Albuquerque at sunset
By Rebecca Roybal Jones

Mood Brightener

Doctors Say Light Therapy Can Alleviate Depressive Symptoms – Especially When the Days Grow Short

This stretch of in-between time – where the days are slowly getting longer, and the nights a little shorter – can seem never-ending, especially when Punxsutawney Phil predicted six more weeks of winter.

Until clocks spring forward on March 13, you can light up the long nights with light therapy.

Shanna Diaz, DOShanna Diaz, DO, medical director of The University of New Mexico Sleep Disorders Center, says that using light therapy can help not only with mood but also with sleep. And a lack of sleep can affect your mood, she says.

Light therapy is used for treating depression and for shifting the circadian rhythm in people without depression who have trouble sleeping.

This time of year, seasonal affective disorder, which is related to how much sunlight we’re exposed to, can be problematic for some people because it presents as depression. “But it really is based surrounding the seasons, where it typically gets worse in the winter months,” Diaz says.

“You might be at quite a higher risk if you live, say, in Seattle, rather than in New Mexico. There are people who might move to a place like Arizona or New Mexico, because just having that light helps.”

But even with the extra light here in the Southwest, some people still feel the weight of winter blues more than others, she says.

“When we look at light therapy, there's clear evidence that it's helpful for seasonal affective disorder,” Diaz says. But there’s also evidence that it can improve mood for people with non-seasonal depression, too.

“All the chemicals that either keep us awake or help us get to sleep happen to be the exact same chemicals that mental health providers are trying to balance with behavioral interventions or medications,” she explains. “In other words, the same chemicals that keep you awake or asleep, pretty much are the chemicals that affect your mood as well.”

When there is light coming into our eyes it increases the neurotransmitters serotonin and norepinephrine, she says.

“So, when there’s not as much light, as we see in the winter, it’s great for people who don’t have seasonal affective disorder because they might get more sleep,” Diaz says. “But that activates the secretion of melatonin that occurs at night. That longer duration of melatonin secretion may have something to do with triggering that depression, because you're now getting an imbalance of not having enough serotonin around. And that's not the only thing – there's also genetic components.”

For people who are prone to seasonal affective disorder, the incongruence between the external clock time and the internal circadian rhythm makes it harder for those neurochemicals to stay in balance as well.

Diaz describes it as “a circadian misalignment.”

How to use light therapy

A full-spectrum light rated at 10,000 lux should be used for 20-30 minutes in the morning. Using it too late in the day can interfere with sleep, Diaz says. Light therapy is something you can use while you do other things, such as working on the computer, reading or curling your hair. The 10,000 lux model can be used for both improving sleep and mood, she says.

“What I tell patients is to start with half an hour. If you feel like it's helping but if it's not quite enough, then that's where you could go up to an hour,” she says. “The lower the lux, the more time you’ll have to spend in front of the light.”

It’ll take some patience to adjust your sleep habits, and using the light at the wrong time of day can cause sleepless nights, she warns.

If you’re not quite ready to invest in a light therapy lamp, there’s always natural sunshine, which you can absorb for free.

“Getting earlier morning or earlier daytime sun is good on multiple levels,” she says. “It's good for our brains to be outside, if we're talking about anxiety and mood and depression symptoms.

“Certainly, if you're breaking a sweat and exercising or walking briskly, that's even better, but just being outside around trees, for example, helps us release those happy mood chemicals.”

Any activity you can do to wear yourself out during the day, can help with sleep, too.

“People who get 30 minutes of exercise – on average – per day, or 150 minutes a week, are likely to have better sleep and better mood,” Diaz says. “So it's a win-win.”

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