We talk a lot about exposure to full daylight or replacement light therapy lamps during the day and avoiding the blue end of the light spectrum during the evening. Normal full spectrum sunlight wakes you up and produces serotonin that then helps produce melatonin later when light exposure stops. Daylight also raises many other alerting substances and makes you more active. This helps make you more tired by evening and likely to fall asleep on time if you stop light exposure soon enough.
While most research and treatment for sleep and mood disorders has concentrated on replicating visible light we are beginning to realize the invisible or barely visible far ends of the light spectrums have the potential for greater effects on our bodies than the light we can see. As we tend to spend less and less time exposed to actual sunlight researchers are increasingly finding benefits to including light beyond the visible light typically used to light our homes. Light through windows does not count because they block the far ends of the light spectrum.
UV may be difficult to utilize safely and is not included in light therapy lamps but a newer, safer addition to "light therapy" is using infrared light. The opposite of the bluer or UV end of the spectrum. Rather than waking you up like full spectrum or some blue light sources do infrared has the potential to put you to sleep. Studies in people are limited so far but have shown increased melatonin production, individuals reported feeling better rested, and it potentially made it easier to get up the following morning with less of that lasting drowsiness.
Some people have started placing infrared or NIR (near infrared) bulbs near their bed or where they spend their evenings. They use those as their light source for anywhere from 30mins to several hours at the end of the day depending on strength, spectrum range, and individual sensitivity. It needs to be actual LED infrared bulbs and not just red tinted incandescent heat lamps or similar. Generally those I talked to or found posts by said they are using little clip on or desk lamps with led bulbs around 18-30watts placed a few feet (~1 meter) away. The 600-700nm range is being used by itself for sleep/mood disorders with 650nm the most common. Some are combined with 850nm (not visible light) for broader effects. Any quality bulb should be labelled with the range.
After doing my own research into infrared I have been testing a higher wattage panel (54w) that includes some 630nm as well as 650 and 850 and it is blindingly bright. I wanted the strong, wide range infrared to help with mysterious muscle aches and inflammatory symptoms. This light has a 15min max timer to reduce the risk of harming yourself or overheating the light. In order to also test it for sleep improvements I placed it on a shelf a short distance away at head height and laid it pointing up. That way I could only see some residual light that brightened the whole room. I had to keep turning the timer back on to get 30-60mins of light exposure per evening.
I haven't used it for long yet but the 5 nights I did showed improved deep sleep on my oura ring sleep tracker, I felt better rested, and I got a LOT more done the past few days without getting fatigued as quickly and recovering better from the previous day's activities. I had to wake up 2hrs earlier today and found it surprisingly easy compared to usual.
I have also been using the panel as intended at closer proximity to my legs and back for 5-15mins a day. It is hard to say which is contributing the most to my sudden increase in motivation and getting those various things I'd been neglecting done recently. Infrared has potential for treating sleep interruptions due to chronic pain or inflammation as well as general insomnia.
I will probably buy one of the cheaper, lower wattage clip on lamps to more easily leave it running for longer in the evening. Then I can better test if merely exposing myself to infrared light in the room is improving my sleep and energy.
For those that want some sources of info and more technical reading here are some of the studies I found and some explanations of infrared and it's benefits. Aside from actual studies and first hand accounts from people I've been talking to it's been difficult to find articles that summarize the useful info into easier to read form.
This is one of the small studies often referred to by other info sources. Researchers exposed 20 basketball players to 30 mins of infrared every evening for 14days. They tested melatonin levels and had them answer a sleep quality questionaire. The result was increased melatonin and positive improvements in perceived sleep. ncbi.nlm.nih.gov/pmc/articl...
Research article on melatonin, some related body systems such as glutathione (important for removal of waste products and toxins as well as reducing inflammation) and how some ranges of infrared light impact these in the body.
Study on mice testing various intensity of red spectrum and normal white light. The results were that enough red light triggered sleep behavior with improved sleep and more consistent sleep patterns. Introducing white light altered sleep architecture and reduced the quality of sleep.
