Light and Health: It is more than tunable white light! by Mariana Figueiro

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Designers Light Forum
Light and Health:
It is more than tunable white light!
Mariana G. Figueiro, PhD
Lighting Research Center
Rensselaer Polytechnic Institute
March 28, 2017
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Light and Health:
It is more than tunable white
light!
Mariana G. Figueiro, PhD
March 28, 2017

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Credit(s) earned on completion of
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Electric lighting systems engineered to
deliver "healthy" lighting are flooding
the market, and so are claims
associated with such products and
their applications.
This talk will cover what we know,
what we don't know and we need to
know to deliver healthy lighting to
various populations, from premature
infants to Alzheimer’s disease
patients.
Course Description
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Learning
Objectives
1. Understand basics of circadian system
2.Undestand lighting characteristics affecting the circadian system
3.Understand how to calculate circadian stimulus
4. Understand what populations light has been shown to affect
sleep, mood and behavior
At the end of the this course, participants will be able to:
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Lighting affects three systems
Visual + non-visual + message
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Distribution
Appearance Visual System
Visual
Performance
Performance,
Well-being,
Satisfaction, and
Comfort
Alerting Effects Non-Visual Systems Phase Shift
Amount Spectrum DurationDistribution Timing
Culture,
Experience,
Expectations
TimingSpectrum DurationAmount
Lighting affects three systems
Visual
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Appearance Visual System
Visual
Performance
Performance,
Well-being,
Satisfaction, and
Comfort
Alerting Effects Non-Visual Systems Phase Shift
Amount Spectrum DurationDistribution Timing
Culture,
Experience,
Expectations
TimingSpectrum DurationAmount Distribution

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Relative visual performance
Size + Contrast + Illuminance + Age
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Luminance
contrast
Retinal
illuminance
Visual size
RVP
IESNA Handbook
Appearance/Brightness Perception
Warm 2700 K Cool 6500 K
Low100IxHigh350Ix
r = 0.7
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Control over glare, reflections and shadows
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Glare
Shadows
Reflection
Photo Researchers
Encarta
Doug Martin / Photo Researchers, Inc
Lighting affects three systems
Message
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Appearance Visual System
Visual
Performance
Performance,
Well-being,
Satisfaction, and
Comfort
Alerting Effects Non-Visual Systems Phase Shift
Amount Spectrum DurationDistribution Timing
Culture,
Experience,
Expectations
TimingSpectrum DurationAmount Distribution

