4499 Medical Drive #225,
San Antonio, Texas 78229 210.616.0836
"The Dark Side of
the Sun"
All life on earth depends on the
light reaching us from the sun. Photosynthesis
harnesses the sun's light (remember
Chlorophyll?) and
produces glucose in the plants which are then eaten by animals and since we
are animals we are here because of the Sun. Sunlight keeps
us warm. And we need sunlight to help make
Vitamin D.
And it keeps us from getting
sad as in
Seasonal Affective Disorder.
And it give us
Rainbows. And
we don't stumble over things in the day because we can see
them. So faaaar so goooood..... What's the
catch?
The Sun emits many wavelengths of
the
Electromagnetic Spectrum. Remember your Physics
Class? Here are a couple of diagrams to remind you.
These Electromagnetic Waves vary greatly in their
wavelengths and their energies. It turns out that our
atmosphere blocks out a lot of the deadliest of these waves
because of that neat
Ozone
layer. It is especially good that it stops the gamma
and xrays or we would be vaporized like in Star Trek. Radioactive
elements also emit Xrays and gamma rays and these are both helpful and
potentially harmful.
Remember Chernobyl Disaster?
Only 3 of these wavelengths have
significance for us however, the Ultraviolet, Visible and
Infrared parts of the Spectrum.
Most of the Sunlight
that reaches the Earth is in the Visible and Infrared
regions.
Visible Light
wavelengths, 400-700nm, reach the earth
and bounce
off objects. Our retinas can sense this reflection and we can
distinguish colors. This kind of light is totally
harmless and is what our Intense Pulsed Light device emits.
Visible light, especially the Blue and Red wavelength, is the
light that is used in Photosynthesis (Marijuana growers
understand all this).
(See Article).
The
Infrared wavelengths,
750nm-1mm that reaches the Earth causes 49% of the heating
of the Earth, the rest is from
the Visible light. It is divided into IR-A, IR-B and
IR-C. As can be seen from the diagram above IR-A
penetrates deeper than even UVA. It has been shown
that IR-A produces it's damage by production of Free
Radicals and activation of enzymes (Metalloproteinase, MMP)
that break up and damage collagen and elastin. Visible and Infrared light is
absorbed by the land and water and and us and warms up the earth and as
long as we don't get too warm because of trapped heat (Greenhouse
effect) we're gonna be OK except for the damage
to our Dermal Collagen and Elastin.
Infrared
Saunas use heaters that emit Infrared radiation
that warms the Sauna air, our bodies and/or stones.
Ultraviolet
or UV rays (Ultra = above Violet) also reach the
earth and the rest of this article deals with how UV and
Infrared rays
cause mischief with our skin.
The UV region covers the wavelength
range 100-400 nm and is divided into three bands:
98.7% of the UV radiation that reaches the Earth's surface s
UVA.
UVA (315-400 nm), long wave,
or
Black Light, not blocked by
Ozone layer, Most reaches the earth and penetrates skin deeply
(Dermis). 98.7% of the UV radiation that reaches the
Earth's surface is UVA.
UVB (280-315 nm), medium wave, mostly blocked by Ozone
layer, penetrates thin layer (Epidermis) of skin. SPF refers
to protection against UVB. UVB is required to
produce Vitamin D in our Skin, but this effect only
occurs when the angle of the sun is greater than 50
degrees to the earth. You can see why Vitamin D
deficiencies are so common as many far northern and
southern latitudes get little UV-B penetration so we
don't get Vitamin D production. Go to the
Solar Elevation Angle page and you can calculate when in
the year and at what time the sun is greater than a 50
degree angle for your location. It will usually only be
in the middle of the day and in some locations it is
never greater than 50 degrees. And remember on a cloudy
day we don't get any UVB, and if you wear clothes or
sunscreen or you are elderly you don't produce Vitamin D
either. See
UVB Radiation Definition and Characteristics from
Colorado State University.
A:
Circulating concentrations
of vitamin D3
after a single exposure to 1
MED of simulated sunlight,
with a sunscreen (SPF 8) or
a topical placebo cream. B:
Circulating concentrations
of vitamin D in response to
whole-body exposure to 1 MED
among healthy young and
elderly subjects.
A:
Changes in serum
concentrations of vitamin D
among 2 lightly pigmented
white subjects (skin type
II) (A) and 3 heavily
pigmented black subjects
(skin type V) (B) after
total-body exposure to UVB
radiation (54 mJ/cm2).
C: Serial changes in
circulating vitamin D
concentrations after
reexposure of one black
subject in B to a 320 mJ/cm2
dose of UVB radiation.
UVC (100-280 nm), short wave,
blocked by Ozone layer, very deadly, used to kill
bacteria (Germicidal) as in
Ultraviolet Germicidal Radiation.
See
SteriShoe,
uses UVC to kill germs that cause foot odor and possibly
infections.
