Does Avoiding the Sun Shorten Your Lifespan? | Chris Kresser
The ADAPT Practitioner Training Program enrollment is now open. Learn More

Does Avoiding the Sun Shorten Your Lifespan?

by

Published on

avoiding the sun, avoid sun exposure
Avoiding the sun is many times just as bad as getting too much sun. Photick/Odilon Dimier/Thinkstock

A few weeks ago I was at a conference in Tucson, Arizona. Two things really surprised me while I was there. First, quite a few people ordered egg-white omelets for breakfast. Huh? Didn’t they get the memo that dietary cholesterol doesn’t increase the risk of heart disease, or even raise blood cholesterol levels? Egg-white omelets are so 1995!

Second, I noticed that a number of people were slathering themselves with sunscreen and wearing long sleeve and pants or wide-brimmed hats every time they stepped out the door in order to avoid the sun.

This kind of “sun phobia” is the unfortunate—but inevitable—result of national guidelines in many countries over the past 30–40 years advising strict restriction of sun exposure.

Too much sun exposure isn’t a good thing, but not enough may be even worse. Read this to find out why.

These guidelines were based on the observation that light-skinned people of European ancestry living in Northern Australia had the highest risk of malignant melanoma, the deadly form of skin cancer, in the world. However, as you’ll see below, applying guidelines that were originally developed for people living in an area with a high ultraviolet (UV) index, such as Northern Australia, to areas with limited sunshine and a much lower UV index (such as many parts of North America and Europe) is not only unnecessary, it may be harmful.

Not Enough Sun Exposure May Be Just as Harmful as Too Much

In a new study, researchers tracked the sun exposure habits of 30,000 Swedish women for 20 years. They found that the women who strictly avoided the sun during that period had a two-fold greater risk of early death than women who received normal amounts of sun exposure.

What’s more, they found that women with normal sun exposure habits were not at significantly increased risk for malignant melanoma or melanoma-related death. (1) This is consistent with the results of a previous Swedish study that followed 38,000 women for 15 years and found that sun exposure was associated with reduced risk of both cardiovascular and overall death. (2)

I’d like to emphasize that these studies are observational in nature, and thus do not prove causality. It’s possible that the women who got more sun had healthier diets and lifestyles than those who avoided the sun, and those factors led to the lower mortality, rather than the sun exposure.

However, it’s also possible—and probable, in my opinion—that completely avoiding does increase the risk of death. There are several possible mechanisms that explain why:

Vitamin D

One of the primary benefits of sunlight is its ability to stimulate vitamin D production. Vitamin D deficiency is a major predisposing factor in at least 17 varieties of cancer, as well as heart disease, stroke, hypertension, autoimmune disease, type 2 diabetes, depression, birth defects, infectious disease and more. (3) It’s not a stretch, therefore, to imagine that women who avoid the sun have lower vitamin D levels (especially in areas with limited sun, like Sweden) and thus a higher risk of death.

Blood Pressure

Scientists observed a connection between sunlight and cardiovascular disease as far back as the 1970s, when clinical trials on hypertension showed that blood pressure was consistently lower in summer than winter. (4) Later studies showed that the both the prevalence of hypertension and average blood pressure is directly correlated with latitude; in other words, those living at northern and southern latitudes (with less sunlight) had more hypertension and higher average blood pressure, while those living closer to the equator had less hypertension and lower average blood pressure. (5)

Clinical experiments have also provided direct evidence that ultraviolet light reduces blood pressure. In one study, researchers exposed one group of people to lamps that gave off ultraviolet light as well as heat, and another group to lamps that only gave off heat. In the group that received both heat and ultraviolet light, blood pressure dropped significantly after just one hour of exposure. (6)

How does sunlight lower blood pressure and reduce the risk of cardiovascular disease? Sunlight stimulates the production of a chemical called nitric oxide in our skin. Nitric oxide helps our blood vessels to relax and expand, which in turn reduces blood pressure. This is important because high blood pressure is one of the strongest risk factors for cardiovascular disease, and even relatively small reductions in blood pressure can dramatically reduce the deaths from both heart attack and stroke.

