Why This Dermatologist Wants You to Get Some Sun

The sun is a natural source of energy, health and vitality. The more we learn about it the more we see that light from the sun is good for us. Every cell and organ of your body responds to light either through direct or through indirect pathways, ie from light landing on your skin and your eyes. It is essential for life, but it can also be destructive and even deadly. The question then becomes how to get the sunlight you need for optimal health without accelerating the aging process of your skin and without causing skin cancer.

What is Light: 

Light from the sun is electromagnetic energy (you can simply think of it as energy), not ionizing energy (like x-rays). It travels through the environment, and through your body every time your skin and eyes are exposed to sunlight, even through clouds, and it causes reactions in most cells of your body, directly or indirectly.

It has a broad range of wavelengths which we experience as: Infrared, Red, Orange, Green, Blue, Violet, Ultraviolet and more. You can think of it as a powerful communicator of what’s going on in the environment around you and translated as a set of instructions to your brain and other organs in your body, with powerful and long-lasting results. Sunlight can be translated into electrical and hormone signals in our brain and body. It can change the genes that the cells of your body express- this is called epigenetics.

The Sun:

• Sets your circadian rhythm. Exposure to UVB light helps regulate an important hormone called melatonin, made by your brain and your gut, to help you get a good night’s sleep and to stay asleep once you fall asleep. Melatonin levels go down with age so we need to find ways to optimize it.
• Affects your mood. Longer days and more light make us feel better. We could all use that right about now!
• Helps with vitamin D production, but it's not the only source of vitamin D. You can also get this vital nutrient from foods and from supplements.
• Helps with pain- when you get sunlight on your skin you may notice improved outcomes in pain levels from conditions like arthritis and other painful conditions. 
• UV light, and infrared light can also affect your hormone levels of estrogen and testosterone
• Can even offset dementia

Effects of Light on Your Mood, Health, Sex:

Getting the right amount of sunlight for the time of year helps regulate and modulate melatonin levels

• Melatonin is important because it positively impacts bone mass- increases bone production, reduces gonad (testes and ovaries) mass. 
• Melatonin is associated with darkness. Your melatonin levels are naturally increased in the winter and decreased in the summer since the shorter winter days means more darkness. During the long summer days, there is less melatonin because light arriving on the eyes activates photosensitive cells there which then shuts down production of melatonin.  
• It helps you fall asleep and stay asleep. It also activates the immune system and has anticancer properties. 
• Be very careful about taking it as a supplement and especially careful about giving it to children because it can affect the onset of puberty. 
• One note of caution: It’s the rise and fall and changes in duration of melatonin production throughout the season that gives it it’s health benefits, not taking it as a supplement. It is something your body does better at regulating naturally than with added supplements, in most cases.
• Light powerfully inhibits melatonin (even a bright light in the bathroom can do this so try to keep the room as dark as possible at night and low light in the bathroom at night if you need to get up to pee). 
• Get outside during the long days of summer. 

UVB and sex drive:

• Exposure to UV Blue light on the skin can trigger increases in testosterone and estrogen and the desire to mate. 
• Also, more light🡪less melatonin🡪more hormone output (more mating). Melatonin inhibits testosterone and estrogen from testes and ovaries. 

The eye-skin connection: 

As little as 1-3 minutes of exposure to red light from the sun early in the day a few times per week can reduce a lot of the vision loss experienced by those who are 40+ years old. There are cells in the back of the eye, called rods and cones, that absorb and convert light, mostly early-in-the-day red light into signals that are sent to the brain and the brain turns those signals into visual images which is how we see what we see. They get less efficient at making energy they need over time but exposure to red light helps restore that ability, and your vision along with it. 

Pain management: Just a few minutes a day of UVB light on the eyes and the skin can offset pain and reduce the amount of pain sensed by your body. UVB exposure to the eyes releases endogenous opioids which act as pain killers and increase your tolerance for pain.

