September 2025 Newsletter | Seasons Change Our Brains
My mission is to be the first woman in 4 generations to not develop Alzheimer’s Disease (AD). On my journey of discovering ways to mitigate my risk, I pass this information on to you in this Brain-Body-Health (BBH) Newsletter.
Hello Brain Body Health Citizen Scientists
In Northern California, we are already feeling changes in the air, temperatures cooling, shadows lengthening, fall is on the horizon. This month, we are going to discuss how seasons affect your brain health. We all know to keep seasons in mind for our food choices, but did you know seasons really matter for your brain too?
Why Seasons Matter for Your Brain
When the weather shifts outside, your brain goes through seasonal rhythms. Seasons can have a real impact on brain health, both directly and indirectly. Attention to these changes can help you stay sharp, balanced, and energized year-round. Here are some key reasons why it’s important to keep them in mind:
1. Light Exposure and Circadian Rhythms
Daylight length changes with the seasons, affecting sleep-wake cycles and hormone regulation (melatonin, serotonin, cortisol). See Brain Body Health's April newsletter.
Reduced sunlight in fall and winter can lead to seasonal affective disorder (SAD) or low mood due to less serotonin and vitamin D.
2. Vitamin D and Neuroprotection
Sunlight helps the body produce vitamin D, which supports brain health, cognition, and mood. Low levels (common in winter) are linked to depression, brain fog, and fatigue.
3. Seasonal Nutrition
Fresh, seasonal fruits and vegetables provide antioxidants, healthy fats, and micronutrients that protect the brain. For example, berries in summer support memory, while winter greens provide folate and vitamin K for cognitive function.
4. Temperature and Physiology
Extreme heat (summer) can increase the risk of dehydration and heat-related stress, which impair attention, memory, and decision-making.
Cold (winter) can lower physical activity and social interaction, both of which are crucial for brain resilience.
5. Physical Activity and Lifestyle
People tend to exercise more outdoors in spring/summer, boosting blood flow and neuroplasticity.
In colder or darker months, sedentary behavior may increase, which can negatively affect brain health if not balanced with indoor movement.
6. Immune and Inflammatory Cycles
Seasonal changes influence immune function. For instance, flu season (winter) or allergy season (spring) can indirectly affect sleep, mood, and mental sharpness.
7. Social and Emotional Rhythms
Holidays, seasonal traditions, and shifts in social activity influence mental well-being. Connection supports cognitive resilience, while isolation (more common in winter) can harm it.
How Autumn Affects Our Brains
Autumn is a season of transition, and your brain feels it. As the days grow shorter and sunlight decreases, your body produces less serotonin — the neurotransmitter that supports mood — and more melatonin, which can make you feel sluggish and sleepy. This shift can sometimes trigger seasonal affective disorder (SAD) or a dip in energy and motivation. At the same time, the “back-to-routine” pace of fall, with school and work demands ramping up, can add stress that challenges focus and memory. Cooler temperatures may also reduce outdoor activity, limiting one of the brain’s best supports: movement that boosts blood flow and sharpens thinking. On the flip side, fall’s harvest brings an abundance of brain-friendly foods like apples, squash, nuts, and leafy greens, which provide antioxidants, omega-3s, and vitamins that protect memory and cognition. In short, fall can test the brain with mood shifts and stress, but it also offers seasonal tools to nourish and strengthen mental health.
Brain Health Tips for Fall
Maximize Light Exposure: Get outside in the morning for natural sunlight, or consider a light therapy lamp if you notice your mood dropping.
Stay Physically Active: Try fall-friendly movement like hiking, walking among autumn leaves, or indoor yoga when it’s chilly.
Eat Seasonal Brain Foods:
Pumpkin & squash → rich in beta-carotene and fiber.
Apples & pears → antioxidants for memory support.
Nuts (especially walnuts) → omega-3s for cognitive function.
Dark leafy greens → folate and vitamin K, both brain-protective.
Prioritize Sleep: Stick to a steady bedtime as darker evenings can disrupt rhythms.
Support Your Immune System: Adequate vitamin C, zinc, and hydration help reduce illness-related brain fog.
Mind Seasonal Stress: Practice grounding routines, like journaling, mindfulness, yoga, Qi Gong, or cozying up with a book to keep cortisol in check.
For me, fall is essentially a reminder to shift gently into slower rhythms, protect our moods from light loss, fuel our brains with nutrient-rich seasonal foods, and tap into rituals and family celebrations to offset isolation.
Living with a “seasonally healthy brain” means paying attention to how light, food, movement, sleep, and social connection shift throughout the year and supporting your brain through those changes. SAD shows us how sensitive the brain is to daylight and routine. But by using tools like light exposure, exercise, balanced nutrition, and social connection, we not only ease SAD but also strengthen long-term brain health. These same habits are the very things linked to lower dementia risk. Supporting your brain through the seasons doesn’t just help you feel better now — it protects your memory and mental sharpness for years to come.
Lessons in Coaching
Seasonal Affective Disorder (SAD):
As the days grow shorter and the light fades, many people notice a shift in their energy and mood. For some, this goes beyond a case of the “winter blues”.
Why It Happens
SAD happens because our brains are highly sensitive to light. With less sunlight in fall and winter, the brain produces less serotonin, the chemical that supports mood, and more melatonin, the hormone that makes us sleepy. This can leave you feeling sluggish, sad, or unmotivated. On top of that, your circadian rhythm — your internal body clock that guides sleep and wake cycles — can get out of sync with the darker days. Lower light also means lower vitamin D, which plays a role in mood and brain health. All of these shifts together create the perfect storm for low energy, carb cravings, brain fog, and even depression.