I am not recommending this as a source to buy from but their site has good detailed explanations on the function and impact of infrared on the body with a page devoted to sleep benefits.
Personal blog type article from School of Calisthenics in Nottingham on the benefits they see using one company's infrared lighting products schoolofcalisthenics.com/20...
A short post by a company that researches light usage for various health benefits announcing a research study they were planning to run last winter and the benefits noticed with infrared light so far. I'm not sure if they have the results published yet of their study.
Incandescents have an extremely limited light range. We use nanometers when talking about a single specific wavelength of light and kelvin temperature (simply "k") when discussing the entire color range displayed by a light source. If we ignore specialty lighting with odd or extreme wavelength combos then overall the lower the k rating the yellower it is with less blue. The higher the k rating the bluer it is. Balanced white light is in the middle. The closest approximation of visible sunlight spectrum or the purest white light is considered to be about 6,500k with down to 5,000 also getting labelled as "daylight" or "sunlight" bulbs. This range includes majority of visible red, yellow, green, violet, and blue light. Around 10,000k appears slightly bluish and is sometimes used for light therapy, fish tanks, or growing plants.
An incandescent bulb can only give off light in the range of 2,700k. All alteration to color of an incandescent is done by coloring the glass. Clear glass bulbs sold for using in room lights is only yellow and even blue tinted glass may not produce the exact wavelength of blue that triggers our brains because it simply doesn't exist in the bulb to start with.
Despite the yellow appearance the actual light waves given off look like this
Incandescent is actually closer to infrared than newer lighting and some argue for the benefits of using the old incandescents for house lighting. Such as the site that pic is off of hollandfranklin.com/incande... .
I don't entirely agree since we do need exposure to all spectrums of light to be healthy. Some ranges of UV contribute to skin health rather than damage and is required to produce vit d. Many need brigh lighting with lots of blue to avoid depression and lack of alertness during the day. Not triggering wakefulness and things like serotonin production while awake leads to more problems at night. If you can't get outside and you install only incandescents in your house you will completely lack exposure to all beneficial light ranges.
The issue is the timing of those spectrums is important. Normally the sunrise and sunset produces a change in light wavelengths throughout the day with the highest blue and UV right before the middle of the day, more red and infrared in the evening, and then you have almost complete darkness. What dim bluish light there is at night is not of the wavelength that promotes wakefulness and too dim to trigger that reaction.
Even if you don't use incadescent bulbs most room lighting has a minimal effect on sleep for most people unless you keep your rooms very bright. Humans see best in yellow to green light. That's why an incadescent doesn't look reddish despite the light range it gives off. Daylight spectrum can actually appear dimmer because you can't make use of the extra blue and these bulbs often get described as "harsh" lighting. Most bulbs sold for room lighting are around 3,000-4,000k with minimal blue.
If you are extra sensitive to lighting or do purposefully use daylight spectrum fluorescent bulbs, led lights, or prefer lots of lighting in your house it may produce enough blue or just overall light to interfere with melatonin production and sleep. It would be best to use dimmer, alternative lighting in the evening.
Usually the major and possibly only exposure to blue light after daylight hours is led or lcd light sources that are mostly only found in electronics. Most devices now include a blue light filter option or there are apps you can install to get rid of the blue. Usually it comes with an automatic schedule that turns on at the same time every evening. There are also blue blocker glasses that filter the wavelength of blue that causes sleep problems. Blue light filters of any type will make everything appear reddish so it's an issue if you try to watch evening tv but it doesn't really effect reading.
I have tried both the blue filter glasses and the phone filters that hold back the blue pixel. At the moment I prefer the glasses.
You are right in that the wavelength of light matters and that the spectrum of incandescents does vary. However, an incandescent will go to the shorter end of the visible octave as well as the longer end although the balance will vary.
I have also used a UV light to generate vitamin D. I don't have really good quantitative results on that, but it did appear to work.
