Benefits of Sunlight for Vitamin D Status, Mood, Sleep, Immunity & More

We often talk about how to protect yourself from the sun and even the dangers of UV rays, but the benefits of sunlight deserve lots of attention, too. In fact, too little of it can lead to mood issues, fatigue and vitamin D deficiency.

Researchers have even warned that the recommendations to avoid sunlight can actually cause more harm than good.

A 2020 review published in the International Journal of Environmental Research and Public Health stated that “insufficient sun exposure has become a real public health problem.”

Data from past studies also has revealed that not getting enough natural light may be responsible for 340,000 deaths in the United States and 480,000 deaths in Europe per year, along with an increased risk of cancer, metabolic syndrome, Alzheimer’s disease and cardiovascular disease, among other major health issues.

Beyond allowing for the synthesis of vitamin D, sunlight benefits mood and boosts happy hormones like serotonin. Without it, we risk cognitive decline and greater susceptibility to disease.

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So, what are the main benefits of sunlight? Getting healthy, moderate sunlight exposure may help the body make vitamin D, support mood and serotonin levels, regulate circadian rhythm and sleep, promote bone and immune system health, support cognitive function, and contribute to overall well-being.

The key is getting enough natural light to support health without overdoing UV exposure and increasing the risk of sunburn or skin damage.

For many people, about 10 to 30 minutes of sunlight on bare skin may be enough to start supporting vitamin D and mood, although the ideal amount depends on skin tone, season, time of day, location, cloud cover and the UV index.

So before covering up and reapplying your sunscreen, be sure you are getting the minimum amount of sunshine in your day.

Benefits of sunlight: What is sunlight good for?

You know that feel-good moment you always get when sitting in the sunlight? Well, there’s a reason for that.

Here’s a breakdown of the top benefits of sunlight for your mental and physical health:

1. Helps the body make vitamin D

One of the biggest benefits of sunlight is that UVB rays help the skin produce vitamin D, often called the “sunshine vitamin.” Vitamin D supports calcium absorption, bone and muscle function, immune health, mood, blood vessel health, and overall wellness.

This is why low sun exposure is one common contributor to vitamin D deficiency, especially for people who spend most of the day indoors, live in northern climates, cover most of their skin, have darker skin tones or get very little midday outdoor light.

2. Protects cognitive function

For a 2009 study published in Environmental Health, data from 16,800 participants was analyzed to research the relationship between sunlight exposure and cognitive function. Researchers found that among depressed participants, lower levels of sunlight were associated with impaired cognitive status.

The study indicated an association between decreased exposure to sunlight and increased probability of cognitive impairment.

3. Fights depression

One of the most well-known benefits of sunlight is its positive effect on your mood. Research published in Issues in Mental Health Nursing noted that the treatment of inadequate vitamin D levels in people with depression and other mental disorders may be “an easy and cost-effective therapy which could improve patient’s long-term health outcomes as well as their quality of life.”

Sunlight exposure has shown to increase serotonin levels, which is associated with better mood. Low serotonin levels are associated with seasonal affective disorder, a form of clinical depression that comes and goes in a seasonal pattern.

4. Supports better sleep

Studies have found that there’s a relationship between sunshine and serotonin, a brain chemical that plays a role in mood regulation and many body processes, including sleep.

Another study found that sun exposure plays an important role in maintaining regular circadian rhythm and, because it’s involved in the production of vitamin D, regulates various functions in the body that support restful sleep.

5. Can enhance energy and daytime alertness

Morning sunlight helps signal to the brain that it is daytime, which can support alertness, energy and a healthier sleep-wake rhythm. This is one reason getting outside early in the day may help you feel more awake during the day and sleepier when it gets dark at night.

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Sunlight may also indirectly support physical performance by improving sleep quality, mood and vitamin D status, all of which play a role in healthy muscle function and daily energy.

6. Aids immune system health

Vitamin D performs several roles within the immune system. Studies have suggested that vitamin D deficiency is associated with poor immune function and increased disease susceptibility.