What Helps
The good news is that SAD is very treatable once you understand what’s going on. As a psychiatrist, I worked with many clients with SAD. The good news is that when properly diagnosed and treated, they quickly improve. Light therapy is one of the most effective strategies: using a special light box for about 20–30 minutes each morning helps mimic natural daylight and reset your body clock. Getting outside daily, even on cloudy days, is another simple but powerful way to boost serotonin. Supporting your body with vitamin D — whether through safe sun exposure, vitamin-rich foods like salmon and fortified dairy, or supplements — can also make a difference. Regular exercise works wonders too, lifting mood and sharpening focus by increasing serotonin and endorphins.
And don’t underestimate the power of social connection. It’s easy to hibernate when it’s dark and cold, but isolating yourself can make SAD worse. Spending time with friends, family, or community — whether through shared meals, walks, book clubs, or even video calls — helps keep your brain engaged and your mood resilient. Human connection itself is a natural antidepressant.
Sticking to a steady sleep routine adds balance, and scheduling enjoyable activities (like hobbies or cozy creative projects) can make winter feel more fulfilling. In some cases, therapy or medication may also be part of the solution.
Bottom line: SAD is your brain’s response to less light, but with the right tools — light, movement, nourishment, and connection — you can support your mood and make the darker seasons feel a lot brighter.
Watch For These Symptoms of SAD
Persistent low mood or hopelessness
Fatigue and oversleeping (“hibernation mode”)
Cravings for carbs and sweets, weight changes
Trouble concentrating, brain fog
Social withdrawal (“cocooning”)
In more severe cases, thoughts of worthlessness or self-harm (important to seek professional help if this happens)
Brain-Healthy Strategies for SAD
1. Light Therapy (Gold Standard)
A light therapy box (10,000 lux, used in the morning) can mimic natural sunlight, helping regulate serotonin and circadian rhythms.
2. Get Outside Daily
Even cloudy-day light outdoors is stronger than indoor light. Morning walks are especially powerful.
3. Support Vitamin D Levels
Check levels and consider supplementation if <50ng/mL.
Eat vitamin-D-rich foods: fatty fish (salmon, sardines), fortified dairy, mushrooms.
4. Stay Physically Active
Exercise boosts endorphins, dopamine, and BDNF (a brain growth factor), helping counteract low mood.
5. Structured Routine
Regular sleep/wake times stabilize circadian rhythms.
Scheduling enjoyable activities combats withdrawal.
6. Nutrition for Mood
Omega-3s (from walnuts, chia seeds, fish) support neurotransmitter function.
Whole grains and leafy greens stabilize blood sugar and reduce brain fog.
7. Professional Support
Cognitive-behavioral therapy (CBT) tailored for SAD is highly effective.
In some cases, antidepressants (like SSRIs) may be prescribed.
SAD is not just “being down in winter” — it’s a biological response to seasonal light loss. But with awareness and proactive habits, it’s very treatable.
SAD and Gender: Why It Can Feel Different
When the days get darker, SAD doesn’t affect everyone in the same way. Research shows that gender plays a big role.
Women
For women, SAD is much more common. In fact, women are about three to four times more likely to experience it than men. The symptoms often look like low energy, oversleeping, carb cravings, and a drop in mood. Hormones such as estrogen and progesterone, which shift naturally during the menstrual cycle or later in life during perimenopause and menopause, seem to make women more sensitive to the seasonal loss of light. Women also tend to have slightly shorter internal body clocks (circadian rhythms), which means the shorter days of winter can throw their sleep-wake cycles off balance more easily. The upside? Women often respond very well to light therapy, which mimics the effects of sunlight.
Men
Men, on the other hand, are less likely to develop SAD, but when they do, the symptoms are often more intense. Instead of oversleeping or craving carbs, men may feel more restless, irritable, or withdrawn. And because men are less likely to reach out for help, their SAD may go unnoticed or untreated for longer. This combination can make SAD especially tough for men who experience it.
Non-Binary & Gender-Diverse People
Research on SAD outside of the male/female binary is still limited, but emerging evidence suggests that both biology and lived experience matter. For people who are transgender, non-binary, or gender-diverse, hormone levels (whether naturally occurring or influenced by hormone therapy) may play a role in light sensitivity and circadian rhythm shifts, just as they do for cisgender women and men. Social factors also matter: experiences of stress, stigma, or isolation — which can already weigh heavily on mental health — may make the seasonal dip in mood feel sharper. While large-scale studies are still lacking, the key takeaway is that SAD can affect anyone, and personalized approaches that consider both biology and identity are important.
Seasonal Brain Health & Dementia Prevention
Supporting your brain through the seasons keeps mood, memory, and energy strong. The same habits that ease SAD also help protect against dementia:
Light & routine keep circadian rhythms stable, reducing cognitive decline risks.
Exercise & nutrition reduce inflammation and support brain plasticity.
Social ties build cognitive reserve, making the brain more resilient to aging.
Takeaway: Living with a “seasonally healthy brain” isn’t just about feeling good now — it’s an investment in long-term memory and mental sharpness.
Lessons from Science
Brainstem Volume and Depression: A 2020 study published in Frontiers in Neuroscience examined the relationship between brainstem volume and seasonal variations in depression.
Cognitive Performance Fluctuations: A 2016 article in Scientific American discussed how brain activity related to attention and memory tasks varies with the seasons.
Seasons and Psychiatric Disorders: The role of seasons in psychiatric disorders and a discussion of variable factors.
Thanks for all your contributions to further Alzheimer’s Disease research. Our family will be on the Walk to End Alzheimer’s, September 20th in San Diego. Its not to late to add to this worthy cause.
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