How much sunlight is healthy?

As a kid growing up in Hermosa Beach, California, I really loved summer. I’d spend every waking hour at the beach with friends, surfing or just kicking it on the warm sand. We worshipped summer. When the sun was shining, we were happy.

Woman Meditating

It wasn’t until I entered the solar energy industry that my thought and perception of the sun changed. The sun was good for more than just a nice day at the beach. It is a source of endless energy, and not just for solar panels.

Aside from the obvious benefits of solar energy, and aside from our obvious knowledge that the sun is the source of all food and life on earth, could I live without spending time at the beach? Could I survive without any exposure to the sun at all? Can humans survive without any exposure to sunlight?

We know that all plants require a certain amount of sunlight to make food and survive.  We know that animals get their energy from the food they eat and that food source gets its energy from the sun. Even animals that live deep underwater, where no sunlight exists, feed on organic matter (dead plants and organisms that sink to the ocean floor from the surface). This organic matter contains energy that was first produced by the sun.

Humans, like animals, also get our energy from the food we eat, and all of that food is derived from the energy of the sun. So, we need the sun to produce our food to survive. But do our bodies need direct exposure to sunlight to survive?

A study published in the American Journal of Medical Sciences, stated that humans need vitamin D to survive, and humans get their vitamin D from the sun. The study shows that those with the lowest vitamin D levels have more than double the risk of dying from heart disease and other causes over an eight-year period compared with those with the highest levels of vitamin D.

Sunshine vitamin D, as I like to call it, as opposed to a vitamin D supplement, also protects us against a host of other diseases, including heart disease, cancers, osteoporosis, prostate cancer and colon cancer. Sunlight vitamin D also has other health benefits, like protecting against depression, insomnia, and an overactive immune system.

Vitamin supplements alone cannot deliver the same healthful vitamin D as exposure to sunlight. The International Space Station uses LED lighting system with blue, white and red color spectrums, simulating the natural light we get on Earth in the mornings, afternoons, and evenings, to deliver similar health benefits as exposure to real sunlight. Recent studies have shown that LED lighting can cause the natural production of vitamin D3 in humans and has direct health benefits. You’ve heard of grow lights? Same thing.

A lamp with a just a bright white light will put you at risk of UV exposure, which can cause skin damage. Blue spectrum LED produces vitamin D3 and does without producing harmful UV radiation. Blue LED light, combined with white and red spectrum LED light, helps regulate our circadian rhythms and reduce depression and insomnia. But even this LED lighting cannot match all of the health benefits of sunlight. And it certainly can’t heat the sand under your feet.

Humans need natural sunlight. But there is no simple formula to determine how much natural sunlight is enough for the human body to produce enough vitamin D, and at what point exposure to the sun becomes unhealthy. Here’s why. The intensity of the sun varies by location on earth as well as the time of year. A person’s skin type will also play a big role in calculating what is a healthy sun exposure for them.

For the the sake of conversation, let’s try coming up with a formula for a middle-aged adult male with fair skin, who lives in California (no, it’s not me). According to the USDA recommended dosage, this person needs about 600 international units of vitamin D per day. Based on that goal, 10 minutes of mid-day sun in June at 1,000 ft. elevation while wading in the pool, will supply this person with the recommended daily allowance to maintain proper vitamin D health. That is, of course, if this guy already has a proper balance of vitamin D in his body, and that the proper exposure to sunlight is repeated each day.

An article published in Scientific America determined that almost 75% of all teens and adults in the U.S. suffer from vitamin deficiency.