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What is the message?
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vs.
Perceptual system
• Preference for view
• Biophilia hypothesis
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Lighting affects three systems
Non-Visual
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Appearance Visual System
Visual
Performance
Performance,
Well-being,
Satisfaction, and
Comfort
Alerting Effects Non-Visual Systems Phase Shift
Amount Spectrum DurationDistribution Timing
Culture,
Experience,
Expectations
TimingSpectrum DurationAmount Distribution
Circadian system
• Plants and animals exhibit
patterns of behavioral and
physiological changes over an
approximately 24-hour cycle that
repeat over successive days—
these are circadian rhythms
• circa = about; dies = day
• Circadian rhythms are
influenced by exogenous
and endogenous rhythms
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Light is the primary synchronizer
of circadian rhythms to local
position on Earth
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Light is the primary synchronizer of
circadian rhythms to local position on Earth
The natural, 24-hour,
light-dark cycle
light
retina
suprachiasmatic
nucleus
hypothalamus
thalamus
lateral geniculate
nucleus
pineal gland
signals to body
optic nerve
24.2
Adapted from National Library of Medicine image, 2007
(public domain)
…also the major disruptor
Circadian disruption and health
• Circadian disruption has been associated with:
– Poor sleep, poor performance and high stress
Eismann, E. A., Lush, E., & Sephton, S. E. (2010). Circadian effects in cancer-relevant psychoneuroendocrine and immune pathways.
Psychoneuroendocrinology, 35(7), 963-976.
Gumenyuk, V., Howard, R., Roth, T., Korzyukov, O., Drake, C.L. (2014) Sleep loss, circadian mismatch, and abnormalities in reorienting of attention in
night workers with shift work disorder. Sleep. March 1; 37(3): 545–556.
– Increased anxiety and depression
Du-Quiton, J., Wood, P. A., Burch, J. B., Grutsch, J. F., Gupta, D., Tyer, K., . . . Reynolds, J. L. (2010). Actigraphic assessment of daily sleep–activity pattern
abnormalities reflects self-assessed depression and anxiety in outpatients with advanced non-small cell lung cancer. Psycho-Oncology, 19(2), 180-189.
– Increased smoking
Kageyama, T., Kobayashi, T., Nishikido, N., Oga, J., & Kawashima, M. (2005). Associations of sleep problems and recent life events with smoking
behaviors among female staff nurses in Japanese hospitals. Industrial Health, 43(1), 133-141.
– Cardiovascular disease
Young, M. E., & Bray, M. S. (2007). Potential role for peripheral circadian clock dyssynchrony in the pathogenesis of cardiovascular dysfunction. Sleep
Medicine, 8(6), 656-667.
Maemura, K., Takeda, N., & Nagai, R. (2007). Circadian rhythms in the CNS and peripheral clock disorders: role of the biological clock in cardiovascular
diseases. Journal of Pharmacological Sciences, 103(2), 134-138.
– Type 2 diabetes
Kreier, F., Kalsbeek, A., Sauerwein, H. P., Fliers, E., Romijn, J. A., & Buijs, R. M. (2007). “Diabetes of the elderly” and type 2 diabetes in younger patients:
Possible role of the biological clock. Experimental Gerontology, 42(1), 22-27.
– Higher incidence of breast cancer
Schernhammer, E. S., Laden, F., Speizer, F. E., Willett, W. C., Hunter, D. J., Kawachi, I., & Colditz, G. A. (2001). Rotating night shifts and risk of breast
cancer in women participating in the Nurses' Health Study. Journal of the National Cancer Institute, 93(20), 1563-1568.
Hansen, J. (2006). Risk of breast cancer after night-and shift work: current evidence and ongoing studies in Denmark. Cancer Causes & Control, 17(4),
531-537.
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Lighting affects three systems
Visual + non-visual + message
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Distribution
Appearance Visual System
Visual
Performance
Performance,
Well-being,
Satisfaction, and
Comfort
Alerting Effects Non-Visual Systems Phase Shift
Amount Spectrum DurationDistribution Timing
Culture,
Experience,
Expectations
TimingSpectrum DurationAmount
Lighting characteristics
Spectral and absolute sensitivities
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Absolute sensitivity
Rea, M. S., Figueiro, M. G., Bullough, J. D., & Bierman, A. (2005). A model of phototransduction
by the human circadian system. Brain Research Reviews, 50(2), 213-228.
Rea, M. S., Figueiro, M. G., Bierman, A., & Hamner, R. (2012). Modelling the spectral sensitivity
of the human circadian system. Lighting Research and Technology, 44(4), 386-396.
Spectral sensitivity
outdoors
night
indoors
home
indoors
office
outdoors daytime

