"Re-heating", probably the last thing about callouses and heat

[Daniel W. Rouse Jr.]

My experiences so far show that "crosshatching", or making stroke lines on
the feet, does in fact cause callouses. The direction is always away from
the arch for horizontal lines, and away from the heel for vertical lines and
both diagonals. Callous maintenance is just diagonals only, without any
horizontal or vertical strokes. Devices used matters: I started out with
smallish shallow scrapes with the end of a toenail clipper, moved to a
grillstone type of pumice, and then to a cheese grater type file. As the
calloused skin got tougher, the stoke pressure had to be firmer. But, even
though crosshatching does build up the callouses, it also does indeed scrape
away a small layer of existing tough skin and therefore callous--so already
there had to be some caution not gouge too deeply into existing calloused
skin, especially making sure not to cut toe pads. That also means a small
amount of roughness training needs to be redone, and a small amount of heat
training needs to be redone each time--not overdoing it, but still making
them long enough to expose the new callouses to roughness and heat without
getting blisters. I find it's okay for the small amount of heat re-training
while still doing crosshatching to result in red soles that may even feel
stinging for several minutes afterward. No more than that, since additional
crosshatching will be done within a few days.

Then at some point, when the crosshatch lines show up as visible black lines
even with mostly clean feet, and when entire white callous spots appear even
on mostly clean feet, then it is indeed time to stop crosshatching and start
retraining the feet in their current condition. In my experience, one thing
is certain: the gradual buildup of callouses from previous crosshatching
does already make it easier to walk longer on rougher surfaces, such as
gravel asphalt, but particularly pointy gravel still feels sharp enough even
if not necessarily too painful. For heat, there is more than a trivial
amount of heat lost that needs to be regained with longer and deliberate
standing and walking on hotter heat--so I'll call that longer phase as
"re-heating" the feet.

Now, when I started re-heating the feet today: I found that heat tolerance
dropped all the way to a maximum tolerance of mid 80's air temperature and
2:30pm into the afternoon peak heat hours. But, it still did allow for
several seconds of standing before it got beyond just painfully hot--and I
took it just to the point of wincing and closing my eyes because it was in
the mid 80's and not too much heat too build up too fast. Upon resuming
walking after that much burning, I found that a slight twinge of a foot
tingle occurred as the foot accumulated just that much more heat, before it
started dissipating from walking--but not enough to blister from that twinge
of tingling. I also found I was able to walk several tens of steps before it
started to become noticeably burning hot once again, at which time I stood
once again until it just got too hot. This cycle of standing and burning
until it got painfully hot, the twinge of a foot tingle just at the start of
walking, and then stopping again once it got noticeably burning
hot--deliberately lasted for about 10 minutes, with only a couple times of
momentarily going to sidewalk when the feet did not cool down enough and
continued to build up more heat while walking, but not once ever needing
shade. There's no other way to go about it, gradual heat acclimation is the
only way any barefooter is going to get used to the heat, and I can't find
any other way. Blacktop asphalt is the most effective for this, given it's
very smooth so there are no air gaps at all (vs. gravel asphalt that may
still have small air gaps in between the rocks).

So, from this point and beyond, it's just toughening by progressive burning
until the heat is just too unbearable for the air temperature and time of
day, and little to no extra heat tolerance is being made. Examples of last
year's limits were blacktop asphalt at 98 degrees and 1:30pm, and even with
sidewalk only it was 100 degrees and 2:30pm, but then I also wasn't using
crosshatching to build callouses faster either. So, once that limit is
established--then it's a balance of starting out earlier before it gets that
hot, or starting out later after it's cooled down from that hot, or else
having to wear flip flops during that much afternoon peak heat (but still
taking them off every so often and trying even small amounts of that much
heat, before putting them on again). I also do find that the callouses from
crosshatching are still surface rough at this time--if I run them across a
smooth cloth, such as a bed comforter, not only will it feel like the soles
are kind of like gritty sandpaper running across the cloth, but there will
actually be a soft abrasive sound heard as if sandpaper is being run across
the cloth. This is definitely the case for the toe pads, the balls of the
feet, and the edges of the feet, but the heels barely do that at all.
Whether or not these smooth out to leathery or remain rougher will likely be
later--but I generally do more hot surface walking than I do rough surface
walking so they may become smoother.

Beyond that? Well, that's all I can think of as any additional useful
experiences and information about building up callouses faster and still
working roughness and heat tolerance. This isn't new, except for maybe the
crosshatching since I can't find any other references to it, but everything
else is what every barefooter goes through for rough surfaces and even
moreso in summer for heat. How much overall progress depends on the goal of
the length of the walk and the heat of the surface.

I've also confirmed that surface dirt is able to be cleaned off with two or
three handwipes per foot. Surface dirt only, because heat baked ingrained
"permadirt" might still remain--especially on the toe pads, the heel, and
also around any edges of any craters due to healing blisters.