For example, a drop of 20 mmHg in systolic blood pressure (blood pressure is expressed as a fraction, i.e. 120/80, and “systolic” refers to the number on the top) leads to a two-fold reduction in the overall risk of death in both men and women between the ages of 40 and 69. (7)

Inflammation

Sunlight may also reduce the risk of cardiovascular disease—and by extension, the risk of death—by putting the brakes on inflammation. (8) These beneficial effects of sunlight are likely to extend to other organs and tissues as well, since both blood pressure and inflammation have widespread effects in the body.

Immune Function

Another effect of sunlight that isn’t mediated by vitamin D is its ability to regulate immune function. Studies have shown that the the more hours of sun there are where you were born, the lower the risk you’ll develop multiple sclerosis. (9)

Along the same lines, the more exposure to sun people have where they work and live as adults, the lower their rates of MS, and relapse rates for MS are higher in winter than in summer. (10) Evidence for benefit from sunlight is strong for other autoimmune diseases as well, such as type 1 diabetes.

Other Effects

Exposure to sunlight may improve endocrine function, elevate mood (via its effects on certain brain chemicals like serotonin) and increase DNA repair capacity, all of which could conceivably extend lifespan. (11)

The “Goldilocks” Effect: How Much Sun Exposure Is “Just Right”?

With all of this in mind, how much sun exposure is “just right”? How can we minimize our risk of skin cancer while optimizing vitamin D levels and getting the additional cardiovascular and immune benefits of sunlight?

Just follow these guidelines for you and your family members:

  • If you have fair skin, aim for spending about half the amount of time in the sun that it takes for your skin to turn pink (without sunscreen) two to three days a week. This could be as little as 10 minutes for those with very fair skin. If you have dark skin, you may need up to two hours per day to generate the same amount of vitamin D (which is why supplementation may be necessary for those with darker skin).
  • Never burn yourself in the sun. Cover yourself with light clothing, wear a hat, shade yourself with an umbrella, tree or canopy, wear sunglasses, and/or use a safe sunscreen to prevent sunburn if you’re going to be exposed to sunlight for a prolonged period. (But see the section below for important information about sunscreen.)
  • Pay attention to the time of day, latitude and season. This probably goes without saying, but you need less sun exposure at mid-day during the summer on the equator to generate a given amount of vitamin D than in the late afternoon during the winter in New York City. Vary your exposure accordingly.
  • Infants under 6 months old don’t have much of the protective pigment (melanin) in their skin. It’s best to avoid direct sun exposure at mid-day, use protective clothing and a hat, and limit exposure to the morning or late afternoon hours. Infants may be particularly susceptible to the toxic effects of some sunscreen ingredients, so use clothing or shade when possible.

Sun protection is important if you plan to be out in the sun for a long enough time to get burned, but most sunscreens on the market are not beneficial or even safe. Stephan Guyenet explains on his blog how typical sunscreen fails to prevent melanoma, the deadliest form of skin cancer. Most commercial sunscreens have a slew of chemical ingredients such as fragrances, parabens, alcohols, chemical solvents and petroleum oils that break down when exposed to sunlight.

Unfortunately, even natural sunscreen materials like zinc oxide could be problematic. (12)

Researchers have recently discovered that, in vitro, zinc oxide may generate free radicals when exposed to UV radiation, which could damage cells and raise the risk of cancer. (13) More testing needs to be done, but this preliminary research shows that even natural sunscreen ingredients could have unforeseen consequences to your skin health. Until we know more, however, using a natural, mineral based sunscreen is still a better choice than the chemical sunscreens that are commonly available.

Ultimately, the best way to protect yourself from melanoma—while ensuring you still get the benefits of sun exposure—is to tan gradually, without burning.

