LED lights are now a primary light source and can be especially troublesome at night. LED’s with isolated blue light that’s not balanced by red light and near infrared light, are the worst offenders for sleep. They interrupt your all important circadian rhythms and mess with melatonin production. They are also linked to your body’s energy production and age related macular degeneration. But you can protect yourself.
Natural sunlight is made up of a broad spectral range of colors. During the brightest time of the day, blue light dominates, which signals your brain to be fully awake.
In the early morning, when the sun first rises, the slowly brightening daylight contains a lot of red and near infrared light. This signals your brain to increase activity and wakefulness. As the day gets brighter, the blue light component of the spectrum gradually increases. The red light during sunrise and sunset provides a kind of natural crossing from the night to the day and vice versa. There is little if any stress induced in the body by waking up to gradually brighter natural daylight.
Evolution has trained the brain to associate the presence of mainly blue light with the middle of the day and full alertness. Unfortunately, using blue light emitting devices such as LED lights in the evening will have the same effect on your brain. It thinks it’s still bright daylight, and melatonin production gets shut down. So do your chances of a good night’s sleep.
Dr Wunsch, a world leading expert in photo-biology, explains the details of this process in the video at the end of this post. Here’s a run-down of the main points.
The downsides of EMF (electro-magnetic field) radiation exposure from LED lights can lead to serious long term health complications.
In contrast, the beneficial aspects of near infra-red red are used in many medical applications today. It’s just outside the visible red part of the spectrum. With red and infra-red light you can feel the heat. Near infra-red is invisible, and you can’t feel it as heat.
Mitochondria produce energy in the form of ATP (adenosine triphosphate). Should that process shut down or fail for any reason, you’ve got about 15 seconds to live. That makes ATP production vitally important. And light and energy production go hand in hand. The long wavelength range of the spectrum where near infra red sits boosts the energy production in your mitochondria. Considering that many of the signs of aging are now associated with reduced ATP production and mitochondrial efficiency, that’s a major point to remember.
About a third of the ATP the body produces comes from food. The rest, two-thirds, come from long wavelength light exposure. And LED’s do not emit light in that range – hence the negative consequences.
With older, traditionally used incandescent lights, the intensity of the light can be dimmed. In LED lights, intensity is controlled in a different way, in a digital manner. Dimming and therefore color change is achieved via a process called pulse-width modulation. That means the LED switches on to full intensity, then switches off again, back and forth, constantly switching frequencies. You can’t see this with the naked eye but your brain notices the constant ‘flickering’ on a subconscious level. This same process also happens in your computer screens and televisions.
Your brain will filter out this constant flicker to achieve a steady image. But this process takes a lot of energy and explains why many people feel exhausted after a day of staring at a screen.
The light emitted from an LED is not the same quality as light from a natural source. LED’s consist of a blue LED light, and blue has the highest energy in the visible part of the spectrum. It causes oxidative stress. For tissue regeneration and repair we need the balance of the red and near infrared parts of the spectrum. Over exposure to predominantly blue light will switch the balance from repair and regeneration to damage and degeneration.
The type of light an LED emits does not exist in nature. This causes a stress to the body it isn’t used to deal with. Damage to the retina occurs, and the balance of your hormone system gets out of whack.
An incandescent light has a certain amount of spectral distribution – you know what you will get. LED lights however, can vary greatly in their spectral distribution. So there are worse LED’s and better LED’s around.
Sometimes, on the package, information is given about the colour rendering index (CRI) of the LED light. The least harmful LED’s are in the R9 range, which represents the red spectrum.
For example, the package may state a CRI of 95 with an R9 of 97 or so. This is the only sign for the customer that you have a high level or a high index for the R9. Sunlight has a CRI of 100. Incandescent light is Candlelight is 100. That’s the ideal.
A useful tool for evaluating healthy lighting is the colour temperature. There is the physical (natural) colour temperature, measured by heat (in degree Kelvin). This applies to sunlight, candlelight, fire light and incandescent and halogen light sources. Due to this type of light also being a heat source, it has natural limitations.
The other type is correlated color temperature. It is a calculated version. This means you calculate a lot until this light source might appear to the human eye in a similar way than a light source with a true color temperature of, let’s say, 2,700 degree Kelvin. This becomes a problem because you can tailor the color temperature however you want. Natural heat restrictions no longer set limitations.
This type of light source can appear to emit a warm light, similar to incandescent light, when in fact it is a cold bluish white light source. The additional red LED lights make the light appear warmer but it doesn’t fool your retina or your brain. The impact on your physiology is still the same as from a cold white source.
This is not so much a problem during the day, when your brain expects to operate under bright light conditions. In fact, if your office has windows the natural daylight streaming in will compensate for the high blue light component of your device screens.
Where it does become a major problem, especially for the quality of your sleep, is at night. And that’s because you produce melatonin not only in your penial gland, but also in your retina. So what can you do about that?
One of the best ways to reduce blue light exposure after dark is to switch back to incandescent light sources in your home. The ones with the transparent bulb are best, measuring at 2,700 degree Kelvin. These lights have barely any blue light at all in their color spectrum.
The other way to avoid blue light is to get a pair of blue light blocking glasses. These can be very inexpensively purchased for around $10. As soon as the sun sets, put on these blue blockers. Simple.
Alexander’s personal favorite for reading at night is a low-voltage incandescent halogen lamp, which is operated on a DC (direct current) transformer. Using DC eliminates dirty electricity and flickering. If you can adjust the output of the transformer between 6 and 12 volts, you get a color temperature similar to candlelight. This is the healthiest electric light you can get, and it’s more energy efficient than an LED.
Halogen lamps are indandescent and a lot more energy efficient than standard incandescent lamps. The low voltage halogen with the long wave lengths is the best option.
Wunsch goes into a lot more detail about the technical aspects of this in his interview with Dr. Mercola. So watch the full interview if you want all the physicist’s stuff 🙂
When using your computer (even in the daytime), try a program like f.lux or Iris to change the color temperature of your monitor. This can greatly limit another source of blue light.
There are a few other things you can do to improve your sleep as well. I have covered them here.
Wunsch emphasizes that it’s not the blue light coming from the sun itself which we should be concerned about. It’s the blue light, the high energy visual light, which comes from cold energy-efficient light sources. This is what causes the problem, not the blue light which comes together with longer wavelengths in a kind of natural cocktail. The danger comes from the light surrogates from non-thermal light sources.
If you want to be completely sure stay with the candles, or the incandescent lights.