and clinical examination, they were randomized to different intervention groups (IG) namely IG I (red) IG II (blue) and IG III (white). HRV analysis of the last 5-6 minutes of both the baseline and color exposure was finally analyzed using MS Excel version 13 and Graph Pad Prism version 7.05. Different HRV parameters have been found to be affected differently on different color exposures. Red has shown to have an impact, mainly on the sympathetic system whereas white showed a dominant vagal component thus acting as a parasympathetic regulator. On one hand, where no conclusive result was found on blue light exposure, white light showed the most prominent results affecting various time and frequency components of HRV like SDRR, TP, LF etc. The present study, both, contradicts as well as supports various other works done on the similar area of interest. One reason of such high variation in different results is because HRV is itself a very dynamic function affected by even a slight change in both the internal and external environment of the subject. As artificial lights of various colors are part and parcel of the aesthetics and designing of most of the work environment all over world, it is very pertinent to study its impact upon human health status. The outcome of the study may play a decisive role in the diagnostics and therapeutics of essential hypertension in days to come. Furthermore, on the basis of the present findings, a future study could be undertaken with bigger data base addressing the limitations of the present study to find some conclusive evidence in the area highlighted.
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Affiliation(s)
- Pratibha Modi
- Department of Physiology, All India Institute of Medical Sciences, Patna, Bihar, India
| | - Kamlesh Jha
- Department of Physiology, All India Institute of Medical Sciences, Patna, Bihar, India
| | - Yogesh Kumar
- Department of Physiology, All India Institute of Medical Sciences, Patna, Bihar, India
| | - Tribhuwan Kumar
- Department of Physiology, All India Institute of Medical Sciences, Patna, Bihar, India
| | - Ramji Singh
- Department of Physiology, All India Institute of Medical Sciences, Patna, Bihar, India
| | - Abhilasha Mishra
- Department of Physiology, All India Institute of Medical Sciences, Patna, Bihar, India
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Scholkmann F, Hafner T, Metz AJ, Wolf M, Wolf U. Effect of short-term colored-light exposure on cerebral hemodynamics and oxygenation, and systemic physiological activity. NEUROPHOTONICS 2017; 4:045005. [PMID: 29181427 PMCID: PMC5695650 DOI: 10.1117/1.nph.4.4.045005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/02/2017] [Indexed: 05/20/2023]
Abstract
There is not yet a comprehensive view of how the color of light affects the cerebral and systemic physiology in humans. The aim was to address this deficit through basic research. Since cerebral and systemic physiological parameters are likely to interact, it was necessary to establish an approach, which we have termed "systemic-physiology-augmented functional near-infrared spectroscopy (SPA-fNIRS) neuroimaging." This multimodal approach measures the systemic and cerebral physiological response to exposure to light of different colors. In 14 healthy subjects (9 men, 5 women, age: [Formula: see text] years, range: 24 to 57 years) exposed to red, green, and blue light (10-min intermittent wide-field visual color stimulation; [Formula: see text] blocks of visual stimulation), brain hemodynamics and oxygenation were measured by fNIRS on the prefrontal cortex (PFC) and visual cortex (VC) simultaneously, in addition with systemic parameters. This study demonstrated that (i) all colors elicited responses in the VC, whereas only blue evoked a response in the PFC; (ii) there was a color-dependent effect on cardiorespiratory activity; (iii) there was significant change in neurosystemic functional connectivity; (iv) cerebral hemodynamic responses in the PFC and changes in the cardiovascular system were gender and age dependent; and (v) electrodermal activity and psychological state showed no stimulus-evoked changes, and there was no dependence on color of light, age, and gender. We showed that short-term light exposure caused color-dependent responses in cerebral hemodynamics/oxygenation as well as cardiorespiratory dynamics. Additionally, we showed that neurosystemic functional connectivity changes even during apparently stress-free tasks-an important consideration when using any of the hemodynamic neuroimaging methods (e.g. functional magnetic resonance imaging, positron emission tomography, and fNIRS). Our findings are important for future basic research and clinical applications as well as being relevant for everyday life.
