Lighting for Human Health, Productivity, & Safety

Transcription

1 Lighting for Human Health, Productivity, & Safety Rodney Heller LC, CLEP Senior Lighting Designer & Managing Partner Energy Performance Lighting Cottage Grove, WI

2 About this Presentation Not promoting any product or manufacturer Based on my experience and research Steve Lockley Ph.D., Harvard Medical School, Brigham & Women s Hospital, led or participated and vetted the research I based this presentation on

3 Goals of this Seminar You will learn that light is more than just potentially saving energy You will learn about the importance of the nonvisual effects light Begin to understand visible light s crucial role in human physiology

4 Visual & Non-Visual Receptors 2 visual photoreceptors - Rods & Cones Photopic day vision Scotopic night vision 1 non-visual photoreceptor - Ganglion cells iprgc Discovered in 1999 Most primitive form of vision in mammals Tells us day & night & time of year

5 Anatomy of the Eye

6 Light Applications - General 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, captains, truck/car/train engineers) Safety-sensitive occupations (physicians, nurses, nuclear ) Healthcare (hospitals, care homes, rehabilitation, home, therapy) Anywhere where enhanced alertness, cognitive function or safety is important

7 Applying Light Challenge is to incorporate these benefits into design Lighting design to optimize visual and non-visual effects Flexible, smart lighting systems with user interaction

8 Nonvisual Photoreception Neuroendocrine & neurobehavioral responses Direct immediate effects of light Improves subjective 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 Stimulates circadian clock gene expression

9 Circadian Effect of Light Circadian entrainment (clock synchronization) Circadian phase shifting (clock resetting) Photoperiodism and seasonality Solar navigation

10 VISIBLE LIGHT SPECTRUM

11 Non-Visual Photoreception Action spectra for melatonin suppression peak at ~460 nm and do not match known rod and cone photoreceptors scotopic photopic l max = nm 90 mins exposure Brainard et al. J Neurosci 2001 l max = 459 nm 30 mins exposure Thapan et al. J Physiol 2001

12 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 DAYTIME LIGHT EXPOSURE P>0.05 P< P< Time from habitual wake (h) NIGHT TIME LIGHT EXPOSURE P< P< P< Time from habitual wake (h) P< P< P< DAY * * * ** * NIGHT Lockley et al., Sleep 2006; Rahman et al. Sleep 2014

13 Melatonin suppression response 555 nm vs 480 nm 555 nm 460 nm Gooley et al. Sci Transl Med, 2010

14 How Do We Apply Light? Healthy light and healthy darkness are necessary for optimum human health, productivity & safety We need short wave length light during the day and long wave length or no light at night Societal demands means our work day is our day regardless of the shift, 1 st, 2 nd, or 3 rd 100 years ago and the previous million, we spent over 90% of our day outside; we got up with the sun went to bed with the sun and never had a 3 rd shift

15 Applying Light

16 1 st & 2 nd Shift Lots of short wave length light, nm Can not rebuild all work spaces To get short wavelength light should be a minimum of 5000k, I prefer 6500k and higher It all depends on how much of the light source is in that nm range

17 The Effect of High Correlated Colour Temperature Office Lighting on Employee Wellbeing and Work Performance Peter R Mills, 1,2 Susannah C Tomkins, 1 and Luc JM Schlangen 3 Abstract Background The effects of lighting on the human circadian system are well-established. 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. Methods A prospective controlled intervention study was conducted within a shift-working call centre to investigate the effect of newly developed fluorescent light sources with a high correlated colour temperature (17000 K) upon the wellbeing, functioning and work performance of employees. Five items of the SF-36 questionnaire and a modification of the Columbia Jet Lag scale, were used to evaluate employees on two different floors of the call centre between February and May Questionnaire completion occurred at baseline and after a three month intervention period, during which time one floor was exposed to new high correlated colour temperature lighting and the other remained exposed to usual office lighting. Two sided t-tests with Bonferroni correction for type I errors were used to compare the characteristics of the two groups at baseline and to evaluate changes in the intervention and control groups over the period of the study. 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. Conclusion High correlated colour temperature fluorescent lights could provide a useful intervention to improve wellbeing and productivity in the corporate setting, although further work is necessary in quantifying the magnitude of likely benefits.

18 Color Temp of the Sky

19 General Recommendations for Applying Light Should know light color based on the wave length in NM, not kelvin Should have minimum of 5000k, prefer 6500k Adjust lighting to task performed Most people work on computers today Most 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 nm

20 Work Lighting to Avoid This is for the normal work environment, not in restaurants or places where you want to wind down or relax Any low kelvin lighting Anything below 5000k 2700k & 3500k puts people to sleep Makes skin look more natural Parabolic louvers or paracubes

21 3 rd Shift Humans not built for 3 rd shift (rats were!) Melatonin production starts as day ends or as the sun goes down People are tired Homeostatic sleep pressure Circadian sleep pressure

22 3 rd shift Studies have documented 60% increase in breast cancer 50% increase in prostate cancer 20% increase in general health problems; cardiac disease, type II diabetes, & obesity Obesity Stomach shuts down at night Body temp, pulse rate, breathing rate are all lower

23 Most Organs have a Circadian Clock SCN Most fatigue related accidents occur at 5 a.m. Heart Peak rate of heart attacks occurs at 9 a.m. Heart attacks jump by 5% on the Monday after the clocks spring forward for Daylight Savings Time Lung Liver

24 The Role of Environmental Lighting and Circadian Disruption in Cancer and Other Diseases

25 3 rd shift Problems Error rate increases Accident rate increases Health insurance costs/employee increases This is bad for the employee, the supervisor, & company

26 Need to Get Lighting Right Install high kelvin for the workers Not for patients or people who are supposed to be sleeping Need to get that blue to the pupil, nm Turn 3 rd shift into the work day Must sleep in a totally dark environment Minimize noise too, sleep in basement preferably Flip night into day Get the deep circadian peak & valley every day

27 Diurinal Spectral Sensitivity of the Acute Alerting Effects of Light

28 NASA Mission Control 3 rd shift Installed 8000k lamps in the break room Combined with moderate amount of exercise Documented 26% reduction in errors

29 Non-Visual Photoreception Light is the most powerful time cue for resetting the circadian pacemaker and ensuring correct synchronization of the internal clock with the environment Failure to entrain the circadian pacemaker results in sleep disorders, fatigue, performance problems, hormone and metabolic disorders Common examples of circadian desynchronization are caused by shift-work, jet lag, advanced and/or delayed sleep phase disorder

30 Summary - Neurobiology 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 Pilot school studies show benefits of higher CCR fluorescent and LED lighting on the concentration and performance although mechanism (circadian and/or acute effects) unknown Ground studies underway testing the effects of prototype LED polychromatic lighting system on pre-sleep sleepiness, post-wake alertness and circadian phase resetting for the space station 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

31 Energy Savings Focus on the occupant You get lighting right for the occupant, the energy savings falls into place Easy to get 40% energy savings Do it right and you can get 70-80% energy savings and increase productivity by %? Depends on task

32 Focus on the Occupant! Get that right and the energy savings falls into place Questions?