Another post to file under “all the rays are actinic”:
[Near infrared light] can trigger cellular activities that restore cellular metabolism, promote blood flow, neuroprotection, and reduce levels of inflammation and oxidative stress. All of these cellular mechanisms can be summed up as “helping the brain to repair itself.”
I observed years ago that the more sunlight I got the better I felt. Although “it’s the vitamin D” seemed like a reasonable hypothesis, I’ve been pretty careful not to just assume that—whenever I’ve written about this I’ve gone ahead and listed some of the other “active ingredients” that tend to come along with sun exposure—exercise, time in nature, etc. As I look into the matter more, I find there’s a growing body of evidence that sunlight itself does provide benefits, but it’s not just the UV light—the other frequencies of light are also actinic in all kinds of ways.
We’ve long known that blue light (especially, but not exclusively, a specific frequency of blue-green light absorbed by a pigment in the eye called melanopsin) was critical for establishing and maintaining an appropriate circadian rhythm. Very recently we’ve discovered that adipose tissue expresses the genes that produce the same pigment and use it to vary how the cell acts. In particular, after exposure to an amount of blue-green light that might shine through skin exposed to full sun, fat cells reduce the amount of fat they store, and also produce less leptin (a hormone that affects feelings of satiety).
As I discussed a few weeks ago, there’s been a lot of research on the effects of red and near-infrared light exposure. Here’s a page with links to a bunch of studies that suggest that red and near-infrared light boosts collagen synthesis, speeds healing of burns, incisions and broken bones, reduces inflammation, and generally reduces the effects of aging on your skin.
I guess that leaves us with orange and yellow light unaccounted for, but I don’t doubt that they’ll turn out to be actinic as well.
For most of my adult life I carefully limited my sun exposure. More recently—after discovering that the more sun exposure I got the better I felt—I’ve been trying to get as much as I could without getting burned. Just lately I’ve been groping towards something more nuanced.
Back in maybe the 1980s I briefly tried to follow the advice of dermatologists to never go out without sunblock. That didn’t work well—inevitably there would come the day when I was out in the sun longer than anticipated, and (not having built up a protective tan) I’d end up burned.
After that, for a decade or two, I came up with some simple rules: Unlimited sun before 8:00 AM and after 5:00 PM, but I’d aim to get 20 minutes of mid-day sun. If I was going to get more than that, I’d wear sunblock, but I tried to get that much sun every sunny day. That worked pretty well—I’d get enough of a tan to provide some protection on those days that I was unexpectedly out in the sun.
That schedule, of course, fell out pretty much automatically from working at a regular job. I stuck with it even after I wasn’t working at a regular job because it worked pretty well.
For various reasons, such as needing to take very long walks to train for our big Kal-Haven trail walk, I started spending more time out in the sun, and began to observe that the more time I spent in the sun the better I felt, leading me to get what was probably more sun than is really wise.
Since recently running into the idea that certain frequencies of red and near-infrared light are good for your skin and deeper tissues, I’ve been prompted to think about all this in a more systematic way, and have been trying to come up with a plan that maximizes the benefits while reducing the harm caused by sun exposure.
I’m still in the research stage, but here are the early changes that I’m making:
First, I’m reducing the amount of mid-day sun I’m getting. I’ve been going for around 40 minutes (as much as I can get without risk of burning), but I’m bringing that back to around 20 minutes. Still enough time to make plenty of vitamin D.
Second, I’m replacing that 20 minutes of mid-day sun with 20 (or more) minutes of sunlight during the period that the UV index is between 1 and 3. (This time of year, where I live, that’s maybe 7:30 AM until 9:00 AM.) My hope is that part of the reason more sun makes me feel better is the red light (rather than the UV), and that morning and evening sun can provide those frequencies.
Third, I’m trying to get some very early (dawn) sun exposure. This is specifically for the effect early morning light has on the circadian rhythm.
Only in the middle of writing this did I realize the extent to which I’ve come back to what I did for most of my working years—except that instead of having to squeeze my morning sun exposure into the time I spent crossing the parking lot, now I can extend it to 20 minutes or longer, and combine it with a proper walk in nature for some sweet, sweet vitamin N.
I went for a long-for-me, 7.22-mile run this morning, and listened to a podcast about light therapy.
(I go back and forth on listening to podcasts during runs. When I listen I feel like I miss out on being fully embodied in my physical activity. When I don’t listen I fall behind on stuff I really want to listen to. Today I listened.)
The podcast had Paleo Magazineʼs Ashleigh Van Houten interviewing Scott Nelson, the founder of Joovv, talking about the health benefits of exposing your skin to red and near-infrared light. I’d heard about this, but had assumed it was some woo-woo new-agey thing. Turns out it’s probably not. There’s been a huge amount of research on the benefits of exposing your skin to red light in the 660-nanometer and near-infrared light in 850-nanometer range.
(There was apparently a lot of research funded by NASA back in the 1990s when they had to use lasers to get light of just the right frequency. Nowadays LEDs make it easy to get the intensity and frequency of light that you want.)
So, I’m out on my run, listening to Ashleigh and Scott talk about all the health benefits to your skin (of the red light) and to deeper connective tissues (of the near-infrared) and thinking that it all sounds really cool, but knowing that I’m probably never going to want to spend even hundreds, let alone thousands, of dollars to buy a device that will shine bright red light on my skin.
At around the mid-point, maybe 4 miles into my run, I paused for a drink of water out of the fountain in Morrissey Park, thinking it was pretty hot for just 8:40 AM . Which made me think of this giant glowing orb in the sky, which was shining down on me with pretty intense light at a wide range of frequencies, most definitely including red and near-infrared.
Turns out, sure enough—the energy in the red and near-infrared frequencies of sunlight is right in the range of therapeutic doses shown to have health benefits.
Of course, full sunlight is full of other frequencies of light, including blue (prone to mess up your circadian rhythm if you’re exposed too close to bedtime, but just what you want to get your circadian rhythm set correctly if you get your exposure in the early morning like I was doing), and ultraviolet (dangerous in excess, but the UV index was zero when I started my run at 7:40 AM and probably didn’t reach 5 before I was safely back indoors). So you need to treat sunlight with respect. But I already knew that.
I have mentioned before that I feel better when I spend a lot of time outdoors, and have speculated that sun exposure is part of the reason. (Along with time in nature, moving more, appropriate quantities of community and solitude, etc.) The information about red and near-infrared light exposure seems to lean a bit in the sunlight direction—but with the welcome news that it’s not just the vitamin D that helps make me feel better, which means maybe I can feel great without having to expose myself so much to the deadly actinic rays of the sun.