The Mental Health Benefits of Sunlight

a woman wearing a straw hat and sunglasses sunbathing at the beach on a lounge chair

Nick Dolding / Getty Images 

While we all know the hazards of spending too much time in the sun—like skin cancer, sunburns, and premature aging—there are also many vital benefits of sun exposure. From bone and immune health to depression and seasonal affective disorder (SAD), sunlight offers powerful restorative, protective, and healing effects.

The skin cancer awareness campaigns of the past several decades have been so successful that many people don't realize all of the good things time in the sun can do for the mind and body—or the dangers of not getting enough sunlight.

Those warm, yellow rays help the body make vitamin D, an essential nutrient the body needs to function properly, and the body can't absorb or process calcium without it.

Vitamin D is essential for bone, heart, lung, dental, immune, nerve, and muscular health, as well as for optimal mental health. Deficiencies in vitamin D (and calcium) can cause serious conditions, such as the bone disease called rickets. Also, those with lower levels of vitamin D may be at higher risk of a range of diseases such as cancer, diabetes, high blood pressure, schizophrenia, and depression.

History

For most of human history, people spent much of their time outdoors, under the sun, getting more than enough sunlight, which the skin converts to vitamin D. Any excess was stored in body fat.

Many cultures worshipped the sun, praising it for bringing life and good health. Thus, sunbathing was used to promote health and "cure" many ailments, such as tuberculosis and skin conditions.

Scientific evidence confirms that sufficient sunlight is essential for optimal functioning of the mind and body.

Industrial Revolution

The Industrial Revolution brought many people indoors to work in factories and offices, and children were either in classrooms or at home all day. Industrialization also created pollution that blocked out the sunlight. This huge reduction in natural sun exposure caused serious deficits in vitamin D for generations of children until scientists discovered the link between vitamin D deficiency and a lack of sun exposure.

Rickets, which is a softening or weakening of the bones primarily found in children but can also impact adults, became epidemic until exposure to the sun's ultraviolet radiation (either via sunlight, sunlamps, or vitamin D intake) was reevaluated and reintroduced.

Rickets can be fully prevented and treated with adequate sun exposure and/or drinking and eating vitamin D fortified foods. Many people don't think twice about the fact that their milk has vitamin D added to it—but it does a lot more than just help your bones.

Physical Health Benefits

Recent decades have seen new evidence pile up in favor of sensible sun exposure. Studies have shown links between low levels of vitamin D and higher rates of numerous diseases, since the body relies on sufficient sunlight for its primary systems to operate efficiently. Vitamin D is essential for optimal cardiovascular, immune, respiratory, and skeletal system function.

Research is ongoing, but studies have indicated that sunlight may provide a significant protective effect for osteoporosis, cardiovascular disease, breathing problems, inflammation, and diabetes. Having higher than average vitamin D levels may even lower your risk of getting COVID-19.

Multiple studies have shown reduced rates in developing various types of cancer (including of the colon and breast) with vitamin D and calcium supplementation.

We all know that sunbathing can feel healthy, restorative, and invigorating, but it turns out that sunlight actually may be the remedy our ancient ancestors thought it was—for both body and mind.

Mental Health Benefits

Strong connections have been found between deficiencies in vitamin D and the risk of various mental health disorders.

Interestingly, these conditions are much more prevalent in areas of the world farther away from the equator (such as in Nordic countries) which are exposed to much less direct sunlight and have far fewer hours of daylight in the winter months.

Depression

Depression is an increasingly common mental illness and a leading cause of disability that affects over 121 million people worldwide and more than 7% of all Americans.

Numerous studies have found lower levels of vitamin D in people who have depression—and that vitamin D supplementation (either via sunlight or through food or supplements) can reduce rates of depression and improve symptoms. Research points to vitamin D's role in regulating serotonin and calcium for its possible therapeutic impact on depression.

It's important to note that the benefit of vitamin D to prevent and treat depression is likely only effective in a person who is deficient in the vitamin to begin with.

