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The Neuroscience Behind Sunlight's Benefits: A Ray of Hope for Mental Health 🧠
How Sunlight Enhances Mood, Sleep, & Cognitive Performance (7min Read)
Sunlight positively affects key brain regions, including the prefrontal cortex, hippocampus, amygdala, suprachiasmatic nucleus, and striatum.
Sunlight's evolutionary benefits include regulating the circadian rhythm and providing essential Vitamin D for calcium absorption.
Sunlight can improve mood regulation, sleep, cognitive function, and attention, and memory while reducing inflammation and oxidative stress in the brain.
Low Vitamin D levels are linked to an increased risk of cognitive decline and various mental health disorders.
Prioritizing sunlight exposure is important for overall mental and physical health, but caution is necessary to prevent skin damage.
As we start to shift toward Spring in the US, I thought it would be a great time to talk about light and the brain!
Dr. Andrew Huberman, a Neuroscientist from Stanford, is a huge proponent of sunlight & its positive benefits for brain health.
He even puts it in his top 5 most important things for brain & mental health!
So, what’s all the hype for? Let’s find out.
Key Brain Regions Sunlight Effects
Some of the most important areas of our brain that sunlight can affect are:
The Prefrontal Cortex (PFC): Research suggests that sunlight exposure can improve PFC activity, which may lead to better cognitive performance.
The Hippocampus: Research suggests that sunlight exposure may increase hippocampal volume, which could help to protect against cognitive decline.
The Amygdala: Research suggests that sunlight exposure can reduce amygdala activity, which can help to alleviate symptoms of anxiety and depression.
The Suprachiasmatic Nucleus (SCN): This is an area of the brain we haven’t talked about before in this blog! SCN is the master clock of the circadian rhythm and is involved in regulating sleep-wake cycles.
Sunlight, as it turns out, is the primary regulator of the SCN, and can help to synchronize our circadian rhythm, leading to better sleep and overall health.
The Striatum: I don’t believe we’ve talked about this region before either, so the SparkNotes version is that the striatum is involved in reward processing and motivation. Some research suggests that sunlight exposure can increase striatal activity, which may help to improve mood and motivation.
This is obviously not an all-encompassing list, but these are some of the most important regions of the brain to keep in mind for this conversation.
The other thing to keep in mind is that sunlight affects our entire body, not just the brain.
This is why the significance of sunlight on our overall well-being cannot be overstated… It benefits our whole Mind, Brain & Body system!
The Evolutionary Benefits of Sunlight
As humans, we have evolved under the sun, and our bodies have adapted to harness its energy for various physiological functions.
Just about everyone has heard that sunlight helps us synthesize Vitamin D, which helps maintain our bone health and strengthen our immune system.
Something that isn’t talked about as often is how Vitamin D is essential for calcium absorption in the body.
Most people think of calcium and bone health, however, calcium is extremely important inside our nervous system.
Calcium (Ca 2+) is what helps neurotransmitters “transmit” their signals inside the synapses of the brain!
Making sunlight & vitamin D very important in our neurodevelopment as a species.
As we discussed earlier when we talked about the effect sunlight has on the Suprachiasmatic Nucleus (SCN), sunlight is crucial for regulating our circadian rhythm.
This is important because it may have helped us sleep better, and during sleep, our body and brain have time to clean themselves, and more importantly, reconsolidate memories.
Without sleep, we wouldn’t have been able to learn or remember that there’s a tiger near the patch of food we went to yesterday, so we shouldn’t go there again.
This is an oversimplification, but I hope you get my point!
Finally, sunlight can increase nitric oxide production inside of us and has antimicrobial effects.
Nitric oxide can help regulate our blood pressure, decrease neuroinflammation, and strengthen our immune system.
This, paired with sunlight helping deactivate certain kinds of infectious diseases, may have helped our sun-fairing ancestors survive in close contact with other groups of humans!
By now, I hope you can see evolutionarily why sunlight is so freaking important and DEEPLY wired into our neurobiology.
Using Sunlight to Improve Your Mental Health
Considering brain health is mental health, it shouldn’t surprise you that there really are research-backed benefits of sunlight exposure & your mental health!
