"Go play outside!"
So said generations of mothers—at least once we got past the eons of history in which both work and play generally took place outdoors by default.
Partly, that motherly admonition was meant to get us out from underfoot, but there was also a high respect for the value of "fresh air and sunshine" for health and growth.
No one had to tell me twice to get outdoors, not when there were trees to climb and a forest to explore. I've been an avid bookworm ever since I learned to read, but I was happy to do much of my reading on the platform my father had built for us high in the trees.
When did the outdoors become our enemy?
Being exposed to the sun was branded a high-risk activity for children, unless they were slathered in sunscreen—not just at the beach, but in their own backyards. Even then, playing outside was not encouraged, for it provided no relief for mothers, who were told they had to keep their eyes on their children at all times, lest they get hurt, or even kidnapped. How much easier and safer it was to keep them indoors, entertained by the magic of that handy babysitter, the television set—the gateway drug of today's "screens."
However, the tide may be turning, at least a bit. Parents are once again at least thinking about trying to get their kids outdoor time. They are struggling to believe with their hearts the statistics that show kidnapping by strangers and mass shootings to be minuscule risks in most of the United States, and the discovery that children need a bit of danger and challenge to grow up both physically and mentally healthy. More and more people are realizing that the advice we were given for avoiding COVID—stay indoors, and especially avoid playgrounds, beaches, and neighborhood walks—was likely the exact opposite of what we should have been doing. Ever so slowly we are recognizing that our mothers, grandmothers, and great-grandmothers may have been right when they told us to go out and play. Fresh air and sunshine are indeed our friends.
Here's another reason why:
It is dark inside your head, but even there, the sun does shine.
This is the beginning of Heather Heying's latest substack post about the great value of Near Infrared Radiation (NIR), those wavelengths of light just longer than red.
Most people have heard of the hormone melatonin, known for its regulation of the sleep-wake cycle. This is created by the pineal gland, and is called circulating melatonin.
But there is also subcellular melatonin, which, it turns out, is produced in the mitochondria of our cells, stimulated by exposure to NIR.
Subcellular melatonin is a powerful antioxidant. ... Oxidation is a ubiquitous and destructive process in organisms, a natural side-effect of metabolism. Antioxidants scavenge the free radicals formed by oxidation, thus mitigating its deleterious effects. Melatonin is a particularly strong and multi-functional antioxidant.
In the brain, melatonin’s antioxidant capacity is likely to be especially important, both because of the disproportionately high use of oxygen by the brain, and because some other antioxidant systems are not present there. Absent near infrared photons being carried deep into the brain, which then promote the synthesis of subcellular melatonin, brain function might go more than a bit haywire.
Subcellular melatonin also reduces inflammation, increases the rates of waste removal within cells, and has immunoregulatory effects. Furthermore, it improves mitochondrial function via several known mechanisms, and generally promotes health and vitality. And again, there is substantial evidence that NIR prompts its formation.
So how do we get this NIR to our mitochondria? Here's the good news:
- The majority of photons that reach us from the sun are actually in the NIR range.
- Unlike visible and ultraviolet light, NIR penetrates deep into our bodies, including our brains.
- The bodies of babies and young children are perfused with NIR.
- Cerebrospinal fluid distributes NIR photons deep into the brain.
- NIR comes to us not only from the sun, but also reflected off objects around us, such as the moon, leaves, snow, sand—they can reach us standing in the shade, fully dressed.
- Just after sunrise and before sunset are particularly good times to pick up NIR.
- NIR is also produced by campfires, candlelight, and incandescent bulbs.
The bad news?
- Because our bodies are thicker, the average adult gets less than 2/3 the NIR penetration children do. Just what we need—another good reason to lose weight.
- Most of the lighting that we modern people experience indoors (fluorescent, LED) does not provide this vital nutrient.
You can read Dr. Heying's entire article, with a lot more, and references, here.
For those who prefer a non-print source, here's an excerpt from the latest DarkHorse Podcast episode (#170) in which she introduces the subject. (approximately minutes 25:34 to 39:32)