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Lighting characteristics
Timing
• Light can change the timing of sleep
and either promote entrainment or
cause disruption
– Morning light (after minimum core
body temperature) will advance the
timing of sleep
– Evening light (before minimum core
body temperature) will delay the
timing of sleep
– But, every photon counts!
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Rajaratnam S, Arendt J. Health in a 24-h Society.
The Lancet. 2001; 358(9286):999-1005.
Figueiro, MG. Delayed sleep phase
disorder: clinical perspective with a
focus on light therapy. Nature and
Science of Sleep 2016; 8:91-106 .
Our working hypothesis
• Tailored lighting intervention designed to promote
circadian entrainment can improve sleep, mood, and
behavior in various populations
– Sufferers from Seasonal Depression
– Office workers
– Submariners
– Teenagers with delayed sleep onset
– Older adults with early sleep onset
– Alzheimer’s disease and related dementia patients
– Cancer patients experiencing fatigue and sleep disturbances
• Tailored intervention designed to promote alertness in
dayshift and nightshift workers
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• Circadian stimulus: Metric for
quantifying effectiveness of light
sources for activating the circadian
system
• CS is equivalent to percent melatonin
suppression after 1-h exposure to the
light source
– An indication of how effective the
light source is for the circadian system
– Caveat: does not take into account
duration of exposure, photic history
and is based on acute melatonin
suppression (not phase shifting of the
clock)
• Threshold = 0.1 CS; half max = 0.3 CS;
saturation = 0.7 CS
Specification of the light stimulus
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Calculating CS
• Important considerations:
– Vertical Illuminance (light at the plane of the cornea)
– Light level
– Spectrum
– Timing and duration of exposure
– Photic history
• Exposure to CS of 0.3 or greater at the eye, for at least
1 hour in the early part of the day, is effective for
stimulating the circadian system
• CS calculator was developed to aid designers and
specifiers in selecting light sources that has the
potential for affecting the circadian system
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http://www.lrc.rpi.edu/resources/CircadianStimulusCalculator_30
Apr2016.xlsx
Important Considerations:
Light at the cornea
• When designing for circadian health, light at the
plane of the cornea becomes the primary target
• The ratio of horizontal illuminance to vertical
illuminance becomes important when looking at the
optic of a fixture
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Important Considerations:
Light level and Spectrum
• Lower light levels will achieve relatively lower CS
values unless compensated for by an SPD with more
power at shorter wavelengths
• Maintaining a single correlated color temperature
(CCT) throughout the day and achieving changes in
CS values is possible by simply increasing or
decreasing light level
• It’s important to request the SPD from the
manufacturer for any fixtures being considered. SPDs
can vary for a single CCT
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Important Considerations:
Light level and Spectrum
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Important Considerations:
Timing and duration
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Example of a recommended schedule for a senior care facility.
w Carefully consider who will be occupying the space.
› Schools and nursing homes will have occupants that require
circadian stimulation at different times.
w While 0.3 is a good minimum CS for stimulating the
circadian system, timing of exposure matters!
Tailored lighting intervention designed to promote
circadian entrainment
• Promote entrainment in various populations by
– Delivering high circadian stimulus (CS>0.3) during the day,
especially in the morning, and low CS (CS<0.1) in the
evening, to promote entrainment in Alzheimer’s disease
patients, older adults with early sleep onset, adolescents,
premature infants, cancer patients undergoing treatment)
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Circadian entrainment in adolescents
• USGBC research grant
– Light impacts students’ performance
and well-being by promoting their
circadian entrainment to the solar day
– Performed 3 field studies
• Demonstrated that lack of morning
circadian light delays dim light melatonin
onset, which can delay sleep onset
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Sponsor: USGBC
Figueiro MG and Rea MS. Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school
students. NeuroEndocrinology Letters. 2010; 31: 4.
Figueiro MG, Brons J, Plitnick B, Donlan B, Leslie R, and Rea MS. 2011. Measuring circadian light and its impact on adolescents. Lighting Research
and Technology (LR&T) 43(2):201-215.
Figueiro MG and Rea MS. 2010. Evening daylight may cause adolescents to sleep less in spring than in winter. Chronobiology International
27(6):1242-58.
Circadian entrainment in adolescents Impact of
computer screens on melatonin levels
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0%
10%
20%
30%
40%
50%
1 hour 2 hour
Melatonin suppression
Predicted suppression from Daysimeter data: 10%
Actual suppression: 25%
Figueiro and Overington, 2015

