Last year for our anniversary we'd been going to Miami a few years running. They were calling for rain all week. So at the last minute I looked at the one place I know sunshine is close to guaranteed, and we rebooked the flights and the hotel for the desert.

When Annette and I started hunting for land where we could invite people into something transformational, one ingredient had to be all but guaranteed. Sunshine. We searched the country for the sunniest ground we could find, and Arizona kept winning. Yuma holds the world record at roughly 90 percent of possible daylight, and the northwest corner where we landed is right behind it.

Why chase sun that hard? Because it does far more for you than it gets credit for.

Every one of those starts the same way.

Eight minutes and twenty seconds ago a particle of ultraviolet light left the surface of the sun. It crossed 93 million miles at 186,000 miles per second, and right now it's landing on your forearm.

In the outer layer of your skin sits a molecule called 7-dehydrocholesterol. Your own cells built it and put it there. It doesn't help you feel, or heal, or hold water. It waits for one kind of light: ultraviolet B, between 290 and 315 nanometers.

When that photon arrives the molecule absorbs it, and the energy snaps a single bond in a ring of carbon atoms. The ring opens. Your body heat rearranges the pieces over the next day or two. Your liver adds something. Your kidneys add something. What comes out is a hormone called calcitriol, and it binds receptors sitting directly on your DNA that decide which genes get read out loud and which stay quiet.

One bond breaking in one molecule. Two hundred genes.

Michael Holick spent decades mapping that pathway. A whole-body dose of summer sun, the amount that just barely pinks your skin, is worth 10,000 to 25,000 international units of vitamin D3. A typical capsule gives you 400 to 1,000.

Your skin also knows when to stop. Once enough precursor piles up, more sun converts the surplus into inert byproducts. You can't overdose on sunshine. You can absolutely overdose on capsules.

Holick paid for saying it out loud. In 2004 he was asked to resign his post in the Boston University dermatology department over a book arguing for sensible sun exposure. He kept his professorship in medicine and kept publishing.

No, and the trials say so. VITAL gave 25,871 adults 2,000 IU a day for five years and found no drop in cancer and no drop in cardiovascular events. The U.S. Preventive Services Task Force now recommends against vitamin D for preventing falls and fractures.

Sunlight itself keeps doing what the capsule can't. Swedish researchers followed 29,518 women for twenty years. The ones who avoided the sun lost between 0.6 and 2.1 years of life, mostly to heart disease, and the authors put sun avoidance in the same risk category as smoking.

The capsule copies one mechanism. Sunlight runs at least three.

Behind the rods and cones that give you vision sits a third kind of cell. David Berson's team at Brown found them in 2002. They carry a pigment called melanopsin, they contribute nothing to what you see, and they wire straight to the 20,000 neurons in your hypothalamus that run your master clock.

Here's the number that matters. Your living room runs 100 to 500 lux. The clock wants north of 1,000. Outdoor shade on a cloudy day gives you 10,000. That's not a percentage gap, it's a different category of thing, and a window doesn't fix it, because glass filters out the wavelengths you need.

Left in the dark, the human clock runs about 24.2 hours. Twelve extra minutes a day adds up to an hour and a half of drift in a week. When Sonia Ancoli-Israel's group put bright light in front of nursing home residents whose sleep had fallen apart, their rhythms tightened back up. Not a drug. Light.

Richard Weller, a dermatologist at the University of Edinburgh, found the second skin pathway. Your skin stockpiles nitric oxide, the gas that relaxes artery walls. UVA breaks it loose, it enters your bloodstream, and your arteries dilate.

He ran the lamps at constant temperature to rule out heat, and blocked the UVB to rule out vitamin D. Then he made the argument to rooms full of dermatologists whose entire public message was avoidance. Heart disease kills vastly more people every year than skin cancer. If moderate sun lowers cardiovascular death even slightly, the math on staying indoors stops working.

The same UVB that builds your vitamin D also is said to damage DNA, fusing adjacent bases where they should never bond. Your cells carry repair crews that clear thousands of those per cell per day. The system is good. It isn't perfect, and it slows down as you age.

Both things are true at once, and the dose decides which one wins.

Before antibiotics, tuberculosis patients were wheeled onto sun-facing balconies. Niels Finsen won a Nobel Prize in 1903 for treating skin tuberculosis with concentrated light, decades before anyone could explain why it worked.

I'm not telling you sunscreen is a scam – I believe in mineral based versions when you plan to stay out longer than normal. Skin cancer is real, burns are real, and past that window you should cover up. I'm telling you the human body seems to thrive when given adequate sun exposure each day.

-Jared

P.S. - My wife Baddie Crocker has a beautiful newsletter where she shares her perspectives on tending the land, recipes, women’s health and more.

P.S. - This newsletter does not provide medical advice. The content, such as graphics, images, text, and all other materials, are provided for reference and educational purposes only. The content is not meant to be complete or exhaustive or to be applicable to any specific individual's medical condition.

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