Alois Kolar
 |
| Intellectual zombies |
It is tacit that the role of light is majorly for the purpose of
illumination for working and reading purpose. It’s also observed that
the artificial light available in the office (~100 foot candles) at eye
level is only around 10 percent of the light available in the shade of a
tree on a sunny day. The
decision of using 100 foot candles artificial light is more of a
technology decision rather than understanding the real biological needs
of human beings. In comparison, the amount of light we are exposed for
16 hours in office is equivalent to 1 hour of expose to a sunny day. So
if in the future we come up with a study which states the need of
higher amount of exposure of light for better bone mineralization, then
the society will have a hard time making a decision on it!
Health researcher Colleen M. Story presents the facts on artificial light that you need to know in today's article, 21.04.2015
Natural science of health
Article by Colleen M. Story
When I first arrive for vacation, me being a night owl, I buck the
current. I write, read, or star gaze until around midnight or one
o’clock in the morning. By about the third night, though, I start
getting tired around eleven-thirty, and usually by the time I have to
return to the real world, I’m used to going to bed not long after
sunset.
Our bodies and minds are meant to wake and sleep with the light of the
sun. The invention of artificial light allowed us to alter those cycles,
mostly to our benefit, but recent research has raised some concerns.
It seems too much artificial light can mess up our natural sleep and
wake cycles, and affect hormone production. Recent studies have even
suggested that overexposure may have ties to dermatitis, eye damage, and
serious diseases like cancer and diabetes.
Could it be that our lights are making us sick?
Too Much Artificial Light May Increase Risk of Cancer
The light bulb was invented in 1879. Now, over a century later, there
are many places in the world where humans live in almost a constant
state of illumination, and children grow up unable to see the Milky Way
at night.
We’ve enjoyed benefits like increased productivity, protection from
crime, and the ability to extend our leisure hours. But as time goes on
and we use more and more light later and later into the evening, we’re
also potentially putting our health at risk.
Exposure to too much light at night disrupts our natural circadian
rhythms, and suppresses excretion of melatonin—the hormone that
regulates sleep and wake cycles. As a result, we don’t sleep as soundly,
or as long, which can lead to significant health problems. Research is
also finding that suppressing melatonin may have other risks as
well—some tied to cancer.
Back in 2001, a couple of studies came out that suggested shift work
could increase risk of cancer. The first looked at about 800
participants aged 20 to 74 years who were diagnosed with breast cancer
between 1992 and 1995. These were matched against controls in the same
age groups. Results showed those who did not sleep during the period of
night at which melatonin levels were highest were more at risk for
breast cancer. The graveyard shift, in particular, was associated with a
higher risk that continued to increase the longer the participants
stayed on that shift.
That same year, another study looked at women from the Nurses’ Health Study
who worked night shifts during 10 years of follow-up. They found women
who worked 1–14 years or 15–29 years on rotating night shifts had an
increased risk of breast cancer compared to women who didn’t work night
shifts. The women worked the shifts at least three nights per month, in
addition to days and evenings in the same month.
A few years later, in 2005, the scientific journal Cancer Research published
the results of an animal study showing that artificial light stimulated
the growth of human breast tumors by suppressing levels of melatonin.
They also found that increased periods of nighttime darkness slowed the
growth of these tumors.
Indeed, there seems to be a connection between suppressed melatonin
levels and a potential increased risk of cancer. Artificial light not
only keeps us awake by reducing melatonin levels, but that the reduction
could disrupt other processes in the body, allowing cancer cells to
take hold.
“Evidence is emerging that disruption of one’s circadian clock is
associated with cancer in humans,” said lead researcher David Blask,
M.D., Ph.D, “and that interference with internal timekeeping can tip the
balance in favor of tumor development.”
In 2007, the International Agency for Research on Cancer issued
a press release announcing that after reviewing the evidence, their
expert working group concluded that shift work that “involves circadian
disruption is probably carcinogenic to humans.”
Too Much Light Tied to High Blood Pressure, Diabetes, and Obesity
Researchers have continued to find a connection between overexposure to
artificial light and cancer over the years—and lately, they’ve broadened
the link to include other diseases like obesity, diabetes, and
depression.
In 2010, for example, Reiter et al. found that the disruption of
circadian rhythms, a lack of adequate sleep, and the suppression of
melatonin aggravated weight gain, and were potential contributors to our
current obesity epidemic.
In 2011, researchers found that exposure to electrical light between
dusk and bedtime strongly affected melatonin levels, which in turn,
could affect the body’s ability to regulate temperature, blood pressure,
and glucose levels.
For the study, they took blood samples from over 100 volunteers aged
18–30 years who were exposed to room light or dim light in the eight
hours before bed for five days. Results showed that those exposed to
room light before bed had melatonin appear in their bloodstream about 90
minutes later than those exposed to dim light. Participants who left
lights on during sleep had melatonin levels suppressed by greater than
50 percent.
“Our study shows that exposure to indoor light has a strong suppressive
effect on the hormone melatonin,” said lead researcher Joshua Gooley,
Ph.D. “This could, in turn, have effects on sleep quality and the body’s
ability to regulate body temperature, blood pressure, and glucose
levels.”
