Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
12 Nov

How to Engineer a Successful Day of Sunbathing

SunbathingLast week, I walked you through the typical day of someone pulling out all the stops in the pursuit of a perfect night’s sleep. Today, I’m going to show you how to optimize the pursuit of another vital factor in our health: sun exposure. Unlike sleep, too much sunlight can hurt you if given enough time and the improper context. As much as we like to chuckle at the people scurrying for the shadows at the first hint of UV, and those that slather on 100 SPF sunblock at 5 PM, taking certain precautions and getting correct dosage is crucial. This is something I have to be particularly mindful of here in sunny southern California.

When we sunbathe, we’re trying to do several things at once. We want the vitamin D and all the other sunlight-related metabolites our bodies produce in response to UV-rays. Our eyes want the brilliant natural light to get our circadian rhythms aligned. The melanin-deficient among us often want to obtain and maintain a nice healthy tan. And we want to accomplish all these goals without damaging our skin and our DNA. This is crucial, because, except for white-skinned youngsters who don’t use sunscreen in the summer, most people are simply not getting enough vitamin D (via sunlight or supplementation).

So, what does your day look like?

You awake after the greatest sleep of your life, having gone to bed at the appropriate time. This is essential for successful, safe sunbathing, since our ability to repair UV-derived damage depends on a well-functioning circadian rhythm. If you didn’t sleep well or are running on a chronic sleep deficit, you may want to hold off on the sunbathing until you get your sleep in order as your skin won’t recover as well.

If you eat breakfast, you lay out an impressive spread of smoked wild salmon (or krill smoothie) and pastured eggs in butter. The salmon has astaxanthin, a photoprotective compound, as well as EPA and DHA, which have been linked to UV-protection. Omega-6 levels were linked to worse UV-protection in that same study, and pastured eggs have a better omega-3:omega-6 ratio than normal eggs. The butter is a good source of saturated fat, which offers more protection against sun damage than polyunsaturated fat.

You enjoy a large cup of coffee or a mug of good green tea (or both). Consumption of both coffee and green tea have been shown to increase UV-protection, probably due to both the caffeine content and the phytochemicals present in tea and coffee. Throw some pastured cream in that coffee for good measure if you have it.

You consider going out to sunbathe at midmorning when the sun is aslant, because as “everyone knows” the safest times to sunbathe are in the morning and late afternoon – anytime you can avoid the mighty and terrible midday sun. Luckily, you catch yourself and remember that UVA is highest in the morning and late afternoon, while UVB is lowest (nonexistent, even). Why is this a problem?

  • UVA penetrates skin rather deeply, passes through clouds, window panes, water, and ozone, and has been implicated in melanoma (the most serious and deadly kind of skin cancer) and DNA damage (PDF). And it doesn’t even make vitamin D.
  • Not only does UVA provide no vitamin D, it actually breaks down vitamin D by binding to the vitamin D receptor. Combined with UVB exposure, this is probably a mechanism for vitamin D regulation, but without the UVB, you’re just losing vitamin D.
  • UVA does not readily burn you, so you have no indication if you’re getting too much like you do with UVB.
  • We’re meant to get a balance of UVA and UVB together.

If you only have the morning (or late afternoon) available, go out and get sun anyway; some is better than none. The light exposure is important for your circadian rhythm, too.

For lunch, you enjoy a Big Ass Salad with a dressing made from something rich in monounsaturated fats, like olive oil or macadamia nut oil. MUFAs aren’t just oxidatively stable. They (or at least oleic acid) are also a precursor to oleamide, a sleep-inducing endogenous compound that may offer protection against the metastasis of melanoma cells. All the phytonutrients from the vegetables can’t hurt, either.

You grab that nice red you’ve been holding onto and slip it into your beach bag. Nothing like a glass of zin as you bask in the sun, plus the proanthocyanidines from grape seeds (which show up in red wine) offer photoprotection.

You nearly forget to pack a bar of really good, really dark chocolate with 85% cacao. Dark chocolate is rich in stable saturated fat while providing flavanols that help against UV damage. Note that the best quality chocolate with the highest cacao content will have the most protective flavanols.

It’s now right around noon, and the midday sun is directly overhead, your shadow nonexistent. It’s time to get some sun. UVB exposure, and thus vitamin D production, is at its peak (PDF). UVB burns, but it also tans (thus giving warning), and it doesn’t penetrate deep enough into the epidermis to trigger melanoma. At noon, you’re getting both UVB and UVA. UVB counteracts the UVA damage; UVA keeps the vitamin D synthesis from getting out of hand. If we upset the balance and get too much UVA without enough UVB, melanoma may result.

Now, before you go out, let’s figure how much time you need to spend. How much sun time you require for optimal vitamin D production depends on a few variables.

If you’re young, lean, and light-skinned, ten to fifteen minutes should be enough for vitamin D.

If you’re elderly, your skin probably doesn’t synthesize as much vitamin D in response to sunlight. You may need more time.

If you’re dark skinned, you need more time in the sun to make vitamin D. Those living in northern (or far southern) climes may need to supplement vitamin D to meet their requirements, as their ancestors likely evolved in warmer, more tropical climates with more intense sunlight.

If you’re obese, you won’t make and absorb as much vitamin D in response to UVB.

According to the Vitamin D council (link above), these groups may need about three times more sun exposure to hit regular vitamin D levels.

