Light at Nighttime Causes Obesity (relevant to timing qi practice)

note: this study is really about needing to follow day and night cycles of nature, and how they affect your meridian flow and thus your metabolism. – michael

LIGHT AT NIGHT COULD BOOST WEIGHT GAIN
By Emily Sohn
Discovery News
October 11, 2010

http://nhne-pulse.org/health-lights-at-night-may-cause-weight-gain/

http://news.discovery.com/human/light-obesity-weight-gain.html

………….

– Exposure to light at night may contribute to weight gain and rising rates
of obesity.

– Even dim light exposure may cause a shift both in when you eat.

– When you eat may be important as what you eat and how much.

– To avoid gaining extra pounds, you may want shut the shades and turn off
lights at night, including computers, TVs and phones.

………….

To avoid gaining weight, suggests a new study, we may need some darkness.

Mice exposed to light at night gained 50 percent more weight than mice whose
nights were truly dark, the study found, even though the two groups ate
equal amounts of food and got the same amount of exercise.

What seemed to matter most was the timing of their meals. With exposure to
nighttime light, the study found, mice ate at times when they normally would
be sleeping. That alone could have altered their circadian rhythms and led
to weight gain. Dim lights had the same effect as bright ones.

While the mice in this study were nocturnal, the same could prove true in
people. That would emphasize the need to shut the shades and turn off lights
at night, including computers, TVs and smart phones — not just to help with
sleep, but to help us keep our figures.

“With the advent of electrical lighting at the turn of the 20th century,
individuals of many species, including humans, became exposed to bright and
unnatural light at night,” said lead researcher Laura Fonken, a behavioral
neuroscientist at The Ohio State University in Columbus. “Our findings are
important because they demonstrate how modern societal developments can
impact health.”

Fonken and colleagues noticed that rates of obesity have risen alongside a
rise in light levels at night. They wondered if the parallel trends might be
more than a coincidence.

The researchers conducted two experiments. In the first, they exposed one
group of mice to 16 hours of light during the day and eight hours of
complete darkness at night. A second group of mice experienced the same
daytime light exposure with eight hours of dim light — at a level that was
like having a computer on in the room. A third group got 24 hours of bright
light.

After eight weeks of being able to eat as much as they wanted, all three
groups gained weight. But mice that had been exposed to light at night
gained an average of 12 grams, compared to a gain of eight grams in the mice
whose nights were dark. The light-exposed mice also had greater trouble
regulating blood sugar levels.

All of the mice, which were nocturnal, consumed about the same number of
calories and got the same amount of physical activity. But those exposed to
light at night ended up eating 56 percent of their calories during daytime
hours, the researchers report today in the Proceedings of the National
Academy of Sciences. Those that experienced true darkness ate just 37
percent of their calories during the day.

To test the idea that timing of meals might make a difference in weight
gain, the researchers again exposed groups of mice to the three light
scenarios. This time, meals were restricted to times of day when the animals
normally eat. In that case, mice didn’t gain weight, even if they
experienced late-night lights.

“I think this has really important implications for weight control and how
we approach weight and diet,” said neurologist Phyllis Zee, director of the
Sleep Disorders Program at Northwestern University in Chicago. “Maybe this
should be a bit of a wake-up call when we’re looking at weight-management
strategies — to think about timing.”

The study could be an important insight in the fight against obesity in
young people, Zee said, because teenagers naturally tend to fall asleep
later and are fiends for their electronic devices. The findings could also
help explain why shift-workers suffer such high rates of obesity, diabetes
and other metabolic disorders.

For everyone, Zee said, the new study underlines the need for good sleep
habits. Around 9:30 p.m., she said, it’s a good idea to shut off
electronics, dim overhead lights and start winding down.

“Now we have another reason to pay attention (to good sleep hygiene),” she
said. “Not only because it can help you sleep better, but because it can
also help us maintain our weight.”