[pct-l] Damnable Blisters

[CHUCK CHELIN]

Good morning, all,

I don’t get many blisters if I walk sufficient to keep my feet tough, but
when booking miles after a lazy season it’s possible something will pop up –
literally and figuratively. When I hike far-and-away the most troublesome
location is at the balls of the feet, behind the second toe.  That ball area
is the most forward part of the foot excluding the toes, and thus bears the
brunt of applied force when one pushes forward in a stride.



Blisters form when the outer thickness of skin is slid parallel, i.e.
sheared, sufficient to cause it to become separated from the under-layers of
skin.  Once the two layers are no longer connected fluid leaks into the
fissure and a prominent blister is formed.  This usually happens in a very
local area -- maybe a half-inch in diameter – but if not promptly attended
it will soon become much larger.  A continued application of force to the
area causes the fluid in the blister to act exactly like hydraulic fluid:  When
foot force is applied the fluid pushes every direction with equal pressure.
That means that the pressure of the fluid acts sideways to force more skin
apart making the blister grow into a much larger area.  It even grows into
areas where there is no direct force applied by the foot.  This separation
will continue until the outer skin layer rips and forms a rather nasty
wound.



Preventing blisters is primarily an engineering problem, while repairing
blisters is primarily a medical problem.  My preferred prevention solutions
are, in order of desirability:  conditioning, force management, friction
reduction, and friction mitigation.



*Conditioning:*  The most effective preventative action is to do lots of
training to toughen the feet.  I always have plenty of warning that the ball
is becoming distressed when I begin to feel a tender burning long before
real damage occurs.  I like to hike until I “feel the burn” -- then stop for
the day.   Over time, and with increasing miles, the skin layers adapt to
shear loads and the burning no longer occurs.



*Force Reduction:* Assuming our feet can’t always be as thoroughly
conditioned as we’d like, and assuming that we’ve already reduced ourselves
and our loads to ultra-lite status, we can next reduce the problem by
managing how the step force is applied to the skin of the foot.  I find that
sneakers are able to flex slightly to help spread the load over a wider area
of the foot, and thus reduce the specific force at troublesome
locations.  Additionally,
most sneakers have EVA foam mid-sole construction which is somewhat
“squishy” to more widely distribute and reduce the load. Early in the hiking
season I also add some additional “squish” by using thin SPENCO foam-rubber
insoles.  Since they add weight to the shoe I remove them after a few weeks
when my feet have toughened.



*Friction Reduction:*  Applied force alone won’t cause a blister; it is
necessary to shear the skin sideways during the application of the force.  For
any given force, the greater the friction the greater the potential for
creating a blister.  Some people claim that blisters form due to heat, or
the accumulation of moisture – possibly as a result of heat.  Both are
contributing factors only to the extent that they increase the friction.  Heat
may cause perspiration dampness, and the dampness does two
less-than-desirable things: It softens the skin making it more susceptible
to shear failure, and it increases the friction between the skin and the
sock fabric.



To reduce the accumulation of moisture it is helpful to wear shoes that
ventilate well to encourage the moisture to escape.  On the desert sections,
one accomplished and experienced hiker said if she couldn’t feel the breeze
through the shoes her feet weren’t ventilating well enough.  It is also wise
to change one’s socks regularly; allowing the socks to dry even if they
can’t be washed.  Washing is very useful because while sweat will air-dry,
there will be an accumulation of salt remaining in the fabric.  Salt has a
great affinity for moisture, and if the salt remains even the most
‘breathable” sock fabric will always feel “clammy”.  Regardless of what your
Mommy said, it’s not even necessary to thoroughly wash the socks with soap.
A good rinse in plain water is excellent at removing the residual salt, even
though oils and dirt may not have been thoroughly removed.  Foot powders are
also good at absorbing moisture, but periodic sock rinsing is necessary to
remove the accumulated powder crud.



Various “slick-um” substances are good at reducing friction, and I’ve tried
many of them.  One of the best – but least desirable, in my view – is
petroleum jelly lubricant.  I’ve used to use it when running miles and miles
on a hot day, but it makes an awful mess that I don’t want to deal with on a
long hike.  When wearing shoes that ventilate well, dust/dirt accumulation
is a fact of life.  If a lubricant can hold dust the result will be an
accumulation of abrasive goo in both shoes and socks that can’t be readily
removed.



*Friction Mitigation:*  We can’t entirely eliminate friction so we must find
a way to mitigate the effect it has on the skin layers.  Tape is great at
reducing friction, but tape’s greatest value is the way it can mitigate the
effect of whatever friction there may be.  Properly applied tape will spread
the sideways sliding tendency of the skin to a much broader area thereby
reducing the likelihood of skin becoming separated to form a blister, or
similarly, prevent an existing blister from becoming worse.  I’ve used quite
a number of different types of tape – but not all – and most work OK; just
find something you like, preferably something with a slick outer surface.  Duct
tape is OK – and it seems to be “trail chic” - but it does not comply well
to compound curved surfaces so it forms little folds and seams that can
eventually cause mischief.



I prefer the standard-thickness MoleSkin.  Many hikers don’t like it,
claiming it won’t stay in place, but properly applied I find it will not
only stay stuck, but it will stay for several days.  I like the flexibility
of MoleSkin, and they way it can conform to the compound curved surfaces of
the foot.  It’s important to size the patch to be as large as practical to
widely spread the shear load, and to design the patch to have somewhat
rounded corners, and to have its edges in low-contact areas as much as
possible.  It’s also important to clean and dry the foot as well as possible
under the circumstances.   I prefer to use alcohol for cleaning because it
removes oils and it has a great affinity for water.  If the blister has
opened the application of alcohol can be quite distracting for several
minutes, or until you’ve climbed down out of the tree you jumped into –
another good reason to address a hot-spot before the skin has broken.



If there is just a hot-spot I apply the tape directly over the skin.  If the
skin has become loose due to a blister I clean the area then apply a small
wipe of some kind of lubricant only to the loosened skin.  Anything that
prevents the tape adhesive from adhering is good. Often I use ChapStick for
that purpose.



Once a blister has formed I drain it and keep it drained.  Sometimes the
skin will heal back in place, but most times the damage is done and
eventually the inner skin will toughen while the outer skin loosens and can
be snipped off.  Some hikers advocate using the old method of poking a
thread through the blister with a needle.  The theory is the thread will
keep the drain holes open and will wick the fluid out of the blister.  I’ve
tried it -- it didn’t seem to make anything worse -- but I don’t believe
it’s worth the trouble and the risk of infection.  Your results may vary.



I agree with Piper that an unrelenting, flat, smooth surface is tough on the
feet.  The PCT is certainly not as bad as pavement, but does encourage
repetitive stress syndrome.  When the same parts of the feet are loaded in
the same way for hours, days, weeks, and months at a time those limited
areas can become distressed.  Flexible shoes, that can move on the feet when
walking on less-than-flat surfaces, will spread the load around and fewer
foot problems will result



Steel-Eye

Hiking the Pct since before it was the PCT – 1965

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