Serotonin & Mood Regulation
One of the primary ways sunlight affects the brain is through the regulation of serotonin which is a feel-good chemical.
Exposure to natural light, particularly in the morning, triggers the release of serotonin in the brain, promoting a sense of calm and contentment.
Research has also found a link between reduced serotonin levels and seasonal affective disorder (SAD), a type of depression that typically occurs during the fall and winter months when daylight hours are shorter.
By increasing serotonin levels, exposure to sunlight can help alleviate the symptoms of SAD and improve overall mood.
It can also help improve the symptoms of other mood disorders, such as major depressive disorder and anxiety disorders too!
Melatonin, Sleep, and Circadian Rhythms
As we’ve talked about, another significant way sunlight influences our brain is by regulating our sleep-wake cycle or circadian rhythm.
Sunlight exposure, especially in the morning, helps to reset our internal clock, ensuring that we feel alert during the day and ready for sleep at night.
This process is primarily mediated by the hormone melatonin.
Melatonin production is suppressed by exposure to light, particularly blue light, which is abundant in natural sunlight in the morning.
As the sun sets and darkness ensues, melatonin production increases, signaling to the body that it's time for sleep.
Early morning sun gazing is one of the first tools that I suggest for my clients who are struggling with sleep.
If you’re looking for exactly how to do this, I highly recommend Dr. Huberman’s short video on how to add this to your morning routine!
Brain Tool: Dr. Huberman’s Sunlight Morning Routine
Cognitive Function and Neuroplasticity
Sunlight exposure has also been linked to improved cognitive function, which shouldn’t be a surprise based on all of the brain areas we talked about earlier!
Research suggests that regular exposure to natural light can boost learning, memory, and overall cognitive performance.
This connection may be partially attributed to the increased production of brain-derived neurotrophic factor (BDNF) in response to sunlight.
We’ve talked about BDNF before in relation to exercise, but to jog your memory, BDNF is a protein that promotes the growth and maintenance of neurons.
It’s like Miracle Grow for your brain and having more of it in your brain can help increase your brain plasticity.
Attention & Memory
Sunlight can also enhance attention and working memory by modulating the activity of neurotransmitters such as dopamine and norepinephrine.
These neurotransmitters play a crucial role in regulating attention, motivation, and the ability to process information effectively.
For more on how these neurotransmitters help us learn, I’d suggest reading my blog on learning & memory below!
Vitamin D & Brain Health
I talked very briefly about Vitamin D earlier, but that wasn’t to suggest that it’s not one of the most important effects of sunlight can have on our Mental Health!
When our skin is exposed to sunlight, it produces vitamin D, which is then metabolized and utilized by various organs, including the brain.
Vitamin D exhibits neuroprotective properties, such as reducing inflammation and oxidative stress in the brain.
Low vitamin D levels have been linked to an increased risk of cognitive decline and various mental health disorders, including depression and schizophrenia.
This is such an important vitamin that I suggest it for some of my clients who are working through depression or struggle with SAD during the Fall or Winter.
There are injections you can get, IVs, and even tablet forms that are often the easiest way to go about it.
I recommend Performace Lab’s D3 + K2 if you’re looking for a recommendation!
Proceed with Caution
The neuroscience behind the benefits of sunlight exposure is a powerful reason to start adding it into your daily routine more often, however, you must also be careful!
First of all, please never stare directly into the sun… When sun gazing in the morning, look off to the side of it, or just be out in the sun!
Outside getting these 5-10mins of sun exposure on your naked eye, I suggest wearing sunglasses if you’re going to in direct sunlight for prolonged periods of time.
Also, if you’re in the sun too often it can damage your skin, so please be careful and wear sunscreen!
Oftentimes you can get the benefits of sunlight even with sunscreen on.
Overall, in a world where we spend increasing amounts of time indoors and in front of screens, prioritizing sunlight exposure is more important than ever.
I hope that by understanding some of the neuroscience behind sunlight’s benefits, you can make informed lifestyle changes that will improve your mental health!
So, step outside, soak up some rays, and until next time, Live Heroically! 🧠
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