Why Sunlight is Good for You!


Positive benefits of being out in the Sun

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Few seem to realize that the Sun in April is as strong as it is in August, especially once we hit the middle of the month. Solar fear and confusion still abound. The marketing of ultrablocking sunscreens and special sun-protective clothing plays into these fears. I certainly got repeatedly surprised when I researched the Sun’s health effects.

Sunlight Lifts Your Mood

Everyone probably instinctively senses that sunlight enhances their mood and whittles away depression. This may be due to the fact that its rays cause the brain to release seratonin, which makes you feel good during the day. It also helps you feel more alert, more focused, and calmer. 

Research suggests that light hitting your skin, not just your eyes, helps reverse depression, especially those at risk of seasonal affective disorder (SAD). Moreover, being outside gets us golfing, gardening, and engaging in other types of physical activity.

Sunlight Improves Your Sleep

We all know the sunlight produces melatonin, often called the “sleep hormone.” Yep, this happens during darkness at night! The more sunlight your body enjoys, the more melatonin you produce at night. This improves your sleep, synchronizes your biological clocks, and lowers stress.  Getting into a natural sleep cycle is important to reduce depression.

Sunlight Produces Weight Loss

As mentioned above, sunlight influences sleep and circadian rhythm, both of which have been shown to influence weight regulation. So it may not surprise you that sunlight promotes weight loss. Research reveals that as little as 20 to 30 minutes of morning sunshine can reduce body fat and help you shed those extra pounds.

So, get outside for a morning walk!

Sunlight Improves Bone Health

We’ve long known that “the sunshine vitamin” (Vitamin D) promotes calcium absorption which is essential for bone growth and formation. And many of us have low levels of vitamin D which leads to poor bone health. 

The primary salutary mechanism is that sunlight’s medium-length ultraviolet rays, called UV-B, interact with cholesterol in the skin to create a type of beneficial vitamin D you will not get from popping vitamin pills.

Just 5 to 15 minutes of pure sunlight per day will give spark this hormone which promotes calcium. The Vitamin D needs activation. The Sun helps to convert inactive Vitamin D levels to active.

Sun Rays and Cancer

According to the Cleveland Clinic in Ohio, inadequate levels of Vitamin D have been associated with an increased rate of infection, cancer, and even mortality rate after surgery.

Yes, cancer. Most of us are aware that chronic exposure to ultraviolet (UV) radiation present in sunlight is responsible for the induction of most nonmelanoma skin cancers. Solar radiation is a well-established skin carcinogen, responsible for more cancers worldwide than any other single agent.

However, in the past two decades many have carried this too far. Did you know: Sunlight is also associated with reduced risk for many chronic illnesses including cancer and cancer mortality.

In people with sensible sun exposure, vitamin D reduces risk of malignancy and are less likely to contract ovarian cancer, pancreatic cancer, colon cancer, Hodgkin’s lymphoma and prostate cancer.

When prevention of some or many of these are balanced against the 8,000 annual new cases of melanoma, we can’t simply define sunlight as “friend” or “enemy.” 

 Nobody wants to get skin cancer, but we’ve gone from sun worship to sun dread.

How Much Sunlight?

Slopping SPF blockers onto our skin whenever we step outdoors is not a good idea until you’ve received at least 15 or 20 minutes of daily exposure. That’s the recommended amount. At minimum, with just face and arms exposed, try to get at least 15 or 20 minutes of strong sun a day, a few times a week. 

If you’re outside for an extended period of time, wear sunscreen with a sun protection factor (SPF) of at least 15 plus a hat and shirt around midday.

Also, consistency is important. If your skin hasn’t seen the sun in a long time, you are more susceptible to sun burn. Suddenly getting a lot of sun is more dangerous then steady exposure over time.  In fact, studies have shown that outdoor workers who were exposed to regular sunlight had a lower risk of developing skin cancer compared to their indoor counterparts. 


A word about the glass in car windows, offices, and homes

Glass that is transparent to visible light absorbs nearly all UVB. This is the wavelength range that can cause a sunburn, so it’s true you can not get a sunburn through glass. However, about 75 percent of UVA passes through ordinary glass. UVA leads to skin damage and genetic mutations that can lead to cancer. So, perhaps it’s better to open that window and let glassless sun rays hit you.

Sunlight and Health Benefits

Other studies show sunlight delivers benefits for various skin conditions, and also for helping prevent or relieve thyroid problems, rheumatoid arthritis, systemic lupus, and inflammatory bowel disease.

It doesn’t take long to gain such benefits. You needn’t sunbathe for hours and, indeed, should never let your skin burn. To appraise the vitamin D your body will create during this next month, consider that a glass of fortified milk contains between 50 to 100 IU’s of that vitamin. With that in mind, consider:

Sunbathing in a swimsuit for 30 minutes lets the average-sized body create:

  • 50,000 international units (IUs) of vitamin D in people with light skin tones.
  • 20,000 to 30,000 IUs in people who already have a tan
  • 8,000 to 10,000 IUs in people with dark skin tones

Does this mean that it’s safe for people with darker skin to spend more time in the sun? Yes and no. Certainly, people with pale skin types who sunburn easily and don’t tan are more likely to get sun-related skin cancer. However, dangerous skin cancers are more common among darker-skinned people. Also, while skin cancer is much more common overall among lighter-skinned people, it tends to be more deadly among people of color because diagnosis is often delayed. In conclusion: Everyone can get skin cancer.

The huge amount of vitamin D the body creates in such a short time implies that it’s a very desirable substance, since nature doesn’t seem to do anything for no reason.

It’s actually pretty amazing. Our own Sun gives us one of the healthiest vitamins of all, vitamin D, in just 15 to 20 minutes so that we can live and grow healthily.

Protect Children From Sunburn

The danger of sunburn matters most when you are young (before the age of 20). A large Scandinavian study of melanoma risk published in the Journal of the National Cancer Institute in 2003 found that adolescence is the most dangerous time to get a sunburn. Recent sun exposure doesn’t seem to be associated with basal cell carcinoma, the mildest form of skin cancer. Squamous cell carcinoma appears to be different. Cumulative and recent exposure to sunlight at any age is strongly associated with actinic keratoses, scaly growths on the skin that are a risk factor for that type of skin cancer.

Pets Benefit From Sunlight, Too

Dog and cat bodies use UV-B like humans do, but their skin plays no role in the process. Instead, oils in their fur is what converts it to the vitamin. When they clean or groom themselves, they invariably swallow some. It’s a major reason nature programed our pets to lick themselves so much! Studies show that pets with higher vitamin D blood levels have fewer cancers and better heart health.

Bottom line: We astronomers are mainly focused on the night sky, but—starting around now, in April—the best thing we get from the firmament bombards us long before sunset. Get outside and enjoy the sunlight!

About The Author

Bob Berman

Bob Berman, astronomer editor for The Old Farmer’s Almanac, covers everything under the Sun (and Moon)! Bob is the world’s most widely read astronomer and has written ten popular books. Read More from Bob Berman

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