Sunlight and serotonin

We’re used to hearing about how too much of the sun’s warm rays can be harmful to your skin. But did you know the right balance can have lots of mood-lifting benefits?

Sunlight and darkness trigger the release of hormones in your brain. Exposure to sunlight is thought to increase the brain’s release of a hormone called serotonin. Serotonin is associated with boosting mood and helping a person feel calm and focused. At night, darker lighting triggers the brain to make another hormone called melatonin. This hormone is responsible for helping you sleep.

Without enough sun exposure, your serotonin levels can dip. Low levels of serotonin are associated with a higher risk of major depression with seasonal pattern (formerly known as seasonal affective disorder or SAD). This is a form of depression triggered by the changing seasons.

A mood boost isn’t the only reason to get increased amounts of sunlight. There are several health benefits associated with catching moderate amounts of rays.

Sunlight and mental health

Decreased sun exposure has been associated with a drop in your serotonin levels, which can lead to major depression with seasonal pattern. The light-induced effects of serotonin are triggered by sunlight that goes in through the eye. Sunlight cues special areas in the retina, which triggers the release of serotonin. So, you’re more likely to experience this type of depression in the wintertime, when the days are shorter.

Due to this connection, one of the main treatments for depression with seasonal pattern is light therapy, also known as phototherapy. You can get a light therapy box to have at home. The light from the box mimics natural sunlight that stimulates the brain to make serotonin and reduces excess melatonin.

Exposure to sunlight can also benefit those with:

• other types of major depression
• premenstrual dysphoric disorder (PMDD)
• pregnant people with depression

Anxiety-related disorders and panic attacks have also been linked with changing seasons and reduced sunlight.

Additional sunlight benefits

The sun’s benefits go beyond fighting stress. The following are some of the other reasons to catch some rays:

Building strong bones

Exposure to the ultraviolet-B radiation in the sun’s rays causes a person’s skin to create vitamin D. According to one study from 2008, in a 30-minute period while wearing a swimsuit, people will make the following vitamin D levels:

• 50,000 international units (IUs) in most Caucasian people
• 20,000 to 30,000 IUs in tanned people
• 8,000 to 10,000 IUs in dark skinned people

The vitamin D made thanks to the sun plays a big role in bone health. Low vitamin D levels have been linked to rickets in children and bone-wasting diseases like osteoporosis and osteomalacia.

Cancer prevention

Although excess sunlight can contribute to skin cancers, a moderate amount of sunlight actually has preventive benefits when it comes to cancer.

According to researchers, those who live in areas with fewer daylight hours are more likely to have some specific cancers than those who live where there’s more sun during the day. These cancers include:

• colon cancer
• Hodgkin’s lymphoma
• ovarian cancer
• pancreatic cancer
• prostate cancer

Healing skin conditions

According to the World Health Organization (WHO), sun exposure might help treat several skin conditions, too. Doctors have recommended UV radiation exposure to treat:

• psoriasis
• eczema
• jaundice
• acne

While light therapy isn’t for everyone, a dermatologist can recommend whether light treatments will benefit your specific skin concerns.

Additional conditions

Research studies have revealed preliminary links between sunlight as a potential treatment for several other conditions. These include:

• rheumatoid arthritis (RA)
• systemic lupus erythematosus
• inflammatory bowel disease
• thyroiditis

However, more studies need to be conducted before researchers can conclude that sunlight can be a treatment for these and other conditions.

Sunlight and moderation

While there are a lot of good reasons to get sun, the sun emits ultraviolet (UV) radiation. UV radiation can penetrate the skin and damage cell DNA. This can lead to skin cancer.

Researchers don’t always have an exact measurement for how long you should stay outside to reap the benefits of sunlight. But defining an excess amount of sun exposure depends on your skin type and how direct the sun’s rays are.

People with fair skin typically get a sunburn more quickly than those with darker skin. Also, you’re more likely to get a sunburn going outside when the sun’s rays are more direct. This usually takes place between 10 a.m. and 4 p.m.

According to WHO, getting anywhere from 5 to 15 minutes of sunlight on your arms, hands, and face 2-3 times a week is enough to enjoy the vitamin D-boosting benefits of the sun. Note that the sun must penetrate the skin. Wearing sunscreen or clothing over your skin won’t result in vitamin D production.

But if you’re going to be outside for more than 15 minutes, it’s a good idea to protect your skin. You can do that by applying sunscreen with a sun protection factor (SPF) of at least 15. Wearing a protective hat and shirt can also help.

Outlook

From treating skin conditions to improving mood, sunlight has many benefits. If you live in higher latitudes with little sunlight, a light box may provide some of its mood-boosting benefits.

Because excess sun exposure is linked with increased skin cancer risk, don’t stay outside too long without sunscreen. If you’re going to be outside for longer than 15 minutes or so, you’ll need a sunscreen with an SPF of at least 15.

Originally published on Healthline April 1, 2019. Written by Rachel Nall, MSN, CRNA. Medically reviewed by Timothy J. Legg, PhD, PsyD. Republished with permission.

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