12/04/2025
As the days get shorter and sunlight decreases in the fall and winter, rates of depression, anxiety, fatigue, and sleep disturbance increase. This pattern is well-documented in the medical literature and is partly driven by changes in light exposure that affect the brain’s circadian rhythm.
This is not just a “vitamin D issue.” Reduced exposure to natural light disrupts the circadian rhythm, which regulates sleep, cortisol release, melatonin production, and many hormone systems in the body. When this internal clock becomes misaligned, it can contribute to mood disorders, low energy, brain fog, appetite changes, and poor sleep.
Light therapy (bright light therapy or “happy lamps”) is an evidence-based treatment for seasonal affective disorder (SAD) and circadian rhythm disorders. Research shows that daily morning exposure to 10,000-lux light therapy can significantly improve depressive symptoms, support healthy sleep patterns, and improve energy levels. Wearable light therapy devices that deliver targeted light to the eyes have also been shown to affect circadian regulation.
Used correctly, light therapy can support mental health, sleep quality, and overall well-being during low-sunlight months.