Practical steps for boosting your 'happy chemicals' in gloomy weather, from a neuroscientist
Welcome to 'Your Brain On...' with Nicole Vignola, Instagram's favourite neuroscientist (@nicolesneuroscience). In this monthly series, the author of REWIRE is going to be filling Women's Health readers in on the latest science and know-how concerning your most complex, mysterious organ.
Her aim? To harness such intel to live your healthiest, happiest life. As winter still drags on, she explains how to harness your happiness.
It’s early February and you’ve probably just about had enough of this misery. We've faced months of cold, darkness and rain. Although spring is close – the sun is slowly extending into evening and you can almost feel the greenery defrosting – it still feels bleak.
If you’re reading this and nodding all the way through, I want you to know that it’s okay to be struggling. You may be suffering from Seasonal Affective Disorder (SAD), which is a measurable shift in brain chemistry triggered by reduced sunlight exposure during darker months. After months of it fogging your mind, it might be at its worst right now, regardless of how close to the light you are.
Understanding SAD and boosting happiness starts with understanding how light influences key neurochemicals and the brain’s internal clock. There are also plenty of actionable science-backed tools to help you combat this feeling so you can emerge into the Spring feeling lighter and brighter.
Serotonin in winter
While serotonin is often called the 'feel-good; neurotransmitter, its primary role is to regulate mood stability rather than to create happiness.
Think of it as a mood modulator that prevents emotional swings, acting as a buffer against anxiety, irritability and depression. Serotonin operates in key brain regions, like the raphe nuclei in the brainstem, fine-tuning communication between brain cells.
Unlike dopamine, which triggers spikes of pleasure, serotonin provides balance, ensuring emotions remain steady. It also influences systems like the limbic system (emotion regulation) and the prefrontal cortex (impulse control).
During the winter months, reduced sunlight disrupts serotonin synthesis because sunlight stimulates production via pathways involving the retina and tryptophan hydroxylase, an enzyme critical for serotonin formation. Without adequate light, serotonin levels drop, leading to mood instability, fatigue and low motivation.
Additionally, serotonin also regulates sleep and energy by influencing melatonin production. When serotonin falters, excess melatonin persists, amplifying lethargy and mood imbalance during darker months.
In essence, serotonin doesn’t create happiness; it prevents emotional chaos. Without its stabilising influence, the brain becomes more susceptible to stress, mood swings, and the emotional low characteristic of SAD.
How to boost serotonin in winter
Maximise Daylight Exposure
Even though winter days are often grey and lack direct sunlight, your brain still perceives daylight, which helps regulate serotonin production. Any exposure to natural light, even when the sun isn’t visible, supports your mood and energy levels.
How to do it:
Spend time outdoors during daylight hours, especially in the morning, to help your brain sync with the natural light cycle.
Aim for a 15-30 minute brisk walk in an open space, like a park or by the sea, where light is less obstructed.
On particularly dark days, or if you wake up considerately early, consider using a light therapy box of 10,000 lux for 20-30 minutes to mimic daylight. Preferably do this in the morning if you can’t get outside first thing.
Consume Serotonin-Boosting Foods
Tryptophan, an amino acid found in certain foods, is a precursor to serotonin production.
How to do it:
Eat foods rich in tryptophan, such as turkey, eggs, salmon, tofu, nuts, and seeds.
Pair these foods with healthy carbohydrates (eg, oats, quinoa, sweet potatoes) to help tryptophan cross the blood-brain barrier more effectively.
Include omega-3 fatty acids (found in fatty fish like salmon, walnuts, and flaxseeds) to support brain health and neurotransmitter function.
Dopamine and your circadian rhythm
Circadian rhythms are 24-hour biological cycles that regulate changes in our mental state, physical state and behaviour. The most obvious example is the sleep-wake cycle, controlled by the brain’s internal clock, specifically the suprachiasmatic nucleus (SCN) in the hypothalamus.
Light exposure signals the SCN to release chemicals like cortisol in the morning, promoting wakefulness and alertness, while melatonin is released in the evening to induce sleep.
Dopamine, the neurotransmitter responsible for motivation and goal-driven behaviour, is also closely tied to circadian rhythms. Research shows that dopamine production and synthesis are regulated by circadian clock genes, meaning its levels naturally fluctuate over the course of the day. In turn, dopamine influences melatonin, further connecting motivation to the sleep-wake cycle.
This relationship is significant: feeling motivated to achieve your goals peaks at specific times when dopamine systems are most active, typically earlier in the day. Disrupting this system, through inconsistent sleep, lack of natural light or inactivity can impair dopamine regulation, reducing energy, focus and productivity.
In winter, reduced sunlight disrupts this delicate balance. Extended darkness causes excess melatonin release, leading to lethargy and grogginess, while lower light exposure reduces dopamine levels, diminishing motivation and enjoyment. Together, these changes contribute to the symptoms of SAD, leading to a cycle of low energy, poor focus and mood instability.
The catch-22 is that to maintain energy levels and focus, one must continue to embark on the very activities that we don’t want to partake in.
How to boost dopamine in winter
Regular exercise
Regular exercise is one of the most effective ways to boost dopamine and overall brain health. Physical activity increases dopamine release and enhances the sensitivity of dopamine receptors, improving mood, motivation and energy levels.
Exercise also stimulates the production of Brain-Derived Neurotrophic Factor (BDNF), a protein that supports the growth and survival of brain cells. Higher BDNF levels are linked to improved mood, reduced stress and better cognitive function, making it a powerful tool for combating lethargy and low mood. Importantly, these effects build over time, so consistency is key.
How to do it:
Aim for 150 minutes of moderate activity (eg, walking, cycling) per week
Incorporate resistance training at least twice per week.
Short on time? Even 10-minute bursts of movement can increase dopamine and BDNF, leading to immediate and cumulative mood benefits.
Dopamine-driven hobbies
Engaging in hobbies that involve small achievements or creative tasks stimulates dopamine by activating the brain’s reward pathways. Simple, structured hobbies provide quick wins that keep motivation and pleasure levels steady.
How to do it:
Opt for activities like playing an instrument, dancing, puzzles, knitting, sketching, or short creative bursts that offer tangible progress.
Set small, achievable milestones within your hobby — like completing a 5-minute drawing or finishing part of a puzzle — to get a steady stream of dopamine hits.
With these tips, you should be able to get out of your winter funk in time for spring. Even when the sun lasts longer and you can ditch the coats, keeping up these healthy habits are vital for year-round health and keeping you in good stead for next winter. For now, enjoy the easier months.
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