Final Thoughts

It’s entirely possible that public health recommendations that significantly restrict sun exposure may be doing more harm than good in regions with limited sunshine and a low UV index, such as many parts of Europe, the UK, and North America. Yet many people are unaware that the advice they’ve been given about avoiding sun exposure doesn’t reflect the current scientific evidence on this topic.

This reminds me of the situation we’re in with dietary fat and cholesterol. The mainstream media and medical establishment spent decades scaring us away from egg yolks, cheese, meat, and other high-fat, high-cholesterol foods. The result of this advice was an increase in the consumption of highly refined carbohydrates—which, ironically, contributes to the epidemics of metabolic and cardiovascular disease that fat and cholesterol restriction was supposed to address.

As I mentioned in a recent podcast, the current evidence suggests that (on average) dietary cholesterol and saturated fat do not affect blood cholesterol levels or increase the risk of heart disease. Yet I think it’s safe to say that most people still perceive a breakfast of cold cereal, toast, and OJ to be “healthier” than bacon and eggs. It took years to convince people that natural fats found in real foods are bad for them, and unfortunately it’s probably going to take years to relieve them of the burden of that misunderstanding.

I’m afraid the same will be true for sun exposure. I often see parents putting sunscreen on their kids as soon as they step out the door, or adults that wear long sleeves and big hats whenever they go outside. Current research doesn’t support this, but I think it’s going to take a while for the public policy to change and the message to get out. (Though you can help speed that along by sharing this article with people you know that are still sun-phobic.)

158 Comments

Join the conversation

  1. It should be noted that as people get older, their ability to create vitamin D3 thru sun decreases. There may be underlying health reasons for this so may not apply to all people. Even though I get sun, I notice I need to still take more D3 when taking vitamin K2.

  2. I’m a lifeguard. I’m in the sun for 7-8 hours a day and I never burn. I have horrible tan lines and I am so white in some places and so dark in others.

    • One possibility on why you don’t burn as much is that you may have a lot of anti-oxidant in you. There us something called Grounding. It is suppose to deliver a good dose of radiation. This would apply at a beach. You will be in touch with the earth. This is only a possible theory.

      Some areas of the body will get higher concentration of sun.

  3. I would also like to make a new comment about beta carotene. In summer I eat alot of raw fruit and throw in some carrots…and I get a yellow colour from too much beta carotene, which I understand the body is storing the excess. When I spend moderate time in the sun I discovered I developed an easy nice base tan and dont burn. The yellow tinge disappears. I also quench my skin with aloe vera. Worth a try if you are a burn no matter how long you spend outside person!

  4. I should mention also that we use sunscreen when at the beach in direct sun for prolonged periods and in the water. Just not every time we are out and about. I think the message came about because you see everyone lying in the sun baking for hours to get a tan! The Australian sun is harsh, no doubt but its often too hot to be outside at peak times anyway so air con runs and we all stay indoors more.

  5. Hi Chris
    I grew up in New Zealand and NEVER wore sun screen. I believe a natural base tan and stored beta carotene under the skin is protection. As a teen I burned alot…oops! Im very fair. I now live in Australia, for the past 19 years, and get the sunscreen message bombarded here! I use sunscreen on my face now but not every day. My children have a light olive complexion and tan without burning. I adhere to the hours of the day rule and let them out to play before 11am or after 4pm. Everyone I know lathers sunscreen on their kids so they look sticky and white and stinging eyes. I cover up sensitive areas with clothing and once we get hot we come out of the sun. Everyone i know has vit D deficiency and pop pills. Where is the balance and common sense today?

    • I agree with your post except that I think you are keeping your kids inside during peak UVB hours, which would limit D3 production in the skin. Might want to consider that.

  6. hello, please i have something interesting,

    i am hypothyroid i.e. hashi….and i tested my D lvl -25 one, and it was slightly below minimum range , so i started supplementing with 3000 i.j vitamind d3, and after 6 days i sensed my mole on the face started beeing sensitive like burning sensation….i ignored then after 10 days of supplementing a mole on my back started beeing so painful that i immediately stopped taking vitamin d3 …..and it got better 5 days after….

    did you ever hear about moles sensitivity when supplementing d3? is that a connection between moles, sun and melanoma??

    thank you

    • One needs to understand that vitamin D3 doesn’t work alone. D3 needs K2, calcium and A. Most people are usually missing the K2.

