Sunshine is one of the simplest and most healing resources that are available to us. Yet it is often overlooked and lost in our busy modern lives full of screens, time spent indoors and constant rush from place to place. There is also quite a bit of ‘bad press’ and fear surrounding the sun exposure. But it wasn’t always that way. So let’s take a moment to reconnect with the sun and rediscover its incredible benefits.
Vitamin D - the ‘sunshine hormone’
Pretty much everyone has heard about vitamin D. And most people have been diagnosed with vitamin D deficiency at some point in their life. But what exactly is this vitamin D?
Well It is actually a hormone, not just a vitamin, that plays a vital role in immune regulation, bone health, mood balance, sleep and gut health. Unlike most nutrients that we get from food, vitamin D is produced only when our skin is exposed to the UVB rays from the sun. When these rays hit the skin, they convert a cholesterol-based compound into a precursor to vitamin D3, which is then transformed by the liver and kidneys into the active D3 form called calcitriol.
This hormone then travels through the bloodstream to help regulate calcium absorption, support immune cells, reduce inflammation, protect the integrity of the gut lining and much more – basically every function in the body needs vitamin D.
To make enough vitamin D naturally, the skin needs to be regularly exposed to midday sun — without sunscreen for a short period.
What about the UVA?
Sunlight actually has two main components – apart from the UVB that helps us make vitamin D it also has UVA rays. The UVAs are present throughout the whole day and penetrate deeper into the skin. One of their key benefits is helping the body release nitric oxide – an important molecule that improves blood flow which helps lower blood pressure and distribute oxygen and nutrients around the body.
Early morning and late afternoon sunshine is invaluable for gentle support of our nervous system as the UVA increases endorphins – our happy hormones which bring us better mood and emotional regulation.
Yes, too much of UVA, especially through windows or sunbathing too long if our skin is not used to it, can lead to sunburns and contribute to skin aging. But sensible, regular sun exposure in nature should be part of healthy, holistic lifestyle.
Sunshine and Sleep
There is another big reason why we should go out early in the morning – our sleep. Wait a minute, we just woke up, so what does it have to do with sleep? Actually a lot.
The early morning light (even if the sun is hidden behind the clouds as it often is here in UK) enters our eyes and stimulates receptors in the retina. The signal then travels to the suprachiasmatic nucleus in the brain – it is a tiny area in the hypothalamus that is a centre of the body’s circadian rhythm. You can think of it as internal body clock that regulates all physiological and behavioural processes including sleep and wake cycles, hormone levels, body temperature etc.
It also starts a ‘timer’ for melatonin release which should happen 12-14hrs after the first morning light signal in the eyes. Windows, glasses, some contact lenses block this morning blue light and hence may affect melatonin production and sleep.
So if you are struggling with sleep – finding it difficult to fall asleep, stay asleep or you are not waking up refreshed enough in the morning, try this little hack. Go out first thing in the morning, take off your glasses even just for a few minutes and let the daylight and sunshine reset your body clock!
(Note: it doesn’t mean looking directly into the sun!)
The Gut, Brain and Two Serotonins
Melatonin is not the only hormone linked to the sun and daylight. Sunlight is also important in balancing the gut-brain connection through serotonin – the ‘feel good’ hormone and neurotransmitter.
Serotonin is primarily associated with the brain but only 10% of it are actually produced in the brain. About 90% is produced in the gut. Both are important yet they have slightly different functions. The brain serotonin regulates mood, emotions, sleep, memory, attention and impulse control. The gut serotonin on the other hand affects gut mobility, digestion, secretions, gut lining repair and local immune responses as well as the enteric nervous system (aka ‘gut brain’).
So when the natural light hits our eyes in the morning, it signals to the brain to boost serotonin levels. This sets our mood for the day – feeling good, calm, regulates attention and behaviour… It also stimulates the vagus nerve that connects the brain and gut. This communication can contribute to production of serotonin in the gut (there are other mechanisms at play too). That is how the sun can indirectly help improve digestion, gut immune function and nervous system balance.
Even though the gut produces much more serotonin than the brain, the gut serotonin stays in the gut – it cannot substitute the brain serotonin. The brain must make its own and that is why the daylight is so important. And why most of us feel much better when the sun is out 🙂
How much sun do I need?
How long is a piece of string? I am afraid there is no one simple answer to neither of these questions. There are several factors that determine the time each one of us needs on the sun to synthetize enough vitamin D in our skin.
We already talked about the time of the day when the UVB rays are most intense and help us produce more vitamin D in a short amount of time. Another important factor is the season. In the Northern hemisphere the vitamin D rays are of course much stronger in summer while in winter there may be little to now UVB available.
Your geographical location also matters. The closer to the equator the more consistent exposure you can get generating more continuous vitamin D supply. Although we can still get some degree of vitamin D even on cloudy days, clear skies enable maximum production.
Another variable is the altitude. The higher you are above the sea level, the more intense is the UVB radiation so you may get more vitamin D than your friends at sea level within the same time. Also snow, sand and water reflect the rays which can boost your exposure – this might be useful while skiing in winter but it may lead to quicker sunburns when swimming in the sea in summer (also depending on your Fitzpatrick skin type).
Last but not least, probably the most obvious factor is the skin exposure. The more of your skin you expose, the more vitamin D you’ll be able to get in a shorter time.
Even though it is the UVB that provides us with vitamin D, we need to start with the morning UVA too! The morning sun basically tells our brain that the sun is getting warmer so it is time to start producing various neurochemicals and hormones to prepare the skin for receiving the hotter sun later on during the day.
And it is equally as important to limit exposure to artificial light in the evening, wear blue light blockers and keep your sleeping environment really dark so that your body can repair itself during the night and produce plenty of melatonin. All this will help you enjoy the time in the sun during the day and maximise the benefits of your exposure to the UVB.
Bonus tip: There are various apps that can help you determine when is the best time to get your vitamin D and how much time you’d need to spend in the sun. My favourite is My Circadian App.
Enjoy the Sunshine!
Due to our modern life spent mostly indoors most of us are deficient in vitamin D and other elements associated with the sun. More and more research results confirm the link between low vitamin D levels and many chronic health conditions including autism, ADHD, eczema, endometriosis etc.
Apart form low vitamin D people with most of these conditions also have symptoms of disrupted circadian rhythm (poor sleep), imbalanced serotonin (mood and behavioural issues), gut inflammation (leaky gut).
Nature has given us the sun not just for warmth but also for health and rhythm. Gentle, regular sunlight exposure especially in the morning is one of the most powerful, free and effective healing aids. Even simple habits like sitting outside barefoot (for grounding) a few minutes in the morning sun can make big difference 💛
(If you are not used to being in the sun, please start slow and little by little build up your skin resilience to avoid sunburns.)
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