Information and plan in hand, you take a furtive glance around and remove as many articles of clothing as possible. Remove all your clothes if possible to increase exposure. Men, open your legs, prop a leg up on a chair while gazing off into the distance, or practice handstand splits – legend has it that exposing your testicles to the midday sun can actually increase testosterone levels. Maybe it’s the UV-B increasing localized vitamin D biosynthesis increasing testosterone production. Or maybe it’s the freedom, the sway, the breeze. Either way, I know I saw a link to the research previously. I’ll try to dig it up.

You lie down on the ground to optimize UVB exposure. Remember, part of the reason why we took over this world is our obligate bipedalism, which allowed us to move around without receiving the full brunt of the harsh African sun (it also explains why we evolved the fedora).

You stay in the sun until it stops feeling good. When the warmth turns to heat, you remove yourself. When basking turns to cringing, you get out of there or put some clothes on. When you can feel your skin burning, you’re too late. You won’t die or get cancer tomorrow because of it, but next time, get out before you reach that point. That burns are unhealthy is one of the things CW gets right.

If you want to stay out in the sun, put on some clothing or use a quality broad-spectrum sunblock (that blocks both UVA and UVB). Browse this post for non-toxic, full-spectrum options.

If you’re still around when late afternoon hits, you hightail it out of there or cover up. As the sun dips toward the horizon, UVB is waning and UVA remains. You don’t need any more UVA. U’VAd-enough! Get it? (Sorry.)

For dinner, you eat some Primal chili, or something else with cooked tomatoes, canned tomatoes, or tomato paste. The lycopene (which is far higher in cooked tomato products) will offer photoprotection. Insider tip: add a bar of dark chocolate to the chili just before serving for improved taste and UV protection.

Have some yogurt and berries for dessert. Apart from being a delicious treat, this is also a functional dessert that provides a specific probiotic – Lactobacillus reuteri – shown to increase vitamin D levels by almost 15 ng/mL in humans under controlled conditions (PDF). Even if you didn’t get enough UVB, keeping your gut healthy and colonized by specific probiotics will optimize your ability to synthesize vitamin D.

You’re sleepy, in a good way – sunbathing’ll do that to you – and you find yourself nodding off a bit earlier than usual. With more good weather forecast for tomorrow and a beach barbecue planned, you turn in for the night to ensure another night of excellent sleep and even better photoprotection.

As there are genetic components to sun resistance, this isn’t foolproof. But clearly, getting some sun is better than avoiding it altogether. If you’re going to get some sun, you want to stack the deck in your favor, and you could do a whole lot worse than a day like this.

Thanks for reading, folks. What did I miss?

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I have always joked that I am solar powered :) If I don’t get enough sun regularly I get grouchy. Luckily here in Santa Cruz we have lots of sunny days and I try to get on the water as often as possible- even in winter. I feel sorry for all those stuck in dark climates.

    Carter wrote on November 13th, 2013
  2. Would love to indulge in the glorious noon sun – but those of us with lupus suffer and risk a flare up of symptoms! any ideas??

    Hubbsie wrote on November 13th, 2013
  3. Happy me: I live in the sun capital of the US: Miami Nice

    wildgrok wrote on November 13th, 2013
  4. Interesting article! I didn’t know that about UVA vs UVB rays.

    The sun is confusing for me. Or more to the point, how much I need. I am very, very fair skinned and burn fast. But I also get seasonal depression and supplementing vitamin D helps tremendously (as in, I’m in my 40’s and last winter was the first ever without seasonal depression! Thanks D3 drops :) )

    So I don’t understand why my body needs sun but burns so easily. It’s just weird. I get more sun now than I used to, but mid day sun like that, I can maybe take 15 minutes and I can feel a burn starting.

    Shannon wrote on November 13th, 2013
  5. That’s really interesting Mark. I wasn’t aware of the impact our sleep had on our skins ability to recover from sun exposure. It makes perfect sense though.

    Thanks for the post :)

    – Trevor

    Trevor wrote on November 22nd, 2013
  6. Mark, this is such good stuff. I never believed the fear mongering, less than truthful dangers of sun exposure. I would like to make note that the UVB spectrum of light is highly susceptible to filtering. I believe that the sun needs to be at least a 50 degree angle in the sky before any UVB can filter through the atmosphere. After that moisture haze, dust particles and aerosol spray (weather modification high altitude spraying) can also work against UVB reaching the ground. I time my sun exposure by using the Navy’s “Sun or Moon Altitude/Azimuth Table” found at http://aa.usno.navy.mil/data/docs/AltAz.php to determine my best bang for my buck. Another note is that of time of absorption of the D3 produced on the skin. I believe It takes about 36 hours for complete absorption and that UVA light can destroy what is left on the skin from earlier exposures. Also washing with commercial soap and detergents can was off the cholesterol and D3. Washing with water alone will remove grime but will not wash off the D3. Time is required for absorption as mentioned earlier. The reason we call it sun “bathing” might be because the UV kills bacteria from the exposed skin, and body odor is a buildup of bacteria. Daily exposures to UVB keeps the supply going, but exposure to UVA only (early and late day, less than a 50deg. Elevation) will undo whatever remains on your skin. I live in San Diego County so I can expect 5 to 6 months of UVB presence. I am then reduced to supplementation. I prefer liquid spray D3 under my tongue to reduce possible digestive reductions of the D3. I’m on a strict budget after all. Or, as Mark mentioned in another article, I could lick my dog. I am afraid of scaring my dog though. I think he thinks I’m Hungary.

    Binktank wrote on February 19th, 2014

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