UVA and Infrared IR-A rays cause aging of the
skin because they penetrate into the dermis and create free
radicals and activate enzymes which damage our Collagen and
this leads to wrinkles and UVA & IR-A alters our Elastin which
leads to more sagging (Gravity is also a Factor) and all
this makes us look old and our skin can start to look like
leather and kids on the beach stick their tongues out at us.
The UVB rays are the burning rays of the sun
and are
the primary cause of sunburn and skin cancers and UVB
suppresses the immune system which leads to things like cold
sores and cancers and cataracts. Humans vary >100 fold
in their sensitivity to the harmful effects of UV Radiation.
Those who have organ transplants and are on
immunosuppressive drugs have a marked increase in skin
cancers and this is worsened considerably by sun exposure.
In some people, immune suppression occurs very rapidly
making them more likely to develop skin cancer. As the
Ozone layer is depleted, the amount of UVB reaching the
Earth will increase, thus making protection from UVB more
important. Severe Sunburns as adolescents markedly
increase the likelihood of skin cancers later in life.
People with more pigment in their skin have less skin cancer
because the pigment
(Melanin) blocks some of
the rays from reaching the living cells of the skin and
prevents the DNA from being damaged. Tanning of the
skin is therefore a protective mechanism to protect against
UV Rays.
UVA rays also
cause some skin cancer, primarily Melanoma, and a little
burning and tanning too (See
Tanning Beds) but UVA and
IR-A are the primary rays which play a
role in premature aging, characterized by wrinkles, sun
damage, freckles, and skin sagging with the loss of
elasticity. Unfortunately, there are approximately
500 times more UVA rays in sunlight than UVB rays which is
reaching our skin and a lot more of the IR-A. You are
continually exposed to harmful UVA rays even in the winter,
on a cloudy day, or sitting next to a window or in your car.
The effect of UVA and IR-A on our skin is "real time" with immediate
production of free radicals and activation of enzymes which
breakdown our Collagen and alter our Elastin. 98.7% of the
UV radiation that reaches the Earth's surface s UVA.
For details of all this refer these other references.
In case you were wondering, enzymes called photolyses protect plants from UV
Radiation damages otherwise there would be a Plant
Dermatologist Specialty.
See Article.
View movie at FDA of the short and long term effects of UV
exposure. (Requires Flash Player -
Download now)
YouTube "How The Sun Sees You"
Using a camera which sees only UV light!
UV Photography Reveals Sun Damage
We can use ultraviolet (UV)
photography to show our patients how
the sun has damaged the skin. In the
following patient photographs, the
two photographs on the left in each
series were taken in ordinary light
and show what is visible to the
naked eye. The picture on the right
was taken with a UV-light camera and
illustrates the amount of damage
that lies beneath the surface of the
skin.
At age 18 months, sun
damage is not yet
apparent.
At age 4 years, early
sun damage is evident.
Notice the freckling
across the nose
and cheeks.
The photograph above
shows that this
17-year-old already has
significant
sun damage.
This 37-year-old woman
has subsurface sun
damage, which is clearly
visible
in the photo on the
right.
At 52, this woman has
"prematurely aged" skin
in visible light and
significantly
sun-damaged skin in
ultraviolet light.
This 64-year-old beach
community resident has
skin that chronicles a
lifetime of
chronic sun exposure.
UV photography is not
necessary to see that
her skin is
dry, inelastic,
wrinkled, and heavily
mottled.
(Photos provided
courtesy of David H.
McDaniel, M.D.)
The best way to prevent Sun Damage
is to
avoid deliberate tanning,
including use of
indoor tanning
devices.Certainly it is important to
stay out of the sun
between 10:00 a.m. and 4:00
p.m., when the sun’s rays are
the strongest. Go
the the
Naval Observatory page and you
can calculate when in the year and
at what time the sun is greater than
a 50 degree angle for your location.
That is when you get the UVB rays.
Prevention
Antioxidant Products:
A number of products now carry
topical antioxidants which markedly
prevent the damaging effect of
free radicals produced by UVA and
Infrared IR-A radiation. They
also protect against the activation
of the MMP enzymes which damage
collagen. These are Vitamin
C, Vitamin E, Ferrulic Acid, Copper, Green Tea
and the newest kid on the block
Phloretin. These products
offer almost 100% "real time"
protection against the free radical
damage caused by UVA and IR-A radiation and
even prevent some of the burning and erythema.
Sunscreens and Sunblocks:
Sunscreens and sunblocks should be
worn year round and even on cloudy days as UVA still
penetrates almost 100%. Sunscreen should be
broad spectrum (offers UVA and UVB
protection) and have a Sun
Protection Factor (SPF) of 15 or
higher. Sunscreen should be
applied 20 minutes before going
outdoors to all skin that will
be exposed. It should be
reapplied after sweating or
being in water or every 2 hours.
It is important to
realize that the SPF of a Product applies only to the UVB
protection, not to the UVA protection. We recommend
the SkinCeutical Line of Sun Protection products.
These contain only Zinc and Titanium, no Chemicals.
Protective Clothing:
One method of protection we often
don't consider is the wearing of
protective clothing such as
wide-brimmed hat and long sleeves.
