How Light Affects Seasonal Mood
Reduced photoperiod in autumn/winter lowers overall daily light dose, shifting circadian timing and impacting serotonin/melatonin balance. Strategic, brighter light early in the day plus warmer, dimmer light at night can reduce symptoms for many people.
Light Therapy Basics
- Intensity: Standard protocols use 10,000 lux at eye level from a certified light box.
- Distance: Typically 30–60 cm from the light box (check device specs).
- Timing: Morning exposure (e.g., within 30–60 minutes of waking) aligns circadian phase earlier, which correlates with improved mood and sleep.
- Duration: 20–30 minutes at 10,000 lux; longer if using lower intensity (e.g., 5,000 lux for ~45–60 minutes).
Consult a clinician before beginning therapy, especially if you have eye conditions, bipolar disorder, or are photosensitive.
Home Setup That Works
- Station the box at breakfast or desk: Keep gaze oriented toward tasks while the box remains in the periphery; ensure measured vertical illuminance at the eyes is near target.
- Stack daylight + electric light: Sit near a window in the morning; add overhead fill (300–500 lux) so the room isn’t cave‑like.
- Use neutral‑cool task lighting for focus: 3500–5000K at the desk; high CRI (≥ 90) improves comfort.
Evening Hygiene
- Dim and warm: Shift to ≤ 3000K and ≤ 150–200 lux after sunset; warm‑dim bulbs help.
- Blue‑light mindful: Prefer amber night lights; avoid high‑blue phone/tablet light 1–2 hours before bed, or use strong warm filters.
Adjunct Strategies
- Light walks: 15–30 minutes of outdoor light in the morning (even on overcast days) can exceed indoor illuminance by 10×.
- Consistent wake time: Reinforces circadian timing with morning light.
- Environment design: Higher vertical illuminance (light on the eye) is more impactful than brightening only the desk surface.
Measuring What Matters
Use a lux app for rough checks, or a handheld meter for accuracy. Target: 10,000 lux at eye level during therapy; 300–500 lux ambient by day; 50–150 lux evenings.
Template Day
- Wake: Open shades, sit by window + run light box 20–30 min.
- Work block: 4000–5000K desk task lighting, 300–500 lux room ambient.
- Post‑sunset: Dim to ≤ 200 lux; switch to 2700K or warm‑dim; use amber night path lights.
Note: Light therapy is a supportive tool, not a diagnosis or treatment plan. If symptoms persist, consult a professional.