A 2020 review found that individuals with the lowest vitamin D levels were at the greatest risk of depression compared with controls. However, the study's authors noted that the strength of the correlation, the exact role of vitamin D in the development of depression, and exactly who can benefit from supplementation (and how much is needed) are still unclear.

That said, researchers point to numerous studies that demonstrate an improvement in mood and a lessening of the symptoms of depression with vitamin D supplementation, including in pregnant women and in children.

Studies also indicate a possible role of vitamin D in other common childhood mental health conditions, including autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD).

Light therapy, a treatment that involves daily doses of intense artificial light, is more commonly associated with treating seasonal affective disorder (see more on this below). It has also been proven effective in treating other forms of non-seasonal depression, including major depression and bipolar disorder.

Studies show that light therapy can be as effective as pharmaceutical treatments. You can buy a lightbox to do therapy at home, which is as easy as flipping a switch.

Schizophrenia

Schizophrenia is a serious mental health condition that causes a person to lose touch with reality, often resulting in psychotic symptoms such as hallucinations and delusions. This adversely affects how people with schizophrenia think and behave.

Researchers have discovered that those with schizophrenia are more likely to have significantly low vitamin D levels and are more likely to live in parts of the world with less sun exposure. Numerous studies have also indicated that insufficient sunlight exposure in infancy increases the risk of developing schizophrenia later in life.

Additionally, studies have demonstrated that of people diagnosed with schizophrenia, those experiencing more acute symptoms have relatively lower levels of vitamin D than those in remission from more severe symptoms.

Seasonal Affective Disorder

Seasonal affective disorder is a type of depression that causes negative changes in mood linked to a change in the seasons, principally occurring in the winter months (called winter-pattern SAD or winter depression).

Much less commonly, SAD can also occur in the summer months, which is called summer-pattern SAD.

Sunlight plays a huge component in SAD, and the mental health disorder is known to affect people living farther North in areas with fewer hours of daylight in far greater numbers than those living closer to the equator.

Vitamin D deficiency is proven to adversely impact serotonin regulation, a brain chemical (or neurotransmitter) responsible for regulating mood and sleep cycle.

Studies show that light therapy is especially effective at reducing symptoms of SAD, with positive effects generally seen within a week of initiating lightbox sessions.

Eating Disorders

Researchers have noticed an uptick in symptom severity and eating disorder occurrences in the darker months of fall and winter, leading to the theory that vitamin D deficiency may play a role in developing these mental health conditions.

Promising evidence indicates the possible benefits of bright light therapy and/or vitamin D supplementation to treat and prevent eating disorders.

A 2016 review found that light therapy specifically benefited both behavior and mood for people with eating disorders (particularly for those with binge-eating and night-eating features).

Researchers believe that the role of vitamin D (along with melatonin) in regulating circadian rhythms and serotonin impacts the development of these dangerous eating disorders.

Many People Are Vitamin D Deficient

While those with specific illnesses related to vitamin D deficiencies clearly benefit from more sunlight, light therapy, or vitamin D supplementation, it is worthwhile for everyone to consider boosting their sunshine and vitamin D consumption quota.

It has been estimated that around a billion people in the world may have deficient or insufficient vitamin D levels. Research shows that many Americans regularly get less than the recommended daily allowance of vitamin D and show deficient levels of the nutrient,

Vitamin D Sources

A key component in giving yourself the sunlight your body craves is determining how much your body is getting, how much you need, and how much vitamin D you're taking in from other sources.

Essentially, the only limiting factor for sunlight is avoiding sunburn and skin cancer risk. You cannot overdose on vitamin D made by your own body via the sun's radiation.

Vitamin D From Sunlight

It's estimated that most people get 90% of their vitamin D from the sun, so it's an important source. But many factors influence how much sunlight you are exposed to, including the season, where you live (such as in a sunny climate or in locations that tend to have cool, rainy, or cloudy weather), and your life circumstances (such as working inside or outside and having a yard or living in a high rise).