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Circadian entrainment in premature infants
• Premature infants
– Increased weight gain and reduced days in ventilator
in premature infants who received cycled light
compared to those who received either constant
light or constant darkness
– Improved sleep and circadian rhythms after
discharge in premature infants who received cycled
light compared to those who received either
constant light or constant darkness
• LRC is working with neonatologist to develop a light
blanket that can be placed on top of incubator
– Deliver cycled light
– Good color rendering
– Examination light
– Camera for parents to monitor infants
from afar
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Circadian entrainment in
persons with dementia
• Study tested the effectiveness of a tailored light
treatment on sleep quality, agitation and depression in
14 patients with Alzheimer’s disease and related
dementias living in nursing homes
• High circadian stimulation (CS>0.3) during daytime
• 300-400 lux at the cornea from waking to 6 pm
• Bluish-white light, CCT > 9000 K
• Results showed increase in sleep efficiency, total sleep
time, reduction in agitation and depression
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Sponsor: National Institute on Aging (R01AG034157)
Figueiro et al. 2014

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Circadian entrainment in persons with dementia
• Exposed 6 subjects to light table
(CS > 0.4) for 4 weeks
• Results showed a significant
increase in sleep efficiency and
duration
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Sponsor: National Institute on Aging (R01AG034157)
Figueiro M, Plitnick B and Rea M. Research Note: A self-luminous light table for
persons with Alzheimer’s disease. Light Res Technol. 2015: 1477153515603881.
Circadian entrainment to reduce fatigue in cancer patients
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Patients: Breast and gynecological cancer
survivors with clinically significant fatigue
Protocol: 30-min exposure to morning
light at baseline (after completion of
chemo), 4 weeks after intervention and 3
weeks after completion of the light
intervention
Light intervention: 30 min in front of a
light box within 30 min of waking.
Comparison: dim red light
Results: Significant improvement in
fatigue symptoms in the light condition

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Circadian entrainment to reduce fatigue in bone marrow
transplant patients
• In collaboration with Dr. William
Redd (Oncological Sciences), we
are investigating the impact of a
CS of 0.3 during the morning
hours on:
– Circadian markers (melatonin)
– Fatigue
– Depression
– Sleep
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Sponsor: National Cancer Institute, PI: Dr. Redd
Other applications to look out for
• Using light to reduce
– Sleep disturbances in Veterans with PTSD
– Post partum depression symptoms
– Delirium in ICU patients
– Sleep and fatigue in Parkinson’s disease patients
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Tailored intervention designed to promote alertness in
dayshift and nightshift workers
Promote acute alertness (e.g. = cup of coffee)
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.
Sponsor: Office of Naval Research (N00014-11-1-0572)
NIOSH/CDC
Lighting for nightshift workers
• Studies showed that red light, which does not suppress
nocturnal melatonin can:
– Improve subjective and objective measures of alertness
– Improve certain types of performance, similar to white light
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Sponsor: Office of Naval Research
Figueiro MG, Sahin L, Wood B and Plitnick B. Light at night and measures of alertness and performance: Implications
for shift workers. Biological Research for Nursing. 2014; In Press.

