Long summer days can't come soon enough for people with seasonal affective disorder, but some people don't need to wait. Benefits for them can be found with a daily dose of artificial light.
People with SAD commonly report fatigue, moodiness, irritability and increased carbohydrate cravings from November through March, said William J. Weggel, a Mayo Clinic psychiatrist. Women are more likely to report symptoms, which typically repeat annually.
Researchers believe dwindling daylight disrupts melatonin production and throws off circadian rhythms that control sleep, which leads to the disorder. But symptoms dissipate for some sufferers treated with intense artificial light for about 15 to 30 minutes a day. Light therapy is recognized by the American Psychiatric Assn. and can be used to treat major depression, sometimes along with medication.
It's hard to pinpoint why artificial light perks some people up, Weggel said. "We don't know if it enhances serotonin neurotransmission or melatonin or shifting the whole sleep-wake cycle. All of that is kind of empirical and not all that well researched."
Generally, scientific literature suggests light therapy within two hours of waking, because it could disrupt sleep if done later in the day.
There are many products sold to provide light therapy, but consumers should keep in mind that they are not regulated by the U.S. Food and Drug Administration.
The intensity rating, or lux, in SAD lights generally ranges from 3,000 to 10,000 and filters out ultraviolet light. Opt for a product with 10,000 lux wide-spectrum white light, Weggel said.
Much of the research was done with fluorescent bulbs, so Weggel said he could not compare them to newcomers that use LEDs, or light emitting diodes. "We know white light is safe and side effects are minimal." Side effects can include occasional eye strain and headache, he said.
Here are three products now available.
SunTouch Plus by Nature Bright, $169
Armed with four fluorescent bulbs, SunTouch Plus emits blue-enriched wide-spectrum white light with 10,000 lux. A timer runs at 15-minute increments for up to an hour. My desk lighted up like a Broadway production with a bluish ambience.
SunTouch Plus emits 17,000 Kelvins, a color temperature equivalent to a clear blue sky, said Nature Bright Chief Executive Joshua Chen. Higher Kelvins cast a cooler light quality, Chen said. He recommends sitting about 30 inches away from the light.
Lightphoria Energy Light Lamp, $70
Less than 7 inches wide, this compact device uses 72 LEDs in three intensity settings: 5,000 lux, 8,000 lux and 10,000 lux. The device emits wide-spectrum (white) light and comes with a timer that can be set for 15, 30 or 45 minutes.
The design — the light would easily fit in a suitcase — is ideal for frequent travelers. The manufacturer suggests sitting within 12 to 24 inches of the lamp.
Light Box Daylight Simulator, $159
With three fluorescent bulbs, the Daylight Simulator offers two settings: 7,000 and 10,000 lux of wide-spectrum light and a color temperature of 4,000 Kelvins.
The light stands about 28 inches tall when mounted to its stand and is 16 inches wide. The company suggests placing the lamp about 12 inches away.