IOS 590: Apps for Your Next Outdoor Adventure

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What are your thoughts about today’s show? We’d love to hear from you!

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Re: Mikah’s comment about the risks tick season: I completely agree. About 5 years ago, we got some clothing from Insect Shield; we’ve been very happy with it. This company treats clothing with permethrin. It’s a close chemical cousin to permethrum, a natural insecticide produced by chrysanthemums. Permethrin-treated clothing is used by a variety of workers who regularly work in the brush.

Insect Shield treats clothing for a variety of outdoor vendors like LL Bean; they use that trade name so people can identify their product. Insect Shield also sells their own stuff: clothing for humans and a small number of products for dogs. Finally, Insect Shield will treat your own clothing at their facility in Greensboro, NC. They’ll do single items of clothing or will do prepaid packages you stuff into a FedEx envelope. I’ve never used their clothing treatment service, but I’m guessing it works as well as new clothing treatments. I have no feedback for their pet treatments. The treatment lasts for ~70 washes; you should use treated clothing only when needed. Sorry, @RosemaryOrchard, I have no idea what permethrin clothing or treatments are available outside of the US.

There was also a comment about using sunblock when going outside; that picture is more complicated than it seems. One mystery is why cancers (including skin cancer) have become more prevalent in the last 30 or so years – while we are also spending far less time outdoors. Recently, science has provided a possible explanation: about half the energy from the sun is in the infrared (IR) frequency range, and IR light is used by our mitochondria (!!!) to produce the antioxidant melatonin. In short, cancers may be increased because we are not getting enough good (i.e., IR) sunlight. This new science is discussed in a MedCram video: Sunlight: Optimize Health and Immunity (Light Therapy and Melatonin) - YouTube . The Zimmerman science paper discussed in that video is available at Melatonin and the Optics of the Human Body | Melatonin Research . Findings noted in the video and referenced documents:

  • 95% of our melatonin is produced (and used) in our mitochondria. The melatonin is used as an antioxidant; more free radicals (i.e., reactive oxygen species) production happens when the cell is active. The energy source used to power melatonin production is NIR light from the sun. This IR radiation can travel several cm through our skin to a large percentage of our cells (including our brain cells). Water may be used as a medium to transfer that IR to deeper cells (see this science text for more info).
  • Our pineal gland produces 5% of our melatonin, which is distributed in our bloodstream. This source is distributed at night.
  • Cueing the pineal to produce melatonin is a critical function with separate light-sensitive cells in the retina that send their signal to the suprachiasmatic nucleus (SCN). Light after sunset confuses this day/night synchronizing mechanism (and, I’m guessing, messes with the pineal’s ability to reliably generate nighttime melatonin). Nighttime-lighting adaptations to our OSs is good, but even a dim night-adapted screen is still interfering with this light-sensing mechanism.
  • By spending less time indoors, adopting IR-filtering glass in our homes and businesses, and changing to narrow-spectrum LED lighting in our homes and businesses, the daytime melatonin-generating ability of our mitochondria has been severely compromised. The extent and severity of this chemical deficiency is not well known. Visible-spectrum LEDs are part of the problem, but LEDs can be adapted. There are all sorts of NIR LEDs used in “Red Light Therapy” appliances.
  • Antioxidants produced by regular IR radiation protect us from free radicals generated by UVA and UVB radiation. The MedCram presenters note that people who only occasionally get out in the sun have higher rates of skin cancer than those who are regularly outdoors. I’m not saying to avoid sunscreen, but our understanding of the risks of sunlight is more complex than we thought a few years ago.
  • Author Scott Zimmerman has a small company Silas in NJ (I couldn’t locate a website). Silas’s business is full-spectrum bulbs; there was an unfunded kickstarter in 2020. That doesn’t mean the science paper is invalid – Zimmerman clearly has a passionate interest in full-spectrum lighting tech.

The big take-aways are decidedly low-tech:

  • Get outside as early as possible after sunrise.
  • Get outside as much as possible during the day. IR light is reflected by plants; walking through woods provides nearly as much IR as being in direct sunlight.
  • Artificial IR radiation (saunas, “Red Light Therapy” appliances, wood stoves, etc.) is optional but highly useful. Shifting [back] to lighting that provides more IR than our current visible-band-only LEDs sounds like an excellent idea. They will be less “efficient”, but that’s begging the question.
  • The tech for measuring melatonin levels in our mitochondria (and, hopefully, our understanding of this phenomenon) will continue to improve. We need more science, and more beautiful visualizations from vloggers.

One semi-related item to the IR story: UV-A radiation does nothing good for our bodies, but [a particular frequency] of UV-B radiation produces Vitamin D in our skin. When the sun is low in the sky, none of the sun’s UV-B will get to the surface of the earth. “If your shadow is longer than you are, your shadow will get UV-B – but you won’t.” Apps like DMINDER note the daily and seasonal geometry of the sun to note when sufficient UV-B is available. The UK gets essentially zero UV-B for a large part of the year. In short, most of us need to supplement with Vitamin D3 ensure abundant amounts. Further, the US RDA for Vitamin D3 (600 IU) is woefully inadequate. This paper notes that 5000 - 10000 IU (125mcg - 250mcg) of Vitamin D3 per day is both safe and necessary for most to get up to optimal blood serum levels of 50 ng/mL – and please talk with your doctor.