In 2013, researchers reported that exposure to artificial light at night
provoked depression-like changes in animal participants, and that these
changes were reversed when the light was removed.
More recently, in March 2015, researchers published another study
asserting that modern life, with all its reliance on artificial light,
could be putting us at risk of cancer, obesity, diabetes, and other
health issues.
Scientists assert that there is inadequate natural light during the day
inside buildings to promote optimal circadian rhythms, and too much
light at night for our systems to sense true dark.
“This results in circadian disruption and alters sleep/wake cycle,” the
researchers write, “core body temperature, hormone regulation and
release, and patterns of gene expression throughout the body.”
Blue Light and Technology
We can’t talk about how light is affecting our health without talking
about technology. All of our gadgets, including computers, laptops,
tablets, and smart phones, emit a powerful blue light that has been
found to be particularly disruptive to melatonin levels.
A 2009 study, for example, reported that participants who wore
blue-blocking glasses for three hours before sleep experienced improved
sleep quality and improved mood when compared to control subjects who
wore yellow-tinted glasses that blocked ultraviolet light only.
An earlier 2006 study also noted that the circadian clock is most
sensitive to blue light (which comes in short wavelengths). They gave
some of participants orange lens glasses that blocked blue light (called
“blue blockers”), while the others received gray lens glasses. They
then exposed all participants to 60 minutes of bright light between one
o’clock and two o’clock in the morning. Those wearing the blue blockers
were protected from melatonin reduction, while those wearing the gray
lenses experienced a 46 percent reduction in their melatonin levels.
The results hold when we look at the effect of our gadgets on our circadian rhythms and melatonin levels.
In 2013, researchers reported that self-luminating displays (like those
in tablets and cell phones) “emit optical radiation at short
wavelengths, close to the peak sensitivity of melatonin suppression.”
Another study a year earlier found that a two-hour exposure to
electronic devices caused melatonin suppression by about 22 percent.
In 2015, researchers compared the effects of reading a regular book with
those of reading an electronic book, or e-reader in the hours before
bedtime. They found that participants using the e-reader took longer to
fall asleep, had reduced evening sleepiness, secreted less melatonin,
experienced circadian rhythm disruptions, and were more likely to be
sleepy the next morning than those who read a regular, printed book.
Change is Coming?
In 2012, the American Medical Association officially recognized
the growing evidence of health problems associated with exposure to
artificial light, and voted to accept the recommendations of a report
from the AMA Council on Science and Public Health. Their action
opened the door to additional research on the issue, as well as to
education programs that will increase awareness, and to the development
of new technologies that reduce the health risks of indoor and outdoor
lighting.
In the meantime, there are a number of things you can do to reduce your exposure to artificial light.
- Get outside: Expose yourself to natural light for
at least an hour every day. Try a morning jog, lunchtime walk, or
after-work activity that gets you out into the sun. The more natural
light you get during the day, the easier it will be to sleep at night.
- Turn off the lights: At least an hour before
bedtime, dim the lights and turn off the television and all
technological gadgets. For optimal results, avoid looking at bright
screens starting two-to-three hours before going to sleep.
- Keep the gadgets out of your bedroom: If you wake
up and immediately check your phone, you’re disrupting your circadian
rhythms and are likely to feel tired the next day. Over time, these
effects could have more serious health consequences. Keep all gadgets
out of your room.
- Choose a real book: If you’re going to read before
bed, you’re better off reading a real book than an e-reader, to save
yourself from the exposure to bright, blue light. Dimmer light with a
more reddish tinge, like an incandescent bulb, is friendlier to your
circadian rhythms.
- Copy the pilots: Pilots have red lights to
illuminate their instrument panels at night. They’re easier on the eyes,
and it turns out red is the least able to affect your melatonin levels.
Look for dim red lights to use at night. Your alarm clock, for
instance, is better if it emits red rather than blue light.
- Consider orange shades: Research has found that
orange-tinted, blue-light-blocking lenses can block blue light—the most
disruptive to melatonin levels. Shift workers and night owls may be able
to reduce the damage by wearing these when possible. (Simply Google
“blue-blocking glasses” to find a pair.)
- Watch where you place the LEDs: LED lights, though
more energy efficient, produce more melatonin-disrupting blue light
than the old fashioned incandescent bulbs. A recent report by ANSES, the
French Agency for Food, Environmental and Occupational Health &
Safety, also raised concerns that LED lamps can cause stress to the
retina of the eye because of the excessive blue light.
- There’s an app for that: If you most work on your
gadgets at night, try software like f.lux, which adapts the colors and
light level on your screen to the time of day or night.
- Brush your teeth in dim light: Remember that even
brushing your teeth under bright lights may affect your readiness to
sleep. Try to install a red light in the bathroom or brush with the
dimmer switch on.
- Darken your room: If you have light coming into
your room during your sleeping hours, do something to correct it. Try
dark, heavy drapes or other ways to block the light out.
|
