How to keep your mood up as the days get shorter — and how to use artificial light therapy

The shift into fall and winter can feel like a slow dimmer switch: less daylight, later sunrises, earlier sunsets. For many people that brings lower energy, sleep changes, carb cravings, and a darker mood. The good news: there’s strong, practical science showing you don’t have to wait for spring. Strategic use of artificial light (and a few behavioral tweaks) can prevent and treat seasonal dips in mood — if you use the right kind of light, at the right time, in the right dose.

Below is a short, readable summary of what the research says, followed by a simple, usable plan you can start tomorrow.

What the data shows

• Bright light therapy works. Multiple reviews and clinical trials show bright light therapy is effective for Seasonal Affective Disorder (SAD) and can help sub-threshold seasonal mood changes. Many people begin to feel better within 1–2 weeks. PMC+1

• Intensity and time matter. Most clinical protocols use a light box delivering ≈10,000 lux at the user’s eye level for 20–30 minutes each morning. Lower intensities (e.g., 2,500 lux) can work but usually require much longer exposure (often 1–2 hours) to produce similar effects. Mayo Clinic+1

• Morning light is usually best. Exposure soon after waking produces the biggest antidepressant and circadian-stabilizing effects. Studies find morning light shifts the clock and improves mood more consistently than evening exposure. PMC+1

• Spectrum (blue) is complicated. Short-wavelength (blue) light powerfully affects the circadian system (melanopsin pathways), but researchers and clinics often advise caution because blue light can be more retina-active and may carry risks for some eyes. Modern light boxes use broad white light that filters UV and balances safety and efficacy. Yale School of Medicine+1

• Light can help beyond 'classic' SAD. Newer studies suggest bright light may also benefit some non-seasonal depressions as an adjunctive treatment. Consult your clinician if you have a major depressive disorder. American Psychiatric Association

  
  

How to use artificial light therapy most effectively

1) Pick the right device

Look for a light box that delivers 10,000 lux at a realistic sitting distance (usually 12–24 inches). It should filter out UV (important for skin/eyes). Mayo Clinic and clinical programs commonly recommend 10,000-lux devices.

If you can’t tolerate 10,000 lux (brightness discomfort), a longer session with a lower-lux box (e.g., 2,500 lux for ~2 hours) is an alternative — but compliance tends to be lower with long sessions.

2) Time it for the morning

Use the light within 30–60 minutes of waking, ideally during a seated activity like breakfast, reading, or checking email. Morning exposure reliably improves mood and helps align your circadian rhythm. Avoid intense evening sessions unless specifically recommended by a clinician.

3) Dose: duration and distance

Standard: 10,000 lux for 20–30 minutes per morning. If the box gives less lux at your distance, increase time rather than move closer. Don’t stare directly into the lamp; keep it angled toward your eyes while you carry out light, non-visual tasks.

4) Position and safety

Place the light box slightly to one side and angled toward your face, not straight into your eyes. Use it while doing other activities — you don’t need to sit motionless.

Avoid UV-emitting devices. Choose clinically designed boxes that filter UV. If you have eye disease, recent eye surgery, or are taking photosensitizing drugs, check with an eye doctor first. People with bipolar disorder should consult their psychiatrist because light can trigger hypomania/mania in some cases.

5) Dawn simulators and alternatives

A dawn simulator (a lamp that gradually brightens your bedroom over 30–90 minutes before wake time) can help shift circadian timing and improve mood and awakening. Some studies show dawn simulation can be as helpful as light boxes for certain people. Consider combining dawn simulation with morning bright light for stubborn cases.

Who should check with a clinician first?

• People with bipolar disorder (risk of switching into mania).

• Those with eye disease, recent eye surgery, or on photosensitizing medication.

• Anyone with severe depression or suicidal thoughts — light therapy is adjunctive, not a replacement for emergency care or standard psychiatric treatment.

  
  

Common concerns and FAQs

• “Will blue-light at night help?” No — blue light at night can suppress melatonin and disrupt sleep. Therapeutic light for mood is used in the morning, not at bedtime. Also, because blue wavelengths are powerful for circadian effects, clinics often prefer broad-spectrum white light boxes with UV filtered rather than intense blue-only devices.

• “Are there side effects?” Some people get mild eyestrain, headache, or jitteriness. These often improve with dose changes. Stop if you notice vision changes or strong agitation and consult a clinician.

  
  

Bottom line

Shorter days don’t have to mean shorter spirits. The science is clear that morning bright light (10,000 lux for ~20–30 minutes) is an effective, fast-acting tool to lift mood and re-align your body clock. When combined with consistent sleep, daylight exposure, activity, and — when needed — therapy or medication, artificial light therapy is a powerful part of a seasonal mental-health toolkit. If you have any eye disease, bipolar disorder, or major depression, check with your clinician before starting.