UVB light and immune function: Why you get fewer colds/flu in the summer: 

There aren’t fewer infections floating around in the warm summer months, we’re just better at combatting them because increased exposure to UVB on the longer summer days indirectly affects the spleen, and our immune function. Here’s how:

• UVB light on the eyes, triggers activation of the sympathetic (autonomic) nervous system in the brain and turns on your immune system. 
• This in turn activates a channel and set of connections that lead to the spleen, and instruct it to deploy specific immune cells that scavenge for and combat infection. 

The Skin: 

• Contains melanin which absorbs UV light, creates pigment that protects your skin from excess sun exposure and damage. How well you make pigment is based on your genetics.
• The skin is an endocrine organ- hormone producing and influencing organ. When exposed to UVB light if you get enough exposure, there are increases of sex steroids- testosterone and estrogen (in proper ratio for males and females) and increased mate seeking. Enhanced female attractiveness. It also increased the desire to mate in both sexes. It also increased follicle growth and maturation- more healthy eggs produced. 20-30 minutes of midday sun exposure. Short sleeves, no hat no sunglasses. 2-3 times per week. Not sunbathing.  Increased sexual passion and desire to mate.
• Sunlight exposure to skin, UVB light upregulates P53 in skin cells (keratinocytes) which affects testosterone and estrogen production. 
• Even one exposure to UV changed output of corticotropins and beta endorphins which helps counter pain. Increases release of beta endorphins, which decreased pain sensitivity. Goes through clouds.
• Wound healing is faster in summer
• Hair grows faster after UVB exposure to the eyes- increases turnover of stem cells in skin, hair and nails. (proceeding  of National Acad of Sciences)

When to Avoid UV Exposure:

For every benefit I listed, there are risks of too much exposure and the results can be deadly. It's important to know your skin type and your family history of skin cancer and skin aging. Some can burn after just a few minutes while others can tolerate more exposure. Chronic sun exposure leads to P53 mutations that lead to skin cancer. You don't need daily exposure to get the benefits listed above. Two to three times per week of small amounts of exposure is all it takes. Chances are you are getting more than enough exposure just through regular incidental exposure while going for walks or running errands. Tanning is never a good idea and tanning salons are a very bad idea. They contain more UVA than UVB rays, which are not the ideal rays for the benefits lists, and, they accelerate skin aging even more than does exposure to natural sunlight.

An easy way to know when the rays are most dangerous are to check out the UV index, which is a measure of the intensity of ultra violet radiation. The higher the UV index, the less time it takes for damage to occur

The risks of too much sun include:

- Risk of skin cancer and premature aging of the skin

- Depends on skin type: Those who burn more easily need much less exposure and should seek out other ways to get the benefits listed

- Skin cancer: Those with a personal or family history of skin cancer need to be especially careful to protect their skin. You can't change your genetics but you can protect yourself by being sun smart (see below)

- Accelerated skin aging 

- Less efficient Vitamin D production. Too much sun can damage the skin which can make it less efficient at producing Vitamin D

- Wrinkles, blotchy skin, uneven skin tone

Bottom Line:

There is strong data that shows unequivocally how UV rays are good for you and vital for health. There is also strong evidence showing that too much, along with exposure to pollution and other lifestyle choices accelerate skin aging and skin cancer. The question is, how much is the right amount. The answer is, it varies by genetics, personal and family history of skin cancer and how easily your skin burns when you're outdoors.

There is even a clock, called the Horvath clock that measures how each of our organ’s age. As you might expect, the skin ages the fastest, almost entirely due to exposure to excess sun rays. It’s not a contradiction to say that spending time outdoors and in the sun is good- you can do both enjoy your time in the sun and protect your skin so you can age beautifully and keep your skin healthy.

Being sun smart:

👒wear a hat with a broad rim
👚wear sun protective clothing
🕶 wear sun glasses
🧴apply SPF 30 or higher and reapply every 2 hours or more often as needed
🧴apply sunscreen every day, all year round
🌥 try to avoid midday sun and seek shade when possible
☂️ consider carrying a sunbrella when shade is not available
👩🏻‍⚕️ look at your skin regularly and see a board-certified dermatologist for a full body skin exam every year or right away if you see anything new or changing

Reference: Huberman Lab Podcast #68 I encourage you to listen to it. I don’t agree with all his conclusions, but I always learn from him and appreciate his vast knowledge and research.