LED Astray
One of the major domestic transitions to a more energy-sparing life has been to swop all our old incandescent light. bulbs to low-power Light Emitting Diodes (LEDs). In offices, the fluorescent tubes that were ubiquitous have now been changed to lights with LEDs. The energy savings are considerable; a 10watt LED is sufficient to replace a 60watt incandescent bulb, for example, and of course the LED bulbs have a longer lifetime, so less servicing, less waste.
This is a win for sustainability and is one of the essential measures we need to take along the path to carbon neutrality. There is one tiny dark cloud on the horizon, however, and that is that unlike incandescent lights, LEDs are potentially damaging to your health, The reason has to do with the wavelengths emitted by LEDs, which are mainly short wavelength light in the visible spectrum, 350 – 650 nanometers (nm), typically peaking around 450 nm. Incandescent light, by contrast, is broad band (300-1400 nm) and sunlight even more so (300-3000 nm at ground level).
Representative spectra of a White LED, Compact Fluorescent (CFL), Incandescent bulbs and the AM1.5G standard solar spectrum (typical for mid-latitude annual sunshine).
Figure courtesy Ian Mathews
Minute sausage-shaped organelles called ‘mitochondria’ are the power-plants of our cells. Mitochondria are light-sensitive and thrive in long wavelength light that we cannot see – infrared light – but go into decline when exposed only to the shorter wavelengths typical of LED lights. Thus, if we are house-bound or live and work indoors under LED lights, which deliver no light in the infrared range (700nm and above), this absence of long wavelengths will degrade the performance of mitochondria, which have critical functions in regulating metabolism, disease and ageing. A lack of frequent exposure to infrared light thus has wide negative consequences for health.
Mitochondrion 'working from home'.
Since infrared light penetrates through our bones and body, even when fully clothed, all our mitochondria are exposed to infrared wavelengths in sunlight and incandescent light. The bottom line is that if we want to keep our mitochondria in peak condition, the solution is not to revert to incandescent lighting, but to expose ourselves regularly to natural light. Even on cloudy days we can give our mitochondria a sun bath of infrared light. Is this why the NRNs plant-propagators, meadow-makers, hedge-planters, birders, water-testers (and Eynsham’s dog-walkers) look so happy, healthy, and youthful?
Mitochondrion sunbathing.
If you want to read more about the wonders of mitochondria and the importance of light for their function, take a big breath for a deep dive.