How Does Light Therapy Work?

MINNEAPOLIS (WCCO) -- It was wintertime a decade ago. Amber Leong had just started a job in downtown Minneapolis where she arrived at work at 7 a.m. and left at 6 p.m.

"I don't see the sun at all," Leong said, recalling that first winter.

She had grown up in Malaysia, which sits near the Equator, and experienced lots of sunlight each day. In 2003, she moved to Minnesota to attend college, but it wasn't until she graduated that she started noticing the effects the lack of daylight was having on her.

"I was getting pretty upset about things, I was getting down," she said. "I couldn't sleep at night. I was feeling sluggish. I was feeling the winter blahs."

She'd heard about light therapy lamps and bought one for her office. At the time, the lamps were bulky and took up a lot of space on her desk. Her co-workers also thought it was strange.

"They thought I was tanning," Leong said. "They'd come to my office and say, Amber, what is that?"

So, that's when the lightbulb (pun intended) went off. She decided to create a more sleek, chic light therapy lamp. In 2016, she created Circadian Optics.

"It was like a big boost of energy," she said. "I felt more awake faster."

Since the 1980s, light therapy lamps have been used by patients suffering from seasonal affective disorder, a type of depression that's related to the changes in the season.

According to Dr. Ziad Nahas, a psychiatrist with the University of Minnesota, studies have shown light therapy lamps can also be used to help fend off a less serious condition like "winter blues."

"If you're only struggling with those – dragging waking up in the morning and not feeling that great – there are certain aspects where light therapy might be helpful," he said.

There are different theories about why light therapy works, according to Dr. Nahas.

The first is that the bright light, which mimics the sun, interacts with the retina in the back of the eye. That sends a signal to the brain about the body's internal clock. It then musters up a series of hormones that wake a person up, even when it's dark outside.

"In a way, you're tricking the brain telling it the day has started," Dr. Nahas said.

Another theory is that the light impacts the body's level of serotonin, which is sometimes called the happy chemical. Some studies show light therapy can have a direct impact on regulating mood.

"There's a number of different theories and none of them have been completely locked in as the mechanism, so we suspect there's a number of reasons for that," Dr. Nahas said.

Most light therapy lamps filter out harmful UV light, which produces Vitamin D, so they should not be used as a way to incorporate Vitamin D. Dr. Nahas also says people should tell their doctors if they are using light therapy so the doctor can better distinguish between depression and winter blues.

It's best to use the 10,000 Lux (similar brightness to full sunlight) light for 30 minutes each morning. Leong's lamps can be adjusted to a dimmer setting if that's too bright. Dimmer settings have also been shown to work as long as the exposure time is longer.

Users of the lamps are told to not look directly at the light, but rather set is 12 to 18 inches away to the side.

"Incorporate this into your daily routine," said Leon. "We give the rule of thumb – set it next to your computer or cereal bowl."