      Here is one brand formulation

      Vitamin D3 (as Cholecalciferol) 2,000 IU 500%
      Vitamin A (as Retinyl Palmitate) 3,000 IU 60%
      Vitamin K2 (as Menaquinone-7) 100 mcg 125%
      Tocotrienols (as DeltaGOLD® Tocotrienols) 5 mg

  7. I have been lucky enough to be in the sun a lot this summer, and I wear sunscreen all the time, but I still get tons of sun. I’ve even gotten sunburned because I didn’t apply it enough. A friend of mine, who is hispanic, got extremely burned under an umbrella with a hat on who put no sunscreen on. How does putting sunscreen on hurt you? You still get sun–just not as much. So unless you are only going to be in the sun for an hour, I don’t see why you wouldn’t want to put it on.

  8. That all reminds me of this:
    If you allow yourself to get uses to something, step by step,
    then you may be able to get more immune.

  9. Any thoughts on Red Light beds? (as opposed to tanning beds) The local firm makes claims about stimulating nitric oxide, among other things. It centers at 633 nm.

    • I am a bed ridden patient who is not exposed to sun since 2 years. Suddenly i got exposed to sun for about 2 minutes directly in the evening. I got a small brown patch under my eye. My skin tone is creamy white. How much time I should get exposed without getting these patches.

      Please help.

  10. Wow, great conversation!

    I’ve had trouble for years with assimilating oils. Using enzymes and eating close to all-raw for about 2 years didn’t help with that. Besides feeling many weird sensations (some of them good) during that time, when I went out on the roof deck, I felt that the sun shining down on me was not good! Which was significant, since I partly grew up on the beach in San Diego and got lots of sun, without sunscreen or sunglasses.

    So when I realized I couldn’t handle all-raw, and started eating red meat, etc. (which I have always loved), sunshine began feeling good again. Years later, still having trouble assimilating oils, and not able to tolerate D3 on a regular basis, I learned about K2. And now I’m really enjoying sunshine again.

    I’ve been told that white spots on the skin are par for the course as we grow older. I assume that mine are from sun damage when I used to bake on the San Diego beach. Have had no skin cancers, though.

    I’m wondering if any of you older people (I’m in my mid-60’s) have had white skin spots go away. I long for the look of the evenly sun-tanned skin that I had growing up.

  11. For the past year or so I’ve been doing the Weston Price “diet” and/or taking suppliments (Mk7-vitk2), resveratrol, eating as much fermented foods as possible, gelatin (not often enough) and when I go out in the sun, I’m using Maui Babe that has vitamin E in it among other vitamins and coffee! But it has no sunblock. I live in Ohio and all my life never tanned, only burned. And like some of you had sun rashes (especially when I went vegetarian). Well. I was in the sun all day yesterday and didn’t burn one bit. I’m actually surprised!

  12. Great article Chris. This roughly sums up my own attitude towards sun exposure.

    Do you have any comment on how the ratio of UVA to UVB light can affect your health, either positively or negatively?

    To give you an example the UVA to UVB ratio obviously changes throughout the day, year and lattitudes, with midday summer sun for a location having a higher ratio of UVB. However I have read that UVA tends to stay more constant due to its ability to penetrate barriers such as the ozone layer more effectively than UVB. I have also read that there is only enough UVB for adequate Vit D production when the sun is over a certain angle (over 50° if I remember correctly) which usually only happens around solar noon during summer in locations further away from the equator. In winter the sun may never reach over 50°. Does then, this extra UVA radiation cause any negative effects?

