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The Definitive Guide to Sun Exposure

Posted on May 28, 2020 By In Fitness With disabled comments

The ancients prayed to it. Farmers relied on it. The seasons depend on the earth’s tilt toward it. The sun is always up there, shining down, filling the world with light and heat, sending down powerful rays of energy that scatter across the surface, sneak through windows, penetrate otherwise dark caves. You can’t avoid it, unless you shut yourself inside, draw the blinds, and close your eyes.

That’s what we’re supposed to do: avoid it. “Any amount of sun exposure is unsafe,” according to the experts, and will give us skin cancer. They tell us it’s a toxin. If we have to be outside, we’d better slather on the sunscreen, wear a hat that shields our entire body, and avoid the harsh midday sun at all costs.

And yet, for hundreds of thousands of years of human evolution, we couldn’t avoid it all the time. We were exposed to the sun when we hunted, when we gathered. When we fished, dug, fought, climbed, and explored. The intensity of our sun exposure varied according to the climate, the latitude, the time of year, and we weren’t out there tanning, but it was always around. Exposure occurred to some degree on a daily basis. We are adapted to the sun, like most other life on earth. We aren’t just able to withstand it. We can derive vital benefits from our exposure to it. We need the sun in a direct way.

Today I’m going to tell you why we need sun exposure, what the benefits are. I’m going to tell you how to make it safe, how to avoid sun damage, and the best time of day to do it. I’ll discuss too much sun and too little. I’ll give you safe ways to block the sun and reveal the unsafe ways to avoid.

First, what’s so good about sunlight?

Benefits of Sunlight

The benefits of sunlight include:

  • Vitamin D
  • Nitric Oxide
  • Circadian Rhythm Entrainment
  • Immune Health
  • Cognitive Function
  • Eye Health

How does this all play out?

Vitamin D

Sun exposure causes the skin to produce vitamin D, a “pro-hormone” that regulates sex hormone production, immune function, bone, dental, and heart health, cancer prevention, and gene expression—to name a few functions. In other words, it’s one of the foundational compounds in the body, an extremely vital substance. We can get it from food or supplementation, but getting it from sunlight is auto-regulatory. It’s extremely hard to overdose on sun-induced vitamin D production, whereas you can overdo supplemental vitamin D (although even that is hard).

Nitric Oxide

Nitric oxide modulates the function of our endothelial system—the veins and arteries. Nitric oxide literally widens blood vessels and arteries, thus increasing blood flow to tissues (and the amount of nutrients that blood carries to those tissues). It even reduces blood pressure, improves our cardiovascular health, and is extremely important for our overall health, well-being, and physical performance.

It turns out that sun exposure increases nitric oxide production in the body.1

Circadian Rhythm

We need exposure to light at certain times of the day in order to regulate our sleep-wake cycle – our circadian rhythms. Without daytime/morning light, or with too much evening light, our internal clocks – and general health – go awry. Getting outside in the sun (even in winter) as early as possible is an effective and quite possibly necessary way to establish a healthy circadian rhythm. Plus, the more sunlight you get in the first half the day, the more resistant you will be to circadian disruption by artificial light at night.

Immune Health

Sunlight doesn’t just improve immune health by way of increasing vitamin D. It also has direct, immediate effects on immune function: increasing hydrogen peroxide production by and motility of T cells in the skin. T cells can use hydrogen peroxide to engulf and destroy pathogens, and increased motility improves their ability to move around and find pathogens to destroy.2

Cognitive Function

This study can’t determine causation, but high sun exposure is strongly linked to better cognitive function among Chinese elderly and we have reason to believe there’s a real effect here.3 For one, the vitamin D you produce in response to sunlight does boost cognitive function, particularly in the elderly (that’s been tested in clinical trials using vitamin D supplementation).astaxanthin, found in salmon and shrimp (and flamingo meat, if you can get it), may also offer protection against UVA.[ref]https://www.ncbi.nlm.nih.gov/pubmed/7591536’>7  Polyphenols in general tend to increase the skin’s antioxidant capacity, as do vitamins C and E.8 Anthocyanidins, found in red wine and berries, also protect against skin cancer.9

My picks? Berries, red wine, cooked tomatoes (tomato sauce, paste, ketchup), carrots, paprika, pastured egg yolks, sockeye salmon, shrimp form the basis of a good sun-resistance protocol.

Get early morning sunlight.

In a stunning example of the elegance of nature, early morning sunlight is rich in infrared light, which prepares your skin for subsequent UV exposure in the afternoon by enhancing its UV resistance.10 This protective effect of infrared light lasts for 24 hours, and it can come from either morning sunlight or an infrared light device, like a sauna.

Get the right amount of sun for your skin type.

