Lighting, Health and WellbeingWalking the Tightrope

Jonathan Green MSLL AMILPeLight Solutions Ltd

Contents

• Health– Biological

– Neurological

– Psychological

• Situations– Time

– Task

• Causes– Quantity

– Type

– Flicker

• Conclusions– Research

– Trends

Factors

• Human Needs

• Aesthetics

• Economic Constraints

Lighting quality model (Veitch, 1998) Courtesy of the National Research Council, Canada

Factors

• Human Needs

• Aesthetics

• Economic Constraints

Lighting quality model (Veitch, 1998) Courtesy of the National Research Council, Canada

Health Issues

• Psychological and Physical Symptoms

• De-synchronisation of Circadian Rhythms

• Amplified Carbon Footprint

Quality

• Visual system requirements inadequate for circadian system.

Spectrum• The visual system is most sensitive to the middle wavelength portion of

the spectrum, while the photo-biological system is responsive to the shorter wavelengths.

Timing• The visual system is not dependent on the timing of light exposure

whereas the circadian rhythm could phase advance or delay.

Duration• Melatonin production starts 10 minutes after bright light exposure initiated.

Spatial• For the visual system, light distribution is crucial to visual performance.

The circadian system only respond to the quantity of light.

Circadian Rhythms

• A roughly-24-hour cycle in the biochemical, physiological or behavioural processes.

• Can be entrained by external cues such as daylight.

• Important in determining sleeping and feeding patterns.

• Plays a role in the measurement and interpretation of day length • Linked to core body temperature, brain wave activity, hormone

production and cell regeneration

• Vital in the production of Melatonin.

Circadian Rhythms

From "The Body Clock Guide to Better Health" by Michael Smolensky and Lynne Lamberg; Henry Holt and Company.

Ganglion Cell

Intrinsically Photosensitive

Ganglion Cell

Layers of the iris

• Discovered in 2002.

• Turns light energy directly into brain signals.

• Important in determining sleeping and feeding patterns.

• Contribute to regulation and suppression of Melatonin.

• Absorbs light mainly in the blue wavelength.

Melatonin

• Regulates human daily body rhythms.

• Is an anti-oxidant with a particular role in the protection of nuclear and mitochondrial DNA.

• Produced by the pineal gland.

• Produced at night.

• Suppressed during daylight hours.

• Can be inhibited by disruption to circadian cycle.

Cycle Disruption

• Dim lighting by comparison to daylight (biological darkness).

• Melatonin suppression is inhibited possibly resulting in fatigue and reduced alertness.

• Production decreases, errors are made.

• For night-shift work, Melatonin manufacture is inhibited due to sleeping in partial daylight.

BS EN 12464-1:2002. Light and lighting. Lighting of work places - Offices

Task TypeMaintained Illuminance

Upper Limit for Direct Glare

Minimum Colour Rendering Index (Ra)

Filing, copying, etc. 300 19 80

Writing, typing, reading, data processing 500 19 80

Technical drawing 750 16 80

CAD work stations 500 19 80

Conference and meeting rooms 500 19 80

Reception desk 300 22 80

Health Risks Associated with Reduced Melatonin

• A contributory factor to the larger overall incidence of some cancers in the developed world (breast and prostate).

• Proposed as a likely factor in the significantly higher cancer rates in night shift workers.

• Reduced antioxidant protection against conditions associated with oxidative stress, particularly neurodegenerative diseases such as Alzheimer’s and Parkinson’s.

• Melatonin has also been found to decrease cognitive deterioration in individuals with Alzheimer’s disease.

• Melatonin may offer important protection against stroke-related damage and deterioration.

• Increased risk of sleep disorder development.

Flicker

Light flicker refers to quick, repeated changes in light.

• Regularity of voltage fluctuations.

• Size of voltage change.

• Light source (incandescent, fluorescent, HID etc).

• Lamp gain factor.

• Ambient light.

Flicker

• Fluorescent lamps using magnetic mains ballast flicker at twice the supply frequency (100Hz).

• Can cause moving machinery to appear still.

• Electromagnetic ballasts are associated with headaches and eyestrain.

• Individuals with high flicker fusion threshold are particularly affected.

• Studies show that fluorescent flicker increases the heart rate and therefore promotes anxiety in those who suffer from agoraphobia.

Flicker – Office Environment

• Most fluorescent lighting is seen in the peripheral.

• Flicker can be sensed at a higher frequency.