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Affiliation(s)
- Felix Scholkmann
- University of Bern, Institute of Complementary Medicine, Bern, Switzerland
- University of Zurich, University Hospital Zurich, Biomedical Optics Research Laboratory, Department of Neonatology, Zurich, Switzerland
| | - Timo Hafner
- University of Bern, Institute of Complementary Medicine, Bern, Switzerland
| | | | - Martin Wolf
- University of Zurich, University Hospital Zurich, Biomedical Optics Research Laboratory, Department of Neonatology, Zurich, Switzerland
| | - Ursula Wolf
- University of Bern, Institute of Complementary Medicine, Bern, Switzerland
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Metz AJ, Klein SD, Scholkmann F, Wolf U. Continuous coloured light altered human brain haemodynamics and oxygenation assessed by systemic physiology augmented functional near-infrared spectroscopy. Sci Rep 2017; 7:10027. [PMID: 28855556 PMCID: PMC5577215 DOI: 10.1038/s41598-017-09970-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 08/02/2017] [Indexed: 11/12/2022] Open
Abstract
Exposure to artificial coloured light is unavoidable in our modern life, but we are only just beginning to understand the impact of coloured light on human physiology. The aim of the present study was to determine effects of coloured light exposure on human systemic and brain physiology using systemic physiology augmented functional near-infrared spectroscopy (SPA-fNIRS). We measured changes in haemoglobin concentrations and tissue oxygen saturation in the left and right prefrontal cortices (L-PFC, R-PFC) by fNIRS, and also recorded skin conductance (SC), partial pressure of end-tidal CO2 (PETCO2), and heart-rate variability variables. 17 healthy adults (median age: 29 years, range: 25-65 years, 6 women) were exposed to blue, red, green, or yellow light for 10 minutes. Pre-light and post-light conditions were in darkness. In the L-PFC the yellow evoked a brain activation. SC and PETCO2 did not change during any of the coloured light exposures, but SC increased and PETCO2 decreased for all colours (except green) in the post-light period. Changes in L-PFC haemoglobin concentration were also observed during the post-light period but have to be interpreted with care, because heart rate and SC increased while PETCO2 decreased. The detected effects are potentially of high relevance for choosing room lighting and may possibly be applied therapeutically.
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Affiliation(s)
- A J Metz
- University of Bern, Institute of Complementary Medicine, Bern, Switzerland
| | - S D Klein
- University of Bern, Institute of Complementary Medicine, Bern, Switzerland
| | - F Scholkmann
- University of Bern, Institute of Complementary Medicine, Bern, Switzerland
- University Hospital Zurich, University of Zurich, Department of Neonatology, Biomedical Optics Research Laboratory, Zurich, Switzerland
| | - U Wolf
- University of Bern, Institute of Complementary Medicine, Bern, Switzerland.
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Yuda E, Ogasawara H, Yoshida Y, Hayano J. Suppression of vagal cardiac modulation by blue light in healthy subjects. J Physiol Anthropol 2016; 35:24. [PMID: 27716445 PMCID: PMC5051049 DOI: 10.1186/s40101-016-0110-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/09/2016] [Indexed: 11/21/2022] Open
Abstract
Background In the contemporary life environments, our body is increasingly exposed to various sources of colored light, which may affect our physiological functions as non-image-forming effects. We examined the impacts of colored lights on the autonomic functions by the analysis of heart rate variability (HRV). Methods A lighting device consisting of four organic light-emitting diode (OLED) modules (55 × 55 mm2) with adjustable red-green-blue color was secured 24 cm above the eyes of subject lying supine in a light-shielded laboratory. Following a 15-min supine rest, electrocardiogram and respiration were measured continuously during 3-min darkness, 6-min colored OLED illumination, and 3-min darkness under paced breathing (15 breath/min). The measurements were repeated at a 45-min interval for red, green, and blue lights with melanopsin-stimulating photon flux density (MSPFD) of 0.00, 0.10, and 0.20 μmol/m2/s, respectively, in 12 healthy subjects (23 ± 2 years, two females). Additionally, the effects of blue lights with 0.20, 0.10, and 0.04 μmol/m2/s MSPFD were examined in four healthy subjects (25–39 years, two females). HRV was analyzed for low-frequency (LF, 0.04–0.15 Hz) and high-frequency (HF, 0.20–0.30 Hz) power and LF-to-HF ratio (LF/HF). Results Compared to darkness before lighting, HF power decreased (P < 0.001) and LF/HF increased (P = 0.024) during lighting on average of all color lights, whereas HF power showed a greater decrease with blue light than with red and green lights (P < 0.05 for both). The decrease in HF power lasted even during darkness after lighting (P < 0.001). HF power decreased with blue light with 0.20 μmol/m2/s MSPFD (P < 0.001) but not with that with 0.10 or 0.04 μmol/m2/s (P = 0.1 and 0.9, respectively). Conclusions Vagal cardiac modulation is suppressed by OLED blue light in healthy subjects most likely through melanopsin-dependent non-image-forming effect.
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Affiliation(s)
- Emi Yuda
- Department of Medical Education, Nagoya City University Graduate School of Medical Sciences, Kawasumi 1 Mizuho-cho Mizuho-ku, Nagoya, 467-8601, Japan
| | - Hiroki Ogasawara
- Department of Medical Education, Nagoya City University Graduate School of Medical Sciences, Kawasumi 1 Mizuho-cho Mizuho-ku, Nagoya, 467-8601, Japan
| | - Yutaka Yoshida
- Department of Medical Education, Nagoya City University Graduate School of Medical Sciences, Kawasumi 1 Mizuho-cho Mizuho-ku, Nagoya, 467-8601, Japan
| | - Junichiro Hayano
- Department of Medical Education, Nagoya City University Graduate School of Medical Sciences, Kawasumi 1 Mizuho-cho Mizuho-ku, Nagoya, 467-8601, Japan.
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