A number of companies offer lines of
sports wear and other clothing which
are designed to offer superior UV
protection. Umbrellas
and other items help to shield us
such as UV shields on our Car and
Home Windows. See
Several Links
Below.
Correction
The above products are effective
if used consistently and over a period of time and they
should be the cornerstone of your Skin Care Program. A
variety of light and laser procedures are beneficial and can
provide fairly however much more rapid resolution of some of
the many undesirable changes of photo aging. These
include Intense Pulsed Light, Home and Medical
Dermaroller and Diamond Microdermabrasion.
Our recommendation:
Use Skinceutical CE Ferrulic alternating with Phloretin CF
daily along with one of the SkinCeutical SPF 50 Sheer
Physical orPhysical Fusion Sunblock
Products.
A tanning bed or sunbed is
a device emitting ultraviolet radiation
(typically 95% UVA and 5% UVB, +/-3%) used
to produce a cosmetic tan. The lower
concentration of UVB lessens the chance of a
sunburn but there is considerable UVA
exposure which causes Melanoma and
Photoaging of the skin.
Promoting the health
benefits of UV rays is "like
recommending smoking to
reduce stress," said Dr. Len
Lichtenfeld, deputy
medical director of the
American Cancer Society.
The ozone layer shields the
Earth from harmful UV radiation. Ozone depletion, as well as
seasonal and weather variations, causes different amounts of
UV radiation to reach the Earth at any given time. The UV
Index is a daily forecast at noon of the UV radiation levels
people might experience. The Index predicts the next day's
levels on a 0 to 11+ scale, helping people determine
appropriate sun protection behaviors.
A UV Index reading of 11+ means
extreme risk of harm from unprotected
sun exposure. Minimize sun exposure
during midday hours, from 10 a.m. to 4
p.m. Apply sunscreen with an SPF of at
least 15 liberally every 2 hours:
8 to 10: Very High
A UV Index reading of 8 to 10 means
very high risk of harm from unprotected
sun exposure. Minimize sun exposure
during midday hours, from 10 a.m. to 4
p.m. Protect yourself by liberally
applying a sunscreen with an SPF of at
least 15. Wear protective clothing and
sunglasses to protect the eyes:
6 to 7: High
A UV Index reading of 6 to 7 means
high risk of harm from unprotected sun
exposure. Apply a sunscreen with a SPF
of at least 15. Wear a wide-brim hat and
sunglasses to protect your eyes:
3 to 5: Moderate
A UV Index reading of 3 to 5 means
moderate risk of harm from unprotected
sun exposure
2 or less: Low
A UV Index reading of 2 or less means
low danger from the sun's UV rays for
the average person:
The
eyes are affected mostly by the UVB rays, so wear a good
pair of sunglasses.
High intensities of
UVB light are hazardous to the eyes, and exposure can
cause welder's flash (photokeratitis or arc eye)
and may
lead to cataracts, pterygium, and pinguecula
formation.
Protective eyewear is
beneficial to those who are working with or those who
might be exposed to ultraviolet radiation, particularly
short wave UV. Given that light may reach the
eye from the sides, full coverage
eye protection is usually warranted if there is an
increased risk of exposure as in high altitude
mountaineering. Mountaineers are exposed to higher than
ordinary levels of UV radiation, both because there is
less atmospheric filtering and because of reflection
from snow and ice.
Ordinary eyeglasses
give some protection, and most plastic lenses give more
protection than glass lenses. Some plastic lens
materials, such as polycarbonate, block most UV. There
are protective treatments available for eyeglass lenses
that need it to give better protection. Most
intraocular lenses help to protect the retina by
absorbing UV radiation.
People should wear
sunglasses to protect
their eyes against ultraviolet rays
produced by sunlight in addition to
fashion
appeal.
Exposure to radiation from sunlight
has been associated with the
development of cataracts,
age-related macular degeneration and
cancer among other diseases. Few
people are aware that macular
degeneration is an incurable eye
disease and is the leading cause of
blindness for those aged 55 and
older in the United States.
For those who desire the added benefit of lenses
that reduce distracting glare, Life Extension’s new
OveRxCastsunglasses come
with polarizedgray lenses
that provide natural color definition with 100% UVprotection. Like the SolarShield®
sunglasses, OveRxCast polarizedsunglasses are designed to be worn over your
prescription eyeglasses.
This kind of clothing
usually blocks 98% of ALL UVA and UVB!!
is
the original sun protection clothing company in
Australia. The name STINGRAY is synonymous with sun
protection awareness and government education about the
sun's damaging ultraviolet rays caused by the harsh
Australian environment.
To Prevent Fading of Colors and too
much Heat in your Home and Car
Children ages 8–13 construct
UV Man! (or woman or dog!) and equip him with
special radiation detectors to investigate the
source of ultraviolet radiation in this 60
minute activity. They explore how we can protect
UV Man! — and ourselves! — from being exposed to
too much UV radiation.
All life on earth depends on the
light reaching us from the sun. Photosynthesis
harnesses the sun's light (remember
