Sunshine and Your Brain

This past week, the UK has had a sudden reappearance of clear blue skies, giving us a much needed boost after a dull winter. It's got me thinking about how and why the suns rays connect to us in ways that can have such a dramatic impact on our mood. What are the neurological changes our brains experience when sunlight touches our skin?

I wanted to do a little research on why the sun makes us feel a little better. What's the science behind it? And how do we improve our wellbeing when the sun is hard to see?

In the UK, long working hours, office-based jobs, and a culture that prioritises productivity over wellbeing make it even more difficult to enjoy the small windows of sunlight we get. British weather only compounds this issue—summer can bring weeks of overcast skies and unexpected downpours, while winter offers little more than a brief, grey daylight. Many people leave for work before sunrise and return home after sunset, particularly in winter, limiting their exposure to natural light.

The Science Bit

Serotonin

A study published in The Lancet found that serotonin turnover in the brain was lowest during winter months and increased with greater sunlight exposure (Lambert et al., 2002).  Often referred to as the ‘feel-good’ neurotransmitter, serotonin helps regulate mood, promote feelings of happiness, and reduce anxiety. Low levels of serotonin are linked to depression, which is why Seasonal Affective Disorder (SAD) is common in winter months when sunlight exposure is limited. Spending time outdoors, even on a cloudy day, can help maintain serotonin levels and improve emotional resilience.

Circadian Rhythm and Melatonin

Your body operates on an internal clock known as the circadian rhythm, which governs sleep-wake cycles, energy levels, and cognitive performance. Exposure to morning sunlight helps regulate this rhythm by suppressing melatonin (the sleep hormone) and signalling to your brain that it’s time to be alert and active. In turn, this leads to better sleep quality at night, which is essential for memory consolidation, problem-solving skills, and overall brain function. Research by Zeitzer et al. (2000) highlights the importance of morning sunlight exposure in regulating circadian rhythms and improving mood, energy, and cognitive function.

Vitamin D

A study by Kerr et al. (2015) found that sun-avoidant behaviours among female college students were associated with an increased risk of generalised anxiety disorder. Sunlight is the most effective natural source of vitamin D, a nutrient that plays a vital role in brain function. Vitamin D receptors are found throughout the brain, influencing everything from neurotransmitter production to inflammation regulation. Research has linked vitamin D deficiency to cognitive decline, increased risk of dementia, and even mental health disorders such as depression and schizophrenia. Just 10-30 minutes of sun exposure a few times a week can support healthy vitamin D levels and protect your brain as you age.

Dopamine: The Motivation Molecule

Emerging research suggests that sunlight exposure increases dopamine production, a neurotransmitter associated with motivation, reward, and focus. Higher dopamine levels can enhance cognitive function, boost productivity, and even reduce the risk of neurodegenerative diseases like Parkinson’s. This might explain why spending time outside often leads to a sense of invigoration and mental clarity. Dr. Andrew Huberman of Stanford University notes that morning sunlight exposure can increase dopamine release, contributing to improved mood and cognitive function (Huberman, 2021).

Beta-Endorphins: Natural Painkillers & Mood Enhancers

Exposure to ultraviolet (UV) radiation from sunlight has been shown to stimulate the production of beta-endorphins, which are natural opioids produced by the body. These chemicals help reduce pain, enhance relaxation, and create a sense of well-being, similar to the effects of exercise. A study published in Cell (Fell et al., 2014) found that UV exposure in mice led to increased beta-endorphin production, which contributed to reduced pain sensitivity and an overall calming effect.

Norepinephrine: Alertness & Focus

Sunlight exposure can also increase levels of norepinephrine, a neurotransmitter and hormone involved in attention, arousal, and stress regulation. This could explain why natural light exposure is associated with improved focus and reduced symptoms of ADHD (Rautkyla et al., 2010).

Glutamate: Learning & Memory

Glutamate is the brain’s primary excitatory neurotransmitter, playing a key role in learning and memory. Sunlight exposure has been linked to increased glutamate activity, which may help with cognitive function and mental clarity. Research in Neuropsychopharmacology (Moya et al., 2004) found that sunlight deprivation in rats led to decreased glutamate activity in the brain, suggesting that adequate light exposure is important for maintaining cognitive health.

GABA: Relaxation & Anxiety Reduction

Gamma-aminobutyric acid (GABA) is the brain’s main inhibitory neurotransmitter, responsible for calming the nervous system and reducing anxiety. Sunlight exposure—particularly through its impact on serotonin and melatonin—can help regulate GABA activity, promoting relaxation and emotional balance. To support this, a study by Brambilla et al. (2003) in Biological Psychiatry found that light exposure could influence GABAergic activity, which may contribute to the antidepressant effects of bright light therapy.

But How Does the Sun do That?

Sunlight impacts brain chemistry through three key pathways:

1. Through the eyes, regulating serotonin, melatonin, dopamine, and circadian rhythms.
2. Through the skin, triggering vitamin D production and releasing beta-endorphins.
3. Indirectly, through systemic and hormonal effects, influencing norepinephrine, glutamate, and GABA activity (i.e. the effect of the above two methods has a knock-on effect in how our brain chemicals and neurons interact with each other, stimulating further changes)

Advice for Harnessing the Power of Sunlight

Imagine living in a perfect world - all of these suggestions may be possible! Here is a summary of the advice we are usually given to support our brain function:

• Aim for at least 15-30 minutes of natural sunlight exposure daily, preferably in the morning.

