Rodney Heller LC, CLEP Senior Lighting Designer & Lighting Evangelist Energy Performance Lighting Cottage Grove, WI
Not promoting any product or manufacturer Based on existing body of research & my experience Help from Steven Lockley Ph.D., Harvard Medical School, Brigham & Women s Hospital, Boston I will get a little geeky on this; it is all about the science!
You will Learn: How light affects Health How light affects Productivity How light affects Safety Light is more than just saving energy
We were built to get up with the sun and go to bed with the sun Unfortunately societal pressures do not allow us to live as we evolved This effects us on a daily basis Alertness goes down SAD Seasonal Affective Disorder Eyes get tired Tired at the end of work day Poor sleep habits
Circadian Rhythm Circadian Rhythm refers to the approximately 24 hour cycle observed in many plants and animals. It is related to the body s production of 2 unique hormones, Cortisol and Melatonin. It is reset through light. Figure from thepaleomom.com, Dr. Sarah Ballantyne, PHD author of Regulating Circadian Rhythm (and why that s important) Feb. 27, 2014.
2 visual photoreceptors - Rods & Cones Photopic day vision Scotopic night vision 1 non-visual photoreceptor - iprgc intrinsically photosensitive Retinal Ganglion Cells Most primitive form of vision in mammals Does not see, just turns things on and turns things off in our body Discovered in 1999
Spectral Power Distribution of natural sunlight We are all products of light Natural daylight & darkness
Increases Alertness 480 nm 4100k Fluorescent Daylight
Increased risk of accident & injury (Folkard & Tucker, 2003) Compromised alertness, performance and health costs ~$200 billion annually (Kerin & Aguirre, 2005) In General, higher risk of cancer, cardiac disease, Type II diabetes, and obesity Review your records, they bear out the increased incidence
Alertness Peak 5000k LED There is even better lighting on the market today
4100k Fluorescent 5000k LED
Non-pharmacological sleepiness countermeasure Safe, reversible, short-acting, inexpensive High levels of caffeine use illustrate need Offices, schools, colleges, factories, control rooms Military, security, transport, (pilots, truckers) Healthcare (hospitals, nursing homes, rehabilitation) Wherever enhanced alertness, cognitive function or safety is important S. Lockley; Harvard Medical School Brigham & Women s Hospital
Direct immediate effects of light in blue spectrum Improves alertness Improves objective EEG correlates of alertness Improve neurobehavioral performance Induces melatonin suppression Induces cortisol stimulation (at some times of day) Increases heart rate and temperature Drives pupillary constriction response S. Lockley; Harvard Medical School Brigham & Women s Hospital
Peter R Mills, Susannah C Tomkins, and Luc JM Schlangen Background The effects of lighting on the human circadian system are wellestablished. The recent discovery of 'non-visual' retinal receptors has confirmed an anatomical basis for the non-image forming, biological effects of light and has stimulated interest in the use of light to enhance wellbeing in the corporate setting. Results Individuals in the intervention arm of the study showed a significant improvement in self-reported ability to concentrate at study end as compared to those within the control arm (p < 0.05). The mean individual score on a 5 point Likert scale improved by 36.8% in the intervention group, compared with only 1.7% in the control group. The majority of this improvement occurred within the first 7 weeks of the 14 week study. Substantial within group improvements were observed in the intervention group in the areas of fatigue (26.9%), alertness (28.2%), daytime sleepiness (31%) and work performance (19.4%), as assessed by the modified Columbia Scale, and in the areas of vitality (28.4%) and mental health (13.9%), as assessed by the SF-36 over the study period.
Blue-enriched white light in the workplace improves self-reported alertness, performance and sleep quality N=94 workers on 2 floors with ( ) and without ( ) 17000K lamps for 4 weeks each self-reported alertness, performance and sleep quality Viola et al Scand J Work Environ Health 2008
Shadab A. Rahman, PhD; Erin E. Flynn-Evans, PhD; Daniel Aeschbach, PhD; George C. Brainard, PhD; Charles A. Czeisler, MD, Ph; Steven W. Lockley, PhD Study Objectives: Previous studies have demonstrated short-wavelength sensitivity for the acute alerting response to nocturnal light exposure. We assessed daytime spectral sensitivity in alertness, performance, and waking electroencephalogram (EEG). Measurements and Results: Daytime and nighttime 460-nm light exposure significantly improved auditory reaction time (P < 0.01 and P < 0.05, respectively) and reduced attentional lapses (P < 0.05), and improved EEG correlates of alertness compared to 555-nm exposure. Whereas subjective sleepiness ratings did not differ between the two spectral conditions during the daytime (P > 0.05), 460-nm light exposure at night significantly reduced subjective sleepiness compared to 555-nm light exposure at night (P < 0.05). Moreover, nighttime 460-nm exposure improved alertness to near-daytime levels. Conclusions: The alerting effects of short-wavelength 460-nm light are mediated by counteracting both the circadian drive for sleepiness and homeostatic sleep pressure at night, but only via reducing the effects of homeostatic sleep pressure during the day.
Short-wavelength sensitivity for the acute alerting effects of light 460 nm light is more effective at enhancing alertness and performance than 555 nm light during both night and day Subjective sleepiness rating (KSS) Mean auditory reaction time (ms) Number of lapses >500 msec 9 8 7 6 5 4 3 2 500 400 300 200 20 16 12 8 4 0 DAYTIME LIGHT EXPOSURE P>0.05 P<0.0001 P<0.001 9 8 7 6 5 4 3 2 500 400 300 200 20 16 12 8 4 0 NIGHT TIME LIGHT EXPOSURE P<0.0001 P<0.0001 P<0.0001 9 8 7 6 5 4 3 350 325 300 275 250 225 8 6 4 2 0 P<0.0001 P<0.0001 P<0.0001 * * * ** * 2 4 6 8 10 12 14 12 14 16 18 20 22 24 DAY NIGHT Time from habitual wake (h) Time from habitual wake (h) Lockley et al., Sleep 2006; Rahman et al. Sleep 2014
Blue light is an effective countermeasure for night time performance decrements associate with circadian desynchrony and can restore performance to near daytime levels in the laboratory Blue light is an effective counter measure for day-time performance decrements in the laboratory Office and shiftwork studies during the day and night show improvements in alertness and performance with higher CCT light Multiple healthcare application show benefits of acute light therapy (SAD, fatigue) and stronger light-dark cycles (dementia, sleep-wake) with higher intensity or CCT light S. Lockley; Harvard Medical School Brigham & Women s Hospital
Minimum of 5000k, prefer 6500k Adjust lighting to task performed Most people work on computers today Lighting was designed for paper based task Too bright causes glare Need to lower illuminance to remove glare Use task lighting Lower light levels need more light at 460-480nm Measure light on vertical plane
Any low kelvin lighting Anything below 5000k 2700k, 3500k, 4100k puts people to sleep Lighting designers like it brings out earth tones Lighting that flickers LED direct wire T LEDs Epilepsy, autistic, migraine sufferers Eye strain for all of us Dangerous with moving parts or machinery
Focus on the occupant; energy savings will fall into place Do it right: Lower accident rates Lower error rates Increase productivity Healthier workforce 60-75% energy savings Non energy savings greater value than energy savings!
Rich blue light during the day (or work shift) Warm, yellowish, light after 6 PM No blue light in your bedroom, red or orange is ok; No blue LED indicator or night lights Complete darkness is best Computer work after 6:00PM, use f.lux https://justgetflux.com/ Just think how we evolved; Day-Night
Questions? Rodney Heller LC, CLEP Cottage Grove WI 53527 608-661-5555 rheller@energyperformance.net