‘Blue’ Light Could Help Teenagers Combat Stress

A new study shows that exposure to morning short-wavelength “blue” light has the potential to help sleep-deprived adolescents prepare for the challenges of the day and deal with stress, more so than dim light. (Credit: © Beboy / Fotolia)

ScienceDaily (Oct. 22, 2012) — Adolescents can be chronically sleep deprived because of their inability to fall asleep early in combination with fixed wakeup times on school days. According to the CDC, almost 70 percent of school children get insufficient sleep — less than 8 hours on school nights. This type of restricted sleep schedule has been linked with depression, behavior problems, poor performance at school, drug use, and automobile accidents. A new study from the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute shows that exposure to morning short-wavelength “blue” light has the potential to help sleep-deprived adolescents prepare for the challenges of the day and deal with stress, more so than dim light.

The study was a collaboration between Associate Professor and Director of the LRC Light and Health Program Mariana Figueiro and LRC Director and Professor Mark S. Rea. Results of the study were recently published in the open access International Journal of Endocrinology.

Levels of cortisol, a hormone produced by the adrenal gland, follow a daily 24-hour rhythm. Cortisol concentrations are low throughout the day reaching a broad minimum in the evening before rising slowly again throughout the night. In addition to this gradual elevation of cortisol at night, cortisol levels rise sharply within the first 30 to 60 minutes after waking. This is known as the cortisol awakening response (CAR). In nocturnal animals, the cortisol spike occurs at night, at the start of activity. It appears to be associated with the time of transition from rest to activity, upon waking. A high CAR has been associated with better preparedness for stressful and challenging activities.

“The present results are the first to show that low levels of short-wavelength light enhance CAR in adolescents who were restricted from sleep,” said Figueiro. “Morning light exposure may help to wake up the body when it is time to be active, thus preparing individuals for any environmental stress they might experience.”

Short-wavelength light has been shown to maximally suppress production of nocturnal melatonin and phase shift the timing of the biological clock. The effect of short-wavelength light on other biomarkers has not been widely studied.

The study included three overnight sessions, at least one week apart. All participants wore a Dimesimeter on a wrist band to measure light exposure and to verify the regularity of their activity/rest periods during the three-week study. The Dimesimeter is a small calibrated light meter device developed by the LRC that continuously records circadian light and activity levels. During the study, adolescents aged 12 to 17 years went to sleep at 1:30 a.m. and woke up at 6:00 a.m., a 4.5-hour sleep opportunity. Each week, participants either experienced morning short-wavelength blue light (40 lux of 470-nanometer light) or remained in dim light.

“We found that exposure to short-wavelength blue light in the morning significantly enhances CAR in sleep deprived adolescents, more so than dim light,” said Rea. “Morning exposure to short-wavelength light may be a simple, yet practical way to better prepare adolescents for the challenges of the day.”

 

http://www.sciencedaily.com/releases/2012/10/121022112847.htm

Coffee’s aroma kick-starts genes in the brain

Re-Post for Filing 2008

Contact: Michael Woods
m_woods@acs.org
202-872-4400
American Chemical Society

IMAGE:Scientists report that the simple inhalation of coffee by rats has changed their gene expressions in ways that help reduce sleep deprivation-induced stress.Click here for more information.


Journal of Agricultural and Food Chemistry

Drink coffee to send a wake-up call to the brain? Or just smell its rich, warm aroma? An international group of scientists is reporting some of the first evidence that simply inhaling coffee aroma alters the activity of genes in the brain. In experiments with laboratory rats, they found that coffee aroma orchestrates the expression of more than a dozen genes and some changes in protein expressions, in ways that help reduce the stress of sleep deprivation. Their study is scheduled for the June 25 issue of ACS’ bi-weekly Journal of Agricultural and Food Chemistry.

Han-Seok Seo and colleagues point out that hundreds of studies have been done on the ingredients in coffee, including substances linked to beneficial health effects. “There are few studies that deal with the beneficial effects of coffee aroma,” they note. “This study is the first effort to elucidate the effects of coffee bean aroma on the sleep deprivation-induced stress in the rat brain.”

In an effort to begin filling that gap, they allowed lab rats to inhale coffee aroma, including some rats stressed by sleep deprivation. The study then compared gene and protein expressions in the rats’ brains. Rats that sniffed coffee showed different levels of activity in 17 genes. Thirteen of the genes showed differential mRNA expression between the stress group and the stress with coffee group, including proteins with healthful antioxidant activity known to protect nerve cells from stress-related damage. — MTS

ARTICLE #1 FOR IMMEDIATE RELEASE
“Effects of Coffee Bean Aroma on the Rat Brain Stressed by Sleep Deprivation: A Selected Transcript- and 2D Gel-Based Proteome Analysis”

DOWNLOAD FULL TEXT ARTICLE
http://dx.doi.org/10.1021/jf8001137

CONTACT:
Han-Seok Seo, Ph.D.
Seoul National University
Seoul, South Korea
Email: abc6978@empal.com