• Take breaks outside, whether it’s a walk in the park or simply sitting by a window.

• If sunlight exposure is limited, consider light therapy as an alternative during darker months.

• Maintain a balanced lifestyle with regular physical activity and a nutrient-rich diet to support brain health.

However, thinking back to the opening paragraph, I recognise many readers would feel the same as myself about this advice.. "Thanks a lot, but I live in Britain!"

Supporting Well-being in Cloudy Climates

For those living in countries with frequent cloud cover, rare bursts of sunshine, and demanding work cultures that limit outdoor time, maintaining wellbeing can be a much bigger challenge.

While sunlight is the most natural and powerful way to regulate mood, there are several safe and legal alternatives that can help boost serotonin, dopamine, endorphins, melatonin, and GABA, even for those who can’t get direct sunlight.

• Maximise Outdoor Time: Even brief exposure to daylight, such as stepping outside during lunch breaks or taking short walks, can help regulate circadian rhythms and boost mood. Aim to schedule outdoor activities, preferably whenever sunlight is available, but even when there is cloud cover.

• Use Light Therapy: Light therapy lamps that mimic natural sunlight can be effective in treating Seasonal Affective Disorder and improving energy levels during darker months (Golden et al., 2005).

• Optimise Indoor Lighting: Using full-spectrum lighting indoors can help simulate natural daylight, reducing the negative impact of artificial lighting on mood and sleep cycles.

• Prioritise Vitamin D Intake: Since natural sunlight may be scarce, supplementing with vitamin D can support brain health and immune function. Foods rich in vitamin D include fatty fish, eggs, and fortified dairy products. Vegan-friendly options include fortified plant-based milks, mushrooms exposed to UV light, fortified cereals, and algae-based supplements (Wilson et al., 2017).

• Encourage Flexible Work Practices: Employers can support employee well-being by promoting flexible work hours or incorporating outdoor break spaces to allow for natural light exposure during the workday.

Additionally - And more specifically:

1. Serotonin Boosters (Mood & Emotional Balance)

• Exercise – Regular aerobic exercise (especially outdoors or near a window) increases serotonin levels. Studies show that even 30 minutes of brisk walking can enhance serotonin (Young, 2007).
• Diet – Eating foods rich in tryptophan (which the body converts to serotonin) can help. This includes:
  • Turkey, chicken, eggs
  • Bananas, nuts, seeds
  • Tofu, soy products, oats
• Light Therapy – Bright light therapy (BLT) mimics natural sunlight and is widely used for Seasonal Affective Disorder (SAD) (Golden et al., 2005).

2. Dopamine Boosters (Motivation & Focus)

• Cold Showers – Exposure to cold water stimulates dopamine production by up to 250% (Shevchuk, 2008).
• Listening to Music – Uplifting or favourite songs trigger dopamine release, creating feelings of pleasure and motivation (Salimpoor et al., 2011).
• Setting Goals – Achieving small tasks triggers dopamine, reinforcing motivation and productivity (Schultz, 2015).
• Diet – Foods rich in tyrosine (a precursor to dopamine) include:
  • Almonds, avocados, dark chocolate
  • Lentils, pumpkin seeds, green leafy veg

3. Endorphin Boosters (Pain Relief & Euphoria)

• Laughter – Genuine laughter releases endorphins, improving mood and reducing stress (Dunbar et al., 2012).
• Dark Chocolate – Contains compounds that trigger endorphin and dopamine release (Nehlig, 2013).
• Spicy Foods – Capsaicin (in chillies) stimulates endorphins, providing a natural "high" (Rozin & Schiller, 1980).

4. Melatonin Boosters (Better Sleep & Relaxation)

• Dim Evening Lighting – Reducing blue light exposure (from screens) 90 minutes before bed helps the body produce melatonin naturally (Chang et al., 2015).
• Herbal Teas – Chamomile, valerian root, and passionflower teas stimulate melatonin and relax the nervous system (Zick et al., 2011).
• Magnesium & Tart Cherry Juice – Magnesium helps convert serotonin into melatonin, and cherries contain natural melatonin (Peuhkuri et al., 2012).

5. GABA Boosters (Calmness & Anxiety Reduction)

• Meditation & Deep Breathing – Studies show that mindfulness meditation increases GABA, reducing stress and anxiety (Streeter et al., 2010).
• Yoga & Tai Chi – Mind-body practices stimulate GABA production, promoting relaxation (Guglietti et al., 2021).
• Fermented Foods – Kimchi, sauerkraut, miso, and kombucha contain probiotics that boost GABA levels via gut health (Tillisch et al., 2013).

Final Thoughts

Even without direct sunlight, there are many lifestyle changes that can support brain chemistry naturally. Whether it's bright light therapy, mindful movement, music, nutrition, or even laughter, we have plenty of ways to boost mood and overall well-being in a safe and effective way.

But sunlight remains the most natural and (sometimes) accessible tool for enhancing brain function, mood, and overall well-being. By making a conscious effort to step outside and soak in natural light, you can support your neurological health and feel more energised, focused, and emotionally balanced. Even in cloudy climates, small adjustments in daily routines can help counteract the challenges of limited sunlight exposure.

So, I hope the sun is shining where you are, to give your brain the gift of daylight— one of the simplest yet most powerful ways to optimise your mental health. But if it isn't, that's okay too, there are other possibilities!

Feel free to reach out to Happy Citta if you'd like a little support or direction!