Vitamin D benefits include its role in healthy cell replication and its protective effects against autoimmune conditions.

7. Can bolster bone health

Vitamin D is critical for bone health, and studies have shown that a deficiency is an important health concern. Adequate sun exposure is needed to maintain proper vitamin D levels and optimal bone health, according to researchers.

8. May support healthy blood pressure

Sunlight may also benefit cardiovascular health. Research has suggested UV light can help increase nitric oxide availability in the body, which may help blood vessels relax and support healthier blood pressure levels.

This does not mean sunlight replaces diet, exercise, stress management or medical care for high blood pressure, but it may be one way moderate outdoor light exposure supports overall cardiometabolic health.

9. Promotes longevity

Evidence published in the International Journal of Environmental Research and Public Health cited above suggested that it would be beneficial for people living outside of the tropics to ensure they expose their skin to the sun sufficiently. A lack of sunlight can cause vitamin D deficiency and increase the risk of several major health concerns, including cancer, heart disease and osteoporosis.

Getting adequate sun exposure promotes longevity and improves your mood and feelings of happiness.

10. May help fight cancer

Research published in the Journal of Cosmetic Dermatology pointed out that vitamin D is derived from solar ultraviolet light exposure, and there’s evidence that low levels of vitamin D can increase the risk of 16 different types of cancer, including breast, ovarian and prostate cancers.

11. May help improve indoor environments

There may even be benefits of sunlight indoors.

Sunlight coming through windows will not provide the same vitamin D benefits because most glass blocks UVB rays, but natural light may still support mood, alertness and circadian rhythm.

Some research also has suggested sunlight exposure in indoor spaces can reduce certain bacteria living in household dust, which may help explain why bright, naturally lit rooms often feel fresher.

How to get more sunshine

How much sunlight do you need per day?

This depends on your skin type, location, season, time of day and the UV index. A general target is about five to 30 minutes of direct sunlight on exposed skin several times per week, and many people may benefit from about 10 to 30 minutes on days when safe sun exposure is possible.

People with lighter skin tones may need less time in the sun, while people with darker skin tones often need more time because higher melanin levels naturally reduce UV absorption. As a general guide, lighter skin tones may need about 10 to 15 minutes, while darker skin tones may need closer to 25 to 40 minutes, depending on the UV index and season.

Best time of day to get sunlight

Morning sunlight is especially helpful for circadian rhythm, mood and daytime alertness because it tells the brain that it is daytime and helps set the body’s internal clock. This can make it easier to feel awake earlier in the day and wind down at night.

Midday sun generally provides more UVB rays for vitamin D production, but it can also increase the risk of sunburn when the UV index is high. If you are trying to support vitamin D, keep exposure short, avoid burning, and adjust based on your skin tone, season and local UV index.

In summer months when the index is very high, you can wear sunscreen on your face and other sensitive areas to avoid sunburn, but let your arms and legs soak up the sun for that period of time. During colder months, you can spend a longer period of time in direct sunlight without the risk of burning.

While getting adequate sun exposure is vital to human health, it’s also important to avoid getting a sunburn. Researchers suggest getting no more than five to 30 minutes of direct sun exposure (depending on your skin type and the UV index) during high ambient UV ray seasons to avoid sunburn.

What about indirect sunlight or using a sunlight lamp? When it comes to boosting your mood and promoting better sleep, getting indirect sunlight is beneficial, too.

Sitting by a sunny window definitely has its advantages, for example.

Do you get benefits of sunlight through a window?

Yes, but not all of them. Sunlight through a window can still help brighten your environment and may support mood, alertness and circadian rhythm.

However, most window glass blocks UVB rays, which are the rays your skin uses to make vitamin D. That means sitting by a sunny window is not a reliable way to raise vitamin D levels.

For vitamin D benefits, safe direct outdoor exposure is more effective. For sleep, mood and energy benefits, bright natural light through a window may still be useful, especially in the morning.

If you don’t have access to natural sunlight, using a sun lamp or light therapy box is an effective alternative.