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Lighting for dayshift workers
• Studies showed that red light during post-lunch dip:
– Improves subjective and objective measures of alertness
– Improves certain types of performance
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Sponsor: Office of Naval Research (N00014-11-1-0572)
Sahin L, Wood BM, Plinick BA, Figueiro MG. Daytime light exposure: Effects on biomarkers, measures of alertness,
and performance. Behavioral Brain Research, 2014, 274:176-185.
Tips for designing for circadian health
• Think about layers of light!
– Some designers or specifiers may
have strict energy restrictions that
prevent CS targets from being
met.
• Consider using saturated blue (e.g.,
peak wavelength = 470 nm) LEDs as a
way to boost CS in creative ways.
– Studies have shown that red light
can have an acute alerting effect
without suppressing melatonin.
• Consider using red light as a way to
boost alertness for occupants.
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Lighting Patterns for Healthy Buildings
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w The LRC has developed a website detailing lighting
design patterns for:
› 24-h lighting scheme for seniors’ facilities
http://lightingpatternsforhealthybuildings.org/
Summary
• Light promotes entrainment to the local time on Earth
– Short-wavelength (blue) light is maximally effective;
– White light at higher light levels than needed for vision is
needed;
– Red light is not effective
• Morning light is “good” but evening light should be avoided
– Need to keep track of total light exposures
• Light has an acute alerting effect on people
– Brain activities
– Biomarkers other than melatonin levels
– Any color of light is effective
– Mechanisms are not well defined; need to develop a spectral
sensitivity
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Thank you.
www.lrc.rpi.edu
http://lightingpatternsforhealthybuildings.org/
http://www.lrc.rpi.edu/resources/CircadianStimulusCalculator_30A
pr2016.xlsx
This concludes The American Institute of Architects Continuing
Education Systems Course
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Acknowledgments
v Organizers of the event
Ø Gary Mann
v Lighting Research Center’s faculty, staff and students
Ø Mark S. Rea, PhD
Ø Barbara Plitnick, RN
Ø Sharon Lesage
Ø Kassandra Gonzalez, MS
Ø Ryan Bromm
Ø Andrew Bierman, MS
Ø Geoff Jones
Ø Dennis Guyon
Ø David Pedler
Ø Rohan Nagar
Ø Charlie Roohan
Ø Ryan Kutler
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Light and Health Project Sponsors
v National Institute on Aging
v National Institute on Drug Abuse
v National Institute of Nursing Research
v National Cancer Institute
v National Center for Complementary and Alternative Medicine
v Eunice Shriver National Institute of Child Health and Development
v National Institute of Occupational and Safety Health (CDC/NIOSH)
v General Services Administration (US GSA)
v US Department of State
v Office of Naval Research
v US Navy
v US Green Building Council
v The Swedish Energy Agency
v Boeing
v Google
v Acuity Brands
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Light and Health Alliance Sponsors
Acuity Brands, Cree, Current Powered by GE, Ketra, Philips Lighting, OSRAM, USAI Lighting
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The Light and Health Alliance is a collaboration
amongMembers(manufacturers,governmentorganizations
and NGOs, codes and standards bodies) and practitioners,
including architects, specifiers, medical facility managers
and physicians, to enable the broad adoption of lighting
for human health by producing factual information based
on basic and applied research and by visualizing future
applications.
Goals
• Conduct evaluations, demonstrations, and research
projects to develop practical devices and applications.
• Institutes to educate key audiences on light and health
with a particular emphasis on developing quantitative
lighting specifications.
• Presentations at conferences to promote the topic of
light and health, and the Light and Health Alliance.
Mission
To bridge the science of light and health to practical
applications, and to provide objective information based
on basic and applied research.
Member Benefits
• Meetings to inform Members of our latest research
activities, and discussions that would advance
attention to light and health in the public sector.
• Forums to provide an intellectual and physical
meeting place — a neutral ground for Members and
practitioners to share important insights.
• Influence to shape the research agenda.
• Early presentations of research results.
• Generation of pilot data — an essential requirement
for funding from the National Institutes of Health.
• Confidential research sponsored under separate
contract and IP agreement.
Cost: $30k per year; $20k per year for LRC Partners. A 3-year
commitment provides an additional $5,000 discount per
year. The LRC will establish and publically announce the
alliance after three sponsors join.
21 Union Street, Troy, NY 12180
518-687-7100
www.lrc.rpi.edu
Contact: Mariana G. Figueiro, PhD
figuem@rpi.edu
www.lrc.rpi.edu/programs/lightHealth/index.asp
Light and Health Alliance
Mission
To bridge the science of light and health to
practical applications, and to provide objective
information based on basic and applied
research
Goals:
• Conduct evaluations, demonstrations, and
research projects to develop practical
devices and applications
• Institutes to educate key audiences on light
and health with a particular emphasis on
developing quantitative
lighting specifications
• Presentations at conferences to promote
the topic of light and health, and the Light
and Health Alliance
Project collaborators
• Mt. Sinai Icahn School of Medicine
• Brown University
• Yale University
• Case Western Reserve University
• University of North Carolina, Chapel Hill
• Harvard University School of Public Health
• Skidmore College
• Duke University
• National Institute on Drug Abuse Intramural Research
• Netherlands Institute for Neuroscience
• Cornell University
• Naval Submarine Medical Research Laboratory
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