Fair-skinned and red-haired? You need far less sun to get the vitamin D and other benefits you need, and you have far less leeway before damage occurs. Dark-skinned and living at a northernly latitude, like England? You might need to take supplemental vitamin D to get what you need.11 Even Indian men living in India may need at least an hour of sun to maintain optimal vitamin D levels.12

When is Sun the Strongest?

This is a common question, but it’s not really the right one. The sun is technically strongest at midday when it’s pumping out the most UVB and UVA rays. That’s also when you have the most potential to make vitamin D, which depends on the UVB content.

High UVB produces vitamin D, which protects against UVA-related damage and actively kills melanoma cells.13

High UVA in the absence of UVB promotes skin damage. Having both at the same time elicits a protective effect, or at least mitigates the damage of either alone.

So even though UV intensity is highest at midday, that’s arguably the safest time to get sun because it’s the best way to get balanced sun exposure.14 If you go mid morning or late afternoon, you’ll get too much UVA and too little UVB. Just make sure to get only as much midday sun as you need. For the lightest-skinned among us, 10 minutes of full body exposure at noon should be enough.

Skin Protection

The internal and lifestyle “sunblocks” detailed above form the foundation of your skin protection regimen, but sometimes you need actual sunscreen. The problem is that the majority of mainstream sunscreens use chemical UV filters rather than physical UV filters. What’s wrong with chemical sunscreens?

Physical vs. Chemical Sunscreen

Many sunscreens use UV-filters like benzophenone and oxybenzone for their UV-blocking properties, but they also possess a hidden feature: endocrine disruption. Certain forms of benzophenone, for example, inhibit the action of thyroid peroxidase, an enzyme necessary for the production of thyroid hormone.15 Another study showed that application of sunscreen containing benzophenone-2 for five days lowered T4 and T3 thyroid hormones in rats.16 Later, researchers examined the estrogenic effects of another UV-filter used in sunscreen—octyl-methoxycinnamate—and found that typical amounts were enough to disrupt hormonal function and exert other, non-endocrine health effects when applied to rat skin.17 That might not a problem if UV-filters in sunscreen weren’t designed to be absorbed into the skin, and therefore the body, nor if every expert weren’t telling us to slather a quarter cup full all over our bodies at the first hint of sunlight. But they are: the only way the chemical sunscreens work is if they are absorbed into the skin—and into systemic circulation.

Another downside of chemical sunscreens is that they’re selective screeners. They tend to block UVB while allowing UVA passage. This blocks the tanning/burning effect, but it also blocks UVB-induced vitamin D production. And the worst part? It’s not even effective against the development of melanoma! In fact, one study found a positive association between sunscreen usage and melanoma incidence.18

Meanwhile, physical sunscreens are broad spectrum: they block both UVA and UVB. They can be unsightly because they don’t absorb into your skin, but they offer the most protection with the least toxicity.

Sunscreen Ingredients to Avoid

These ingredients are absorbed into the body, show up in your urine, have estrogen mimetic effects, and can often cross the blood brain barrier and cause neurotoxicity.1920 Some of the most common include:

  • Oxybenzone
  • Benzophenone
  • Avobenzone
  • Octocrylene
  • Homosalate
  • Octisalate
  • Octinoxate

For a full list of chemical sunscreen ingredients to avoid, check out the data from this paper.

Sunscreen Ingredients to Use

There’s only one that I can recommend whole-heartedly: Zinc oxide. It reflects light, offers the broadest-spectrum UV protection, and cannot absorb into the skin. This is why it stays white and doesn’t rub in.

Nano-zinc oxide does rub in, but that also comes with a price. You absorb some of it. It appears to be less harmful than the chemical sunscreens, though not completely.

Non-Toxic Sunscreen Brands

These are ones that hit all the requirements.

Badger Balm – All their products are good, but the sunscreens are the most renown. They are very thorough with the science behind their sunscreens, and they run regular tests to confirm the safety of their zinc oxide formula. Best of all, they’ve managed to minimize the whitening without increasing the potential for toxicity.

Raw Elements Eco Formula – Active ingredient is zinc oxide. It’s thick, but stays on well even with water exposure and activity. Not too whitening, either.

Kabana Skincare – Another good sunscreen source that uses zinc oxide. They’ve even got a formula with added vitamin D, presumably to make up for the UVB you’re blocking. Not sure if that actually works, but it certainly can’t hurt.

Mexitan – They don’t just make non-toxic, zinc oxide-based sunblock. They also offer recommendations for beach resorts and produce safe self-tanner.

Okay, that’s it for today, folks. With summer right around the corner and the sun beginning to show, now’s the time to start getting smart, safe sun exposure—and after today’s post, I believe you are prepared to do so.

If you have any other questions, comments, suggestions, or concerns, leave them down below!

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