Falling Back: Supporting Mood and Memory Through Shorter Days

By Ram Rao, Ph.D., Principal Research Scientist for Apollo Health

As the days grow shorter and nights stretch longer, you might notice subtle shifts in mood, energy, or focus, both in yourself and in loved ones living with Alzheimer’s or cognitive decline. These seasonal changes are real and are closely tied to our brain’s dependence on light, routine, and biological rhythms. The changes stem from reduced sunlight exposure and altered circadian rhythms that regulate sleep, hormones, and brain activity.

Why Shorter Days Affect the Brain

Our brains rely on sunlight to regulate the circadian rhythm, which is our body’s internal clock that controls sleep-wake cycles, hormone balance, and mood. When daylight decreases, melatonin levels rise earlier in the day while serotonin (our “feel-good” chemical) production drops. Research shows that this shift in hormonal levels owing to reduced exposure to natural light can:

• Disrupt sleep patterns, leading to restless nights and daytime fatigue.
• Increase irritability, anxiety, or sadness, particularly in those with cognitive impairment
• Reduce motivation for physical activity, which is vital for brain circulation and neuroplasticity.
• Aggravate “sundowning” symptoms, characterized by late-afternoon confusion or agitation, often seen in dementia.

A 2020 study in Chronobiology International highlighted that maintaining stable light exposure and daily routines improves sleep quality and cognitive function in older adults with Alzheimer’s disease. Similarly, light therapy (exposure to bright light for 30–60 minutes each morning) has been shown to ease depression and stabilize circadian rhythms in dementia care settings.

Caregiver Corner

Remember, these seasonal shifts affect caregivers, too. Fatigue and low mood are common as days shorten. Take time to rest, ask for help, and maintain your own social connections. A rested, supported caregiver is better able to care for someone with memory changes.

A Season of Warmth and Renewal

Though autumn and winter bring longer nights, they also offer opportunities for reflection, connection, and renewal. With small adjustments, more light, movement, and mindful care, this season can remain one of warmth, balance, and brain-boosting activity.