    • Sorry Chris is wrong with his advice for being in the sun early morning or late afternoon! The opposite is true!
      Phili is quite correct about the angle of the sun. Quite simply a good rule of thumb at any location and any time of the year is to stand outside and look at your shadow. If your shadow is shorter than your height that is a good time to be in the sun as UVB rays will be prevalent. The longer your shadow the less UVB rays and the more UVA rays which are the ones responsible for melanoma.
      Another useful piece of info is when you have had a good dose of sun exposure and take a shower or bath do not wash with soap or detergent for 24 hours as Vit D3 is formed from the action of UVB rays on the cholesterol in your skin. As the cholesterol is a lipid it is fat soluble and you will simply wash away all the benefit of healthy sun exposure.
      Obviously it is OK to use soap underarms and the groin area!
      A final piece of surprising info is to limit time spent under glass as UVB rays are filtered by it and harmful UVA rays penetrate.
      Further info and research results can be found at D Action .org which is an organisation set up specifically to research Vit D and it’s effects.
      Hope this is useful!
      Denis

  13. Based on the research I have done Chris has missed the very important fact that UVB is the one that produces vitamin D and it gets through to the surface ( duration depending on where you live) only during the middle hours of the day, and any many places only from mid Spring to mid Autumn.

  14. I also have heard that midday sun is the best for us because it is a higher proportion of UVB to UVA rays. Late afternoon sun is proportionately more UVA. Is this true?

  15. Is the reduction in autoimmune diseases because of higher vitamin D levels from the sun, or is it from some other effect? Does taking vitamin D supplements have an equally beneficial effect?

  16. Australia has really high rates of melanoma. Australia is a high sun country, beaches, exposure etc. There is no doubt that overexposure in the Australian sun will guarantee melanomas eventually. Seems to me that you avoid melanomas by staying out of the sun but by doing that you don’t get the vitamin D you need.

    There is no easy path with this.

    • Yes, I think the problem is that the recommendations to decrease sun exposure occurred in parts of the world that don’t really need to be as careful as more equatorial regions. It makes sense for light skinned people living in places like Australia to limit sun exposure. It makes less sense if you live in Canada. I have a relative who lived only in norther Europe and Canada, with no history of burns, and still ended up with melanoma. Sun exposure just isn’t the only factor at play.

      People from norther latitudes got around the ‘Vitamin D winter’ by ingesting foods high in Vitamin D, so I think that supplementation is an option for people who need to avoid intense Australian sunlight. But apparently 10 minutes of sun exposure is enough to produce good Vitamin D levels, so some Australian sunlight in the mornings could still be an option.

  17. I was once totally caught up in the low fat craze. During that time I could not get in the sun without a horrible reaction of hive like ruptures (some called it sun poisoning). Fast forward a few years when I switched to a high good fat diet and the sun was no longer a problem. I stay out till I see any pinkness then head for a spot of shade. Also noticed if I put coconut oil on my skin after showering and totally let it sink in, that day I seem to be able to be in the sun longer without getting pink. By the way I turn 70 this year and frequently get compliments on my skin.

  18. There has been strong evidence for many years now that the consumption of industrial seed oils, which are high in omega 6 PUFAs, is linked to cancer.

  19. I have loved the sun as long as I can remember. However, I have lived in Minnesota all (almost) 40 years. I live for summer. But sadly, days spent outside are few for me, as well as many others who don’t enjoy our frigid winter.
    Through my twenties, I was in the sun less than in my teens, due tommy busy life. Luckily the last 6 have been filled with summer fun, due to my wonderful man & his boat. We live near wonderful lake Minnetonka & spend as much time there as we can! The first few summers I would break out into a rash early in the season. Was it the sunscreen? Or was it a sun allergy? As the years go on, I am less & less sensitive. And I get tanner if that’s possible, with less effort. Is it my new found paleo diet (journey has been 4 years to full paleo)? Or am I just becoming “immune” to sunburn? I still use some sunscreen on my face & chest especially if we are spending long hours or multiple days.
    Anyway, I will take my chances. It makes me feel alive! Happy summer, everyone!
    -shanntini