Healthy Living: Sunlight and Your Health

It's Not All Bad

When you think of the sun, your first thought might be about the damage it can do.

When you think of the sun, your first thought might be about the damage it can do. And too much can cause several kinds of serious health issues. But small amounts, especially early in the day before it's at its brightest, can be good for you in some ways.

How Much Is Enough?

In general, scientists think 5 to 15 minutes -- up to 30 if you’re dark-skinned -- is about right to get the most out of it without causing any health problems.

This answer is different for everyone. It depends on your skin tone, age, health history, diet, and where you live. In general, scientists think 5 to 15 minutes -- up to 30 if you're dark-skinned -- is about right to get the most out of it without causing any health problems. You can stay out longer and get the same effect if you use sunscreen. Talk to your doctor about what's right for you.

Vitamin D

The sun’s UV rays help your body make this nutrient, which is important for your bones, blood cells, and immune system.

The sun's UV rays help your body make this nutrient, which is important for your bones, blood cells, and immune system. It also helps you take in and use certain minerals, like calcium and phosphorus. And while most people get enough vitamin D from food, children who don't can get rickets, which softens and weakens their bones.

Protection Against Certain Conditions

Too much time outside can raise your chances of skin cancer.

Too much time outside can raise your chances of skin cancer, but people who live in places that don't get much sunlight may be more likely to have other types of the disease, including breast, colon, prostate, and lung. Their odds of getting other serious conditions, like multiple sclerosis, high blood pressure, diabetes, and heart disease, may be higher, too. Scientists think this might be linked to lower levels of vitamin D.

Better Sleep

Your eyes need light to help set your body’s internal clock.

Your eyes need light to help set your body's internal clock. Early morning sunlight in particular seems to help people get to sleep at night. This may be more important as you age because your eyes are less able to take in light, and you're more likely to have problems going to sleep.

Weight Loss

Morning light also seems to help people keep the fat off.

Morning light also seems to help people keep the fat off. You need 20 to 30 minutes between 8 a.m. and noon to make a difference, but the earlier you get it, the better it seems to work. Scientists think the sun's rays may shrink fat cells below your skin's surface. More sunshine means you're probably getting more exercise too, which is good for you in lots of ways, including shedding pounds.

Emotional Well-Being

Sunlight helps boost a chemical in your brain called serotonin, and that can give you more energy and help keep you calm, positive, and focused.

Sunlight helps boost a chemical in your brain called serotonin, and that can give you more energy and help keep you calm, positive, and focused. Doctors sometimes treat seasonal affective disorder (SAD) and other types of depression linked to low levels of serotonin with natural or artificial light.

Eye Health

Too much direct sunlight can hurt your eyes.

Moderate amounts of sun over your lifetime, especially in your teen and young adult years, might make you less likely to have problems seeing things at a distance (nearsightedness). But too much direct sunlight can hurt your eyes. It can lead to blurred vision and raise your chances of cataracts.

Your Skin

Regular, small amounts of ultraviolet light may help ease the symptoms of certain skin conditions like eczema, psoriasis, and vitiligo.

Researchers think the three primary types of skin cancer -- melanoma, basal cell carcinoma, and squamous cell carcinoma -- are mostly caused by too much time in the sun. So it's very important to use sunscreen or cover up if you're going to be outside longer than 15 minutes or so. But regular, small amounts of ultraviolet light may help ease the symptoms of certain skin conditions like eczema, psoriasis, and vitiligo.

Sunlight as Treatment

In addition to some skin issues, filtered sunlight also can be used to treat a condition called jaundice that mostly affects newborns.

In addition to some skin issues, filtered sunlight also can be used to treat a condition called jaundice that mostly affects newborns. It happens when there's too much of the chemical bilirubin in the blood, and it makes a baby's skin look slightly yellow. Putting the baby in sunlight behind a window (to filter out the harmful kinds of rays) may help get rid of the bilirubin. Never put a newborn in direct sunlight outside.

Don't: Get Too Much Sun

Sunburned skin uses white blood cells from your immune system to heal

Too much time outside without protection can not only make you more likely to get skin cancer, it can make your skin age faster, too, causing wrinkles, a leathery texture, and dark spots. And sunburned skin uses white blood cells from your immune system to heal. That can affect your body's ability to fight off germs and make you more likely to get sick.

Do: Protect Your Eyes

You need sunglasses that block UV light and broad-brimmed hats whenever you’re outside for a while.

You need sunglasses that block UV light and broad-brimmed hats whenever you're outside for a while. The sun can damage your eyes any time, not just in summer, and the rays can pass right through clouds. (Don't forget that kids need this same protection, too.)

Do: Use Sunscreen

An SPF of 15 or higher is best. Look for “broad exposure,” which blocks more of the UV light.

An SPF of 15 or higher is best. Look for “broad exposure,” which blocks more of the UV light. Put it on 30 minutes before you go outside, and don't forget areas like your lips, ears, and neck. Put more on if you swim or sweat. Try to stay out of the direct sun between 10 a.m. and 4 p.m., when the sun's rays are strongest, and take breaks inside.

Don’t: Go to Tanning Beds

Tanning beds also raise your chances of skin cancer.

This also raises your chances of skin cancer. If you do it before age 35, you're 60% more likely to get melanoma, the most serious form. Even one session can raise your odds of melanoma by 20% and other types by as much as 65%. If you want that all-over body tan, tanning lotions might be an option. Most are safe, but they usually don't have sunscreen in them, so don't forget to put that on as well.

Do: Go to the Dermatologist

Check your skin once a month or so.

Check your skin once a month or so. If possible, ask a family member to help if you can't see everywhere on your body. Stand in front of a full-length mirror -- a chair and a hand mirror can help -- and look all over for any new growths or changes in old spots. See your doctor or dermatologist if you notice anything unusual.

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REFERENCES:

  • American Academy of Ophthalmology: “Natural Light May Benefit Seniors' Biorhythms, Sleep and Health,” “Exercise for Eyes and Vision,” “The Sun, UV Radiation and Your Eyes.”
  • American Academy of Pediatrics: “Jaundice in Newborns: Parent FAQs.”
  • Environmental Health Perspectives: “Benefits of Sunlight: A Bright Spot for Human Health.”
  • American Academy of Family Physicians: “Effects of Sun Exposure.”
  • Harvard Health Publications: “Benefits of moderate sun exposure,” “A prescription for better health: go alfresco.”
  • JAMA Ophthalmology: “Association Between Myopia, Ultraviolet B Radiation Exposure, Serum Vitamin D Concentrations, and Genetic Polymorphisms in Vitamin D Metabolic Pathways in a Multicountry European Study.”
  • Journal of Psychiatry and Neuroscience: “How to increase serotonin in the human brain without drugs.”
  • Mayo Clinic: “Sunless tanning: What you need to know,” “Rickets.”
  • Medscape: “Filtered Sunlight Effective Against Jaundice in Neonates.”
  • Northwestern University: “Morning Rays Keep Off the Pounds.”
  • Pediatric Allergy and Immunology: “The influence of sun exposure in childhood and adolescence on atopic disease at adolescence.”
  • PLOS ONE: “Timing and Intensity of Light Correlate with Body Weight in Adults.”
  • Skin Cancer Foundation: “Step by Step Self-Examination,” “Early Detection and Self Exams.”
  • Stanford Medicine: “Filtered sunlight a safe, low-tech treatment for newborn jaundice.”
  • StudyFinds.org: “Lack Of Sunlight Exposure Behind Winter Weight Gain, Study Finds.”
  • World Health Organization: “The known health effects of UV.”
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