• The incidence of eyestrain and headaches in offices using high frequency gear is less than half.

Even with the availability of high-frequency control gear, the majority of lighting within the office or academic environment is provided by fluorescent lamps using magnetic ballasts which usually pulsate in brightness twice with each AC supply cycle.

Flicker – Office Environment

• Layout of the luminaires can cause visual discomfort.

• Headaches and epileptic seizures can be caused by patterns of stripes or regular arrays.

• Trend away from repetitive arrays of compact fluorescents is likely to be good for health.

Even with the availability of high-frequency control gear, the majority of lighting within the office or academic environment is provided by fluorescent lamps using magnetic ballasts which usually pulsate in brightness twice with each AC supply cycle.

Tunnel Lighting

The design of tunnel lighting requires careful consideration. It is well documented that frequencies between 10 and 60 Hz or 10 and 60 flashes per second can trigger seizures in those susceptible. In others it can cause headaches and eyestrain.

Tunnel Lighting

• Different luminaire arrays.

• Material of tunnel walls (reflective or matt).

• Impact of driver peripheral vision.

The design of tunnel lighting requires careful consideration. It is well documented that frequencies between 10 and 60 Hz or 10 and 60 flashes per second can trigger seizures in those susceptible. In others it can cause headaches and eyestrain.

BS5489-2:2003 may need revising to encompass:

Tunnel Lighting

On the subject of flicker the BS 5489-2:2003 states:

“The sensation of flicker can cause visual discomfort to drivers and in some cases can induce epileptic seizures. It is induced by periodic changes in luminance within the field of vision. Driving under incorrectly spaced luminaires within the tunnel or through an entrance zone with daylight louvers can give rise to this effect.”

• BS5489-2 states frequency between 2.5 and 15Hz.

• Seizures most likely at 18Hz.

• 50% of patients being sensitive to the 9Hz – 50Hz range.

Tunnel Lighting

Speed(mph)

Distance per second (m)

Spacing to simulate 2.5Hz (m)

Spacing to simulate 18Hz (m)

Spacing to simulate 60Hz (m)

30 13.41 5.36 0.75 0.22

40 17.88 7.15 0.99 0.30

50 22.35 8.94 1.24 0.37

60 26.82 10.73 1.49 0.45

70 31.29 12.52 1.74 0.52

A1 (M) Hatfield Tunnel – Known for causing Epileptic Seizures

ConclusionsVarious trends in interior lighting practice and their consequences for health and efficiency (A J Wilkins)

Trend Consequences

Away from ….And towards For Health For Efficiency

38mm diameter halophosphate fluorescent lamps with 50Hz ballast

High-frequency ballasts Good Good

Dimmable ballast Good if flicker free Good

Narrow band tri-phosphor lamps

Possible bad if 50Hz ballast

Marginal

26mm lamps Marginal Good

High-pressure sources Possibly bad Good

Incandescent lighting Compact fluorescent Bad if 50Hz ballast Good

Tungsten Tungsten-halogen Bad if high UV otherwise good

Good

Array of down-lighting luminaires on ceiling forming dazzle pattern

Irregular array Good None

Multiple point sources Bad if glaring or high UV Bad if incandescent

Up-lighting Bad if 50Hz ballast otherwise good

Possibly bad

Constant lighting Daylight controls Unknown Good

Occupancy sensors Unknown Good

Increased use of daylight Good Good

A J Wilkins, Nanno-Smith I, Slater A I and Bedocs L “Fluorescent lighting, headaches and eyestrain”, in LRT Vol 21 (1) 11-18 (1989).

Conclusions• Lighting only for visual acuity or to achieve decorative effects is

no longer acceptable.

• Proper use and colour of indoor and outdoor lighting is important to health to minimise circadian cycle interference.

• We must recognise the body’s need to sleep in darkness. The invention of the electric light leads us to believe that any task can be undertaken at any time. This simply is not the case.

• Precautions should be taken with the design and application of both indoor and outdoor lighting.

• Revision of BS5489-2:2003 to encompass current research into epilepsy, headaches and eyestrain.

• More information into health implications should be included in BS5489-2:2003 to provide greater insight for designers.

References

• J A Veitch, W Julian & A I Slater (1998) A framework for understanding and promoting lighting quality. In proceedings of the first CIE Symposium on Lighting Quality (J A Veitch ed), pp 237-241, Vienna, CIE Central Bureau.

