Have you noticed that simply being outside in the sun makes you feel better? I find I am definitely more peaceful and productive when I have had my dose of nature. Just as plants absorb and metabolise sunlight, we do too. As well as eating and drinking foods to nourish us, we must also have enough light for optimal health. It makes sense that all life forms – us included – have evolved to use the sun to our advantage.
As our skin absorbs the sun’s ultraviolet rays, this allows our bodies to perform functions that keep us well. Researchers at the University of Edinburgh have found that the heart health benefits to being outside far outweigh the risk of skin cancer. They found that when the sun touches the skin, nitric oxide is released. Nitric oxide is an important molecule to help minimise oxidative stress in the body, and has a role in reducing blood pressure. The blood vessel lining can release it under the right conditions and healthy foods like veggies give us the nitrates we need to help make it. Well, amazingly the sun can do this too. And as a reminder, maintaining a healthy blood pressure is important for cutting the risk of heart disease and strokes, which are a much more significant cause of death overall than skin cancer.
When the sun hits our skin, it also triggers our body to make vitamin D, a fat-soluble vitamin that has a variety of functions. Getting a sufficient amount of vitamin D, sometimes called the ‘sunshine vitamin’, is important for the growth and development of bones throughout our lives. In children, a lack of vitamin D can cause rickets and in adults, it can result in osteomalacia, a condition where the bones become softer, leading to pain and risk of fractures.
There are vitamin D receptors all over our body, and it seems to play an important role in regulating our mood, warding off seasonal affective disorder (SAD), balancing our immune system, lowering our risk of diabetes, and even reducing our risk of certain cancers. Incredibly, one study found that vitamin D could also help with the functioning of the brain. It looked at vitamin D levels in more than 1700 men and women in England who were aged 65 and over. The study discovered that the lower their vitamin D levels, the more negatively impacted their performance was in a series of mental tests.
Sun is Nature’s Antidepressant – a blast of sunshine increases the levels of the mood-lifting chemical serotonin. People who work shifts or long hours where they do not get outside may be more at risk of suffering from seasonal affective disorder (SAD), a depressive illness influenced by changing seasonal light levels and frequencies. This is often treated with artificial light from lamps that are designed to mimic natural sunlight.
Sun helps you sleep
Exposure to blue light and photons as part of normal sunlight within the first half hour or so of the sunrise offers the perfect balance of UV and infrared light, encouraging the body to release the feel-good endorphin serotonin.
Melatonin, the chemical in your brain that makes you feel drowsy and fall asleep, can be made in the body from serotonin. Good sleep helps to regulate our immune system, supports cardiac health, and regulates our appetite, among other things. Now we can begin to understand why early morning sunlight is so helpful; it can stimulate the production of melatonin when the time is right and the sun goes down.
What is the impact of artificial light? In a world where we are constantly exposed to bright light, smartphones, tablets and laptops, our body can misinterpret this light as sunlight. This disrupts our natural sleep patterns. One study showed that workers who are exposed to sunlight and bright light during the morning hours experienced more restful sleep at night. But the same cannot be said for bright light exposure at night, when the opposite is true.
That is why it is so helpful to switch off from devices in the evening at least an hour before you go to bed, so your internal body clock is less affected.
Our eyes do not just ‘see’ the world, they also transmit important information to our brains about what hormones we should be producing and when. We don’t yet know the long-term effects of being exposed to blue light all day and all night. But we do know that blue light is particularly penetrating, and is one of the few colours of the light spectrum that is able to penetrate to the back of the retina, unlike UV light. This may increase the risk of degenerative eye disorders involving the retina, with prolonged exposure over time.
The interactions between sunlight, vitamin D, serotonin and our circadian rhythms are complex. Research is even showing that our gut bugs also get in on the act and are affected negatively by disrupted sleep patterns and jet lag.
We are not separate from the world, but instead have an entire planet’s worth of invisible ecosystems within our bodies that connect us to the sun, to the earth and to the nutrients we eat. This is yet another example of how all our body systems work together in harmony for wellness. A crucial yet overlooked part of health is being outside, existing in harmony with the planet’s cycles around the sun.
How to get out in the sun safely
What is a healthy dose of sunlight? While there are many benefits to exposure to sunlight, it is not without the risk of burning and skin cancer. A number of studies actually show vitamin D reduces the risk – and prognosis – of internal cancers. So how can we get the balance right and maintain adequate vitamin D levels for health?
Dermatologists generally recommend spending time in the shade between 11am and 3pm when the sun is strongest between March and October. But the problem is that this time of day is also the most efficient time to experience the most intense UVB rays for vitamin D production. So, going into the sun at those peak times means more vitamin D is produced in less time.
Another factor to consider is the UVA/UVB ratio. This is the amount of UVA radiation we are exposed to compared to the amount of UVB. The ratio increases as the sun sets, and similar to sun beds, this means that hot sun later in the afternoon may actually pose more of a cancer risk than exposure nearer to the middle of the day. This is important to know, because vitamin D is exclusively made by UVB exposure.
So what should we do? It’s so easy to be over-zealous in the scarce UK sun, strip off with abandon, and end up looking like a lobster. In the UK, 13 minutes of midday sunlight during the summer months three times a week is enough to make adequate amounts of vitamin D in a pale-skinned adult. If you have a darker skin tone, you’ll need anywhere between 30 minutes and three hours more sunshine to make enough vitamin D. If you are outside for longer periods consider covering up with cotton clothing, wearing sunglasses, a hat, and wearing sunscreen on exposed areas. I’d recommend using a mineral sunscreen that does not contain chemicals like oxybenzone and octinoxate, which can be harmful for sea life. They are washed into the ocean from our sewage and of course when we swim in the sea wearing sunscreen.
Mineral sunscreens with ingredients like zinc oxide and titanium dioxide will protect you from UVB and UVA radiation and are also good for sensitive skin types because they will not irritate or clog your skin.
So sunscreen is important, but so is vitamin D. Stay safe, and instead of fearing the sun, let’s appreciate its power and enjoy it wisely.