23 May Blue light and its impact on your health
Most of us are bathed in artificial light at home, school and work, and very few are blessed to watch the sunrise or sunset each day. Sunrise and sunset have a distinct red/orange tinge of colour, while the midday sun has more of a blue colour and the combination of this form of full spectrum lighting has provided the perfect balance to manage our circadian rhythm throughout the course of evolution. Digital devices and the new generation of cell phones and lighting, changed all of that.
Four in ten Australians have sleep disorders and the annual cost to the Australian economy in lost work productivity is estimated at $17.9 billion (Economics, 2017).
Digital devices and cell phones fitted with LEDs emit a very large amount of blue light and very little red light. When you use a digital device such as your smart TV, smartphone and tablets first thing in the morning, you are effectively telling your body that it’s midday, thus confusing your circadian rhythm. When used at night, it suppresses the sleep hormone melatonin, which contributes to sleep-related disorders, changes to the circadian rhythm, and compromises your ability to regenerate every cell in your body (Hanifin and Brainard, 2007; Thapan, Arendt and Skene, 2001). It is not a coincidence that the incidence of sleep disorders significantly escalated since 2010, with the introduction of digital devices (Adams, Appleton, Taylor, McEvoy, & Antic, 2016). As melatonin is nature’s most potent anti-cancer agent and anti-oxidant, suppressing melatonin significantly increases the level of oxidative stress in the body which is what causes ageing and chronic disease, and age-related macular degeneration (eyes). This is why lack of sleep has significant downstream effects on your physical and mental health, mood, memory and concentration. But it’s not just digital devices; indoor artificial light such as bedroom lighting, are just as important to control. Exposure to just 40 lux of blue light is sensitive enough to impact circadian rhythms, while red light does not cause any melatonin suppression (Figueiro and Rea, 2010). In addition, children are twice as sensitive to blue light exposure resulting in melatonin suppression compared with adults (Higuchi et al., 2014), so it’s important that children do not use digital devices after sunset.
The American Academy of Sleep Medicine have listed the ideal sleep time for children as follows (Paruthi et al., 2016):
- Infants (4-12months) require 12-16 hours sleep
- Children (1-2years) require 11-14 hours sleep
- Children (3-5years) require 10-13 hours sleep
- Children (6-12years) require 9-12 hours sleep
- Teenagers (13-18years) require 8-10 hours sleep
To reduce exposure to blue light:
- Avoid using a smartphone, television and digital devices after sunset and for at least one hour before bed.
- Use ‘red’ light at night for indoor lighting by replacing the compact fluorescent light bulbs and LED lights with halogen lights (incandescent or downlights) or incandescent lighting such as the OLED battery operated candlelight from IKEA.
- Use blue-light blocking glasses which are amber/orange spectacles.
- Cover your skin at night, as it is the largest organ in the body that absorbs light
- If you need to use a digital device or smart phone at night, install a blue light filter App.
- To entrain your circadian rhythm, watch the sunrise and sunset as often as you can.
Adams, R., Appleton, S., Taylor, A., McEvoy, D., & Antic, N. (2016). Report to the Sleep Health Foundation 2016 Sleep Health Survey of Australian Adults: The Adelaide Institute for Sleep Health: University of Adelaide.
Economics, D. A. (2017). Asleep on the job. Costs of inadequate sleep in Australia. Retrieved from http://apo.org.au/node/101971
Figueiro, M. G. and Rea, M. S. (2010) ‘The effects of red and blue lights on circadian variations in cortisol, alpha amylase, and melatonin.’, International journal of endocrinology. Hindawi Limited, 2010, p. 829351. doi: 10.1155/2010/829351.
Hanifin, J. P. and Brainard, G. C. (2007) ‘Photoreception for circadian, neuroendocrine, and neurobehavioral regulation.’, Journal of physiological anthropology, 26(2), pp. 87–94. Available at: http://www.ncbi.nlm.nih.gov/pubmed/17435349 (Accessed: 2 July 2018).
Paruthi, S. et al. (2016) ‘Recommended Amount of Sleep for Pediatric Populations: A Consensus Statement of the American Academy of Sleep Medicine’, Journal of Clinical Sleep Medicine. American Academy of Sleep Medicine, 12(06), pp. 785–786. doi: 10.5664/jcsm.5866.
Thapan, K., Arendt, J. and Skene, D. J. (2001) ‘An action spectrum for melatonin suppression: evidence for a novel non-rod, non-cone photoreceptor system in humans.’, The Journal of physiology. Wiley-Blackwell, 535(Pt 1), pp. 261–7. doi: 10.1111/J.1469-7793.2001.T01-1-00261.X.