For ages, we’ve embraced the fact that sunshine offers both healing and harmful effects for the body. In excess, sun exposure poses a danger to your health. For example, the sun can damage our DNA in the skin, causing advanced aging, sun damage, and an increased risk for skin cancer.
However, as research continues to advance, complete sun avoidance is proving to contribute to a variety of health complications as well. In moderation, sunlight offers a myriad of well established health benefits, including vitamin D production, improved mood, sleep quality, and decreased blood pressure. But how is this so? Let’s delve into this relationship further
1. Vitamin D production
The most popular known benefit for moderate sun exposure is vitamin D production. Our skin contains a precursor for vitamin D. When exposed to UVB rays, the first step in the process of activating vitamin D begins. This process is incredibly efficient. In fact, we naturally produce thousands of units of vitamin D when exposed to brief, full body sun exposure.
Every system in our body interacts with this important nutrient, from our immune system, reproductive tract, muscle and bones, to name a few. In addition, vitamin D deficiency is linked with over 45 chronic health conditions, and healthy levels help improve immunity, chronic pain, athletic performance, fertility, cognition, and so much more.
Why you may be deficient, despite spending time outside
Did you know, a variety of factors prevent natural vitamin D production from taking place, even if you spend time outside? If any of the following scenarios speak to you, this may explain why:
- Sunscreen use – Sunscreen blocks vitamin D production
- Time of day outside – We require UVB rays to make an abundance of vitamin D, which is most intense when the sun is at its highest point.
- Clothing coverage – Clothing prevents absorption of UVB rays that stimulate vitamin D production.
- Time of year – UVB levels are significantly lower during winter months, dropping our ability to naturally synthesize vitamin D.
- Latitude – As we get further away from the equator, the less vitamin D we can produce naturally.
- Age – As we age, we have less of the precursor for vitamin D available in our skin.
- Skin type – The vitamin D precursor in our skin competes with our melanin, and the more melanin we have, the darker our skin tone will be. This means, those with darker skin tone require more time in the sun to produce an abundance of vitamin D.
2. Sleep Quality
Our internal clock that helps determine our sleep/wake patterns are known as our circadian rhythm. This system is tightly synchronized with sunlight. For example, when the sun rises, our body releases hormones and other chemicals to trigger us to become active; whereas sunset stimulates chemicals to be produced to make us sleepy, such as melatonin.
Though both natural and artificial light can impact our circadian rhythms, daylight has much more intense influence on this important system. That’s why it comes to no surprise to learn that exposure to sunlight enables people to sleep more deeply the following night. In addition, researchers discovered that the earlier people are exposed to the sun in the day, the earlier they will fall asleep in the evening.
3. Boosts mood
Do you ever wonder where the term ‘sunny disposition’ came from? Well, it turns out, this is more than just a phrase to express an uplifting mood. Sunlight exposure may stimulate the increase of specific hormones and neurotransmitters, including serotonin.
Also known as the ‘feel good’ hormone, serotonin is associated with overall mood and state of wellbeing. When we expose ourselves to sunlight, research suggests the brain releases serotonin. In addition, our skin contains serotonin. Though unclear, one study discovered UVA exposure stimulated serotonin production directly from the skin. This may at least partially explain the positive effects of the sun on overall mood.
4. Lowers blood pressure
High blood pressure is incredibly common. In fact, about 45% of the adult population have been diagnosed with this condition. Recent studies suggest sunlight may offer a free, simple way to help lower blood pressure.
Our bodies store nitric oxide in the top layers of our skin. Nitric oxide relaxes the inner muscles of our blood vessels, enabling them to widen, increase blood flow and reduce blood pressure. Sunlight increases the nitric oxide activation in our skin, thereby lowering blood pressure.
As discussed earlier, vitamin D status is a great indicator of overall sun exposure. It’s also linked with a wide range of chronic health conditions, including hypertension. One study looked into this relationship further. They observed a 12% decrease in hypertension rist for every 10 ng/ml increase in vitamin D levels. Another study found that blood pressure rises 2.5 mm Hg for every 10 degrees further away one lives from the equator.
Let’s talk about safe exposure sun habits
Now that we’ve delved down the rabbit hole of how moderate sunlight positively impacts our health, let’s discuss simple ways to ensure you’re practicing safe sun habits.
With that said, we all respond to sunlight differently. That’s why it’s important to listen to your body and health provider prior to making any changes to your sun habits. Generally speaking, many health experts recommend referring to the UV index. This tool predicts the intensity of solar radiation based on your location. On a scale of 0 – 11, a low number on the UV index indicates a lower risk for damaging effects from unprotected sun exposure. It’s not advised to burn or even tan to receive the abundance of health benefits from sunlight.
Some sun exposure guidelines to consider
To get a general idea of how much time is safe for you to be in the sun without burning, simply refer to the below chart to determine your standard erythemal dose (SED). This number defines the average amount of time you may be exposed to the sun before you experience reddening of the skin.
For example, the UV Index in Denver, Colorado today is 8. To get the number of minutes you may safely spend out in the sun, divide the UV Index by the SED. According to this chart, someone with fair skin (type 2 skin type) may begin to experience erythema within 13 to 24 minutes of sun exposure.
However, our bodies make enough vitamin D naturally in just half the time it takes to reach your SED. Using the above example, that would be between 6.5 to 12 minutes for a fair complected person. After this, experts typically recommend applying sunscreen, covering your skin with protective clothing, or avoiding the sun to protect your skin from possible damaging effects.
Take away
In recognition of UV Safety Month, our team highlights both sides of the coin in terms of safe sun exposure. In moderation, research supports a range of health benefits of sun exposure. These include, but are not limited to, vitamin D production, sleep quality, mood, and blood pressure regulation.
With that said, it’s important to practice safe sun habits to minimize risk of harmful effects. This includes modest sun exposure, followed by sunscreen use, UV protective clothing and hats, or going indoors.
To determine your vitamin D needs are being met naturally, testing is key. If you are considering changing your sun exposure habits, it’s important to speak to your healthcare provider, and practice moderation.
Citation
Sturges, Missy. Four key health benefits from safe sun habits. Go Integrative Health, 2021.