Looking straight at a screen will most definitely have a negative effect on sleep triggers and melatonin production even in a room full of incandescent light. It has been shown that even small exposure to electronic screens before bed in a variety of lit or dark rooms has negative effects in countless studies. Some people are more sensitive to this effect than others. Some people in light studies report feeling like they got a normal amount and quality of sleep despite the negative effects researchers saw on sleep triggers prior to attempting sleep. Majority in this section of this website probably don't fall in that group who can ignore light triggers.
If you do respond strongly to blue light you can't cancel it out with incandescent lighting because at amounts to easily see in a room it actually does suppress the sleep response. It does not increase it at higher exposure levels like NIR and infrared by themselves will. You have to scroll way down this study that got really boring to read to see the measurements from incandescent light used instead of just their summary of what daylight spectrum fluorescent did. They were mostly looking at the negative effects of incandescent only lighting on daily performance and benefits of daylight spectrum fluorescent bulbs on daytime reaction speed, wakefulness, and cognitive ability. They also tested melatonin and took sleepiness questionaires to try to find the cause of the reduced mental abilities when kept in incandescent light.
They used 60lux of incandescent. That's equal to about 50watts in a 144sq ft or 13 sq meter room. This study mentions a 100lux room as brightly lit and another study considered 200lux to be a brightly lit room and less than 5 lux to be a dimly lit room so we are talking a moderate level of light exposure potentially slightly below that of typical daytime lighting in a room. The exposure to incandescent in the study increased wakefulness, increased the time it took to sleep, and reduced melatonin production. It just did so a whole lot less than a 6500k fluorescent bulb.
If you look at the graphs in the study it shows sleepiness initially dropped when exposed to incandescent light and then went up much slower than it did without light exposure. While melatonin increased by 40% more in the presence of incandescent compared to fluorescent lighting it still increased less after light exposure than without light exposure.
Incandescent light can't counter the effect of blue light if it exerts some of those same effects itself. Very dim incandescent light may have some of the benefits sites mention of actually increasing melatonin but too much visible light still has a negative effect. Incandescent merely has less negative effect than other forms of light due to it's high red and low blue spectrums and potential positive effects at dim light levels IF there is no other visible light to interfere. It still has yellow and some blue light that at brighter levels ends up negating it's own positives when we are talking increasing sleepiness and melatonin. At a certain level of brightness incandescent light will only contribute to the effects of blue light from electronics so it's ability to negate it is at best limited to only very low levels of blue light with very dim incandescent lighting.
Even if you use infrared instead of incandescent while still using your electronics you aren't eliminating the blue or visible light exposure. You are only adding more NIR and invisible red spectrum so the result would probably end up much like the incandescent. If all light levels are dim the NIR can provide benefits for sleep but at some level of blue or visible light brightness it would begin to interfere with sleep again. We don't know what that level is. It might take only a phone or it might take a large tv to produce enough light to cancel some of the benefits of NIR. My personal experience is that I used the 54watts of NIR indirectly while still sitting in front of dual 19" computer monitors and had benefits from it so it may have a lot of potential.
One thing to keep in mind is things that have an opposite effect on the body don't always negate each other. Sometimes one simply overrides the other and the body ignores one of the 2 options. Such as if exposure to blue light and infrared resulted in the brain only reacting to blue light even if there was a lot more infrared. This does seem to possibly be the case at a certain level of blue or visible light exposure. If other light is bright enough the brain stops responding to the infrared portion.
Other times something unexpected happens. Perhaps the blue light triggering alertness and activity could end up causing the infrared to trigger a much greater production of ATP than it normally does when not also exposed to alerting triggers. The resulting boost of energy could make sleep even more difficult but be extremely beneficial for daytime use, athletes, and chronic fatigue sufferers. Who knows.
I've been learning about the health benefits of infrared light therapy for 2 years now but never took the plunge of purchasing one. Your post is a bit older but can you share an update on its usage. Has it improved your sleep? Are there any other health improvements that you experienced? Also, can you share the brand that you're using? I've seen a few on Amazon. Thanks
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