One study found that light therapy is an effective treatment for seasonal affective disorder and has benefits after only 20 minutes of use, which continue for up to 60 minutes.

Easy ways to get more sunlight safely

• Take a short morning walk before work or after breakfast.
• Drink coffee, tea or a smoothie outside.
• Take a phone call or virtual meeting outdoors when possible.
• Eat lunch or a snack outside.
• Exercise outdoors instead of indoors a few days per week.
• Open curtains during the day to increase natural light exposure indoors.
• Garden, walk the dog or park farther away from store entrances to add a few extra minutes outside.

Risks and side effects

The goal is moderate sunlight exposure, not sunburn. Too much UV exposure can raise the risk of sunburn, premature skin aging, dark spots, eye damage and skin cancer.

Protect your skin when you will be outside longer than your brief sun-exposure window, especially when the UV index is high.

Use shade, hats, UV-protective sunglasses, protective clothing and broad-spectrum sunscreen when needed. Reapply sunscreen at least every two hours when outdoors for longer periods and more often if swimming or sweating.

Some medications, including certain antibiotics, acne treatments, diuretics and other prescriptions, can increase sun sensitivity. If you take medication or have a history of skin cancer, photosensitivity, autoimmune disease or other skin concerns, ask your healthcare provider how much sunlight is safe for you.

Exposure to light at night strongly suppresses melatonin, which can interfere with sleep timing and sleep quality. Sources of indirect sunlight may interrupt circadian rhythm and result in sleep disruption.

When it comes to using a sun lamp, excessive use may cause adverse effects, including eyestrain, headache and nausea. If this occurs, reduce the amount of time you use the lamp per day.

Frequently asked questions

What are the benefits of sunlight?

The main benefits of sunlight include supporting vitamin D production, mood, serotonin levels, sleep, circadian rhythm, immune function, bone health, cognitive function, energy and overall well-being.

How much sunlight should you get per day?

Many people may benefit from about 10 to 30 minutes of sunlight on exposed skin, although the right amount depends on skin tone, season, location, time of day and the UV index. The goal is to get enough light to support health without getting sunburned.

Is morning sunlight good for you?

Yes. Morning sunlight is especially helpful for regulating your circadian rhythm. Getting natural light early in the day can support daytime alertness, mood and better sleep at night.

Can sunlight through a window give you vitamin D?

Usually, no. Most window glass blocks UVB rays, which are needed for vitamin D production in the skin. Sunlight through a window may still support mood and alertness, but direct outdoor exposure is more effective for vitamin D.

Can sunlight improve sleep?

Yes. Sunlight helps regulate the body’s internal clock. Bright light during the day, especially in the morning, helps signal wakefulness, while darkness at night supports melatonin production and sleep.

What are the risks of too much sunlight?

Too much sunlight can cause sunburn, premature skin aging, dark spots, eye damage and a higher risk of skin cancer. The safest approach is brief, moderate exposure followed by sun protection when staying outdoors longer.

Conclusion

• Sunlight benefits include supporting vitamin D production, mood, sleep, circadian rhythm, immune health, bone health, cognitive function, energy and overall well-being.
• There’s something very comforting and energizing about sitting in the sunlight. It leaves us feeling refreshed and boosts our mood, but that’s not all sun exposure does for our health.
• Sunlight benefits really come from the production of vitamin D, which plays a critical role in immune system health, bone health, proper sleep and more.
• Healthy sun exposure is highly individual. Skin tone, season, location, time of day and UV index all affect how much sunlight you need.
• A general goal is about five to 30 minutes of direct sunlight on exposed skin several times per week, or about 10 to 30 minutes on days when safe sun exposure is possible.
• Morning sunlight is especially useful for mood, energy and sleep-wake rhythm, while brief midday exposure may be more effective for vitamin D production.
• Avoid sunburn. Use shade, hats, sunglasses, protective clothing and sunscreen when you will be outside longer than your brief sun-exposure window.
• If you don’t have access to direct sunlight, try sitting by a sunny window or using a sun therapy light.