Study: The color of a night light can alter your mood

According to a recent study, mood at night can be affected by the color of a night light.

When it comes to some of the health hazards of light at night, a new study suggests that the color of the light can make a big difference.

In a study involving hamsters, researchers found that blue light had the worst effects on mood-related measures, followed closely by white light.

But hamsters exposed to red light at night had significantly less evidence of depressive-like symptoms and changes in the brain linked to depression, compared to those that experienced blue or white light.

The only hamsters that fared better than those exposed to red light were those that had total darkness at night.

The findings may have important implications for humans, particularly those whose work on night shifts makes them susceptible to mood disorders, said Randy Nelson, co-author of the study and professor of neuroscience and psychology at The Ohio State University.

"Our findings suggest that if we could use red light when appropriate for night-shift workers, it may not have some of the negative effects on their health that white light does," Nelson said.

The study appears in the Aug. 7, 2013, issue of The Journal of Neuroscience.

The research examined the role of specialized photosensitive cells in the retina -- called ipRGCs -- that don't have a major role in vision, but detect light and send messages to a part of the brain that helps regulate the body's circadian clock. This is the body's master clock that helps determine when people feel sleepy and awake.

Other research suggests these light-sensitive cells also send messages to parts of the brain that play a role in mood and emotion.

"Light at night may result in parts of the brain regulating mood receiving signals during times of the day when they shouldn't," said co-author Tracy Bedrosian, a former graduate student at Ohio State who is now a postdoctoral researcher at the Salk Institute. "This may be why light at night seems to be linked to depression in some people."

What people experience as different colors of light are actually lights of different wavelengths. The ipRGCs don't appear to react to light of different wavelengths in the same way.

"These cells are most sensitive to blue wavelengths and least sensitive to red wavelengths," Nelson said. "We wanted to see how exposure to these different color wavelengths affected the hamsters."

In one experiment, the researchers exposed adult female Siberian hamsters to four weeks each of nighttime conditions with no light, dim red light, dim white light (similar to that found in normal light bulbs) or dim blue light.

They then did several tests with the hamsters that are used to check for depressive-like symptoms. For example, if the hamsters drink less-than-normal amounts of sugar water -- a treat they normally enjoy -- that is seen as evidence of a mood problem.

Results showed that hamsters that were kept in the dark at night drank the most sugar water, followed closely by those exposed to red light. Those that lived with dim white or blue light at night drank significantly less of the sugar water than the others.

After the testing, the researchers then examined the hippocampus regions of the brains of the hamsters.

Hamsters that spent the night in dim blue or white light had a significantly reduced density of dendritic spines compared to those that lived in total darkness or that were exposed to only red light. Dendritic spines are hairlike growths on brain cells that are used to send chemical messages from one cell to another.

A lowered density of these dendritic spines has been linked to depression, Nelson said.

"The behavior tests and changes in brain structure in hamsters both suggest that the color of lights may play a key role in mood," he said.

"In nearly every measure we had, hamsters exposed to blue light were the worst off, followed by those exposed to white light," he said. "While total darkness was best, red light was not nearly as bad as the other wavelengths we studied."

Nelson and Bedrosian said they believe these results may be applicable to humans.

In addition to shift workers, others may benefit from limiting their light at night from computers, televisions and other electronic devices, they said. And, if light is needed, the color may matter.

"If you need a night light in the bathroom or bedroom, it may be better to have one that gives off red light rather than white light," Bedrosian said.

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How bedroom color can affect your sleep

An interesting article about how the color your bedroom is painted affects sleep.

Tossing and turning at night? Staring at the bedroom walls instead of drifting off to sleep?

The problem might be the color of your bedroom.

A new survey reports that homeowners whose bedroom walls are painted light blue get the best sleep at night, an average of seven hours and 52 minutes. Purple walls were found to be the least conducive to rest, with people averaging just under six hours of sleep.

This new survey, just released by Houzz.com, was conducted by Travelodge hotel chain of 2,000 guests. Houzz is a website that monitors current trends in architecture, interior design, landscape design and home improvement.

The survey showed how room color can affect sleep, shopping habits and even sex life. Couples in room with a caramel decor reported the most sex, an average of three times a week. Not much magic happened in red bedrooms, where romance dwindled to an average of once a week, according to the survey.

"We have done a lot of spa-blue bedrooms over the last several months, especially in blue and chocolate brown combinations," says Marsha Yessick, owner of Yessick's Design Center in Chattanooga. "It is a restful color. But we've done it so much now I think all of us are trying to use some fresher colors."

Yessick says that, as homeowners look to update their blue-and-chocolate decor, they are keeping the brown tones and pairing them with green, another restful color.

Margie Burgin, owner of Chic Solutions in Hixson, says she has seen the pale blue room morph into a pale turquoise shade paired with brown.

"Now fabric companies are throwing in chartreuse in bed and window fabrics, which gives the blue shade an updated look in yellow-green. Pairing yellow-green with blue-green gives it a new twist," she says.

Ironically, the paint colors so prevalent in new home builds in Chattanooga ranked low on the list. Eric Baker, assistant manager of Sherwin Williams on Dayton Boulevard, says soft gray and taupe shades remain top choices for new home interiors as well as remodeling jobs.

"If you're staying with neutrals, green is always a soothing color to have in the bedroom," Burgin says, suggesting beige or taupe as an accent color.

"Gray has a little bit more contemporary feeling," Yessick believes. "Since we are so traditional in this area, I would say taupe is more frequently used in new homes and remodeling."

She suggests pairing a soft yellow with light gray for an updated look.

The Houzz.com survey also revealed how colors correlated with professions. For example, it found pale blue was the top choice of teachers, builders and civil servants. Bankers leaned toward a gold decor; while people in gray rooms spent the most time shopping online in bed.

CONDUCIVE COLORS

Here are study results on best colors for inducing sleep in a bedroom.

1. Pale Blue: Tops, this color was associated with feelings of calmness such as rippling water or blue sky; it's also said to help reduce blood pressure and heart rate.

2. Warm Yellow: When not used in a vibrantly bright shade, yellow calms nerves, projects a "soothing vibe."

3. Green: Respondents say they woke up "feeling upbeat and positive."

4. Silver: Silver mimics moonlight, "cues brain that it's night."

6. Orange: A surprising choice, warm shades of orange were found to relax muscles and "create a stable, reassuring atmosphere."

7. Gray: Although similar to silver, the color didn't perform as well. "Dreary and depressing, it made occupants feel emotionally isolated and uncomfortable, resulting in restless sleep," says the study.

8. Brown, cream or white: These colors were associated with "workaholics who take their work to bed with them at least three times a week."

9. Purple: Considered elegant, it also was thought to be "overly mentally stimulating." So after a busy work day, it made it difficult to turn off the mind and go to sleep.

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