Personal preference also comes into play. Some people enjoy the fresh air and outdoor recreation time, while others prefer their free time indoors.

Those with pets and children may naturally be outside more because they go on walks or take their kids to parks and various activities. Some people are more diligent with sunscreen application as well.

So, if you spend much of your day inside and suspect you need more sun, go out and get some—using sun safety measures.

If you live in a place without a lot of direct sun and are concerned about a lack of sunlight's impact on you, talk to your doctor about the possible benefits of using light therapy and/or using tanning beds to safely get some extra rays.

Vitamin D From Food

When natural sunlight is not accessible or sufficient and/or not advised due to your potential for skin damage and skin cancer risk, you may want to consider supplementation by eating vitamin D-rich foods or taking vitamin D supplements. Good food sources of vitamin D include:

  • Egg yolks
  • Fortified foods (such as milk, orange juice, and cereals)
  • Liver
  • Oily, fatty saltwater fish (e.g., sardines, salmon, herring, and mackerel)
  • Red meat

Risks and Other Considerations

For most people, sensible sunlight exposure and vitamin D intake are healthy, but there are some risks to be aware of.

Toxicity

You can purchase vitamin D supplements to increase your intake, but watch your dosage. Be aware that the vitamin D you produce in the skin via sunlight is more efficient than the vitamin D from consumed sources, which tend to lose potency in the absorption process.

Additionally, while extremely rare, there is a small risk of overdosing (particularly with supplements).

Recommended Daily Vitamin D Intake

Vitamin D toxicity can cause elevated calcium levels in the blood, nausea, vomiting, fatigue, and constipation. The recommended daily allowance (RDA) for vitamin D intake is:

  • Infants age 0-1: 10 micrograms (mcg)
  • Age 1-70: 15 mcg
  • Age 70 and above: 20 mcg

It is not possible to overdose on vitamin D derived from the sun.

People With Darker Skin Tones

People of color, particularly those with very dark skin, are at higher risk of vitamin D deficiency because the natural sun protection that the melanin in their skin provides also slows the rate of vitamin D production.

For people with deep skin tones who live farther from the equator and/or don't spend a lot of time outdoors, more vitamin D may be necessary to reach optimal levels.

Skin Damage

Clearly, there is also the need to balance time spent in the sun with protecting the skin from burning.

Stay in direct sun with bare skin only for approximately half the time it would take for your skin to get the beginnings of a very light burn. So, if you estimate your skin might begin to pink up after 20 minutes outside, then aim for a maximum of 10 minutes of exposure.

Always use sunscreen on your face, which is already more prone to daily exposure and the resulting skin damage—and the face is not as adept at making vitamin D. The arms, legs, and trunk offer more skin and less adverse impact of skin damage from brief exposures.

While getting frequent doses of sunlight is vital for your health, be sure to follow safe practices to get it so that you don't end up burned and/or increasing your risk of skin cancer. Regular skin cancer checks with your doctor are also important to make sure your skin stays healthy.

Tips For Getting More Sun Exposure

If you're interested in exploring adding more sunlight (and vitamin D) into your life, particularly to monitor if it impacts your mental health, you might consider a few options.

  • Track your sun exposure: Try keeping a log of how much time you spend outside in direct sunlight, what the weather was like, and how much vitamin D you consume. Write down how more or less sun (and vitamin D intake) makes you feel.
  • Get outside more often: Whenever you need to take a quick break from work or just want to stretch, try doing so outside when it's nice and sunny. Eventually, you may be able to see patterns that help you understand how sunlight may affect your wellbeing. Discuss with your doctor any concerns you may have about your sun exposure and vitamin D levels and how any deficits may play a role in your physical and mental health.

A Word From Verywell

The grandmotherly refrain to "get outside and get some sun" is more than just an old wives' tale. Instead, sunlight (and the vitamin D it lets our bodies make) offers enormous mental and physical health benefits that, for most of us, can be accessed simply by walking out the door. So, if you need a boost, go out and get yourself a regular jolt of liquid gold.

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