• Zaidi FH, Hull JT, Peirson SN, Wulff K, Aeschbach D, Gooley JJ, Brainard GC, Gregory-Evans K, Rizzo JF 3rd, Czeisler CA, Foster RG, Moseley MJ, Lockley SW. Short-wavelength light sensitivity of circadian, pupillary, and visual awareness in humans lacking an outer retina. Curr Biol. 2007 Dec 18;17(24):2122-8

• Halberg Chronobiology Centre• Newman LA, Walker MT, Brown RL, Cronin TW, Robinson PR: "Melanopsin forms

a functional short-wavelength photopigment", Biochemistry. 2003 Nov 11;42(44):12734-8.

• Küller R, Laike T (1998). "The impact of flicker from fluorescent lighting on well-being, performance and physiological arousal". Ergonomics 41 (4): 433–47.

References

• Veitch JA, McColl SL (1995). "Modulation of fluorescent light: flicker rate and light source effects on visual performance and visual comfort". Light Res Tech 27 (4): 243–256.

• Colman RS, Frankel F, Ritvo E, Freeman BJ (1976). "The effects of fluorescent and incandescent illumination upon repetitive behaviors in autistic children". J Autism Child Schizophr 6 (2): 157–62.

• Turner M (1999). "Annotation: Repetitive behaviour in autism: a review of psychological research". J Child Psychol Psychiatry 40 (6): 839–49.

•  A J Wilkins, C D Binnie and C E Darby, Progress in Neurobiology 15,85 (1980).•  A J Wilkins, C D Binnie and C E Darby, and D. Kasteleijn-Holst Trenité,

“Inferences Regarding the Visual Precipitation of Seizures, Eye-strain and Headaches”, in M Avoli, P Gloor, G Kostopoulos, and R Nuquet eds. Generalised Epilepsy: Neurobiological Approaches, pp 314-326, Birkhauser, Boston, USA (1990).

•  J Hazell and A J Wilkins “A contribution of fluorescent lighting to agoraphobia”, in Psychological Medicine, 1990, 20, 591-596

• A J Wilkins, Nanno-Smith I, Slater A I and Bedocs L “Fluorescent lighting, headaches and eyestrain”, in LRT Vol 21 (1) 11-18 (1989).

References

•  D L Loe, K P Mansfield and E Rowlands “Light patterns and their relevance to spatial appearance and the quality of the lit environment” in Proceedings of the CIE 22nd Session, Melbourne (1991).

•  Rea MS. Light-much more than vision. Key note address. In: Final Report. The Fifth International LRO Lighting Research Symposium, Light and Human Health, November 3–5, 2002. Report No. 1009370. Palo Alto, CA: The Electric Power Research Institute; 2004.

•  Stevens RG, Rae MS. Light in the built environment: potential role of circadian disruption in endocrine disruption and breast cancer. Cancer Cause Control 2001;12:279–87.

•  Davis S, Mirick DK, Stevens RG. Night-shift work, light at night, and risk of breast cancer. J Natl Cancer Inst 2001;93:1557–62.

•  Hansen J. Increased breast cancer risk among women who work predominately at night. Epidemiology 2001;12:74–7.

• Hansen J. Increased breast cancer risk among women who work predominately at night. Epidemiology 2001;12:74–7.

References

•  Stevens RG. Epidemiological evidence on artificial lighting patterns and risk of breast cancer. Final Report. The Fifth International LRO Lighting Research Symposium, Light and Human Health, November 3–5, 2002. Report No. 1009370. Palo Alto, CA: The Electric Power Research Institute; 2004.

•  Schernhammer ES, Schulmeister K. Melatonin and cancer risk: does light at night compromise physiologic cancer protection by lowering serum melatonin levels? Brit J Cancer 2004;90(5):941–3.

•  Stevens RG. Lighting during the day and night: possible impact on risk of breast cancer. Neuroendocrinol Lett 2002;23(Suppl 2):57–60.

•  Rea MS. Light-much more than vision. keynote address. In: Final Report. The Fifth International LRO Lighting Research Symposium, Light and Human Health, November 3–5, 2002. Report No. 1009370. Palo Alto, CA: The Electric Power Research Institute; 2004.

• D L Loe, K P Mansfield and E Rowlands “Light patterns and their relevance to spatial appearance and the quality of the lit environment” in Proceedings of the CIE 22nd Session, Melbourne (1991).

Lighting, Health and WellbeingWalking the Tightrope

Jonathan Green MSLL AMILPeLight Solutions Ltd