During my shower this a.m. I had my back to the spray and noticed how much
warm water was flowing over my non-lactating breasts.  :-)
Time to talk to the physical therapist at work.  Called her and asked her
about heat vs. cold.  Her comments were very interesting and those of you
with access to a PT may want to check out what their current therapies are
for swelling.
        Her big comment was comfort vs. physiology of the tissues.  She felt
comfort was much more important because of let down, and she assured me
that warmth would not damage the tissues (I asked specifically here)
because you were doing something -- moving milk out.  She agreed cold or
warmth was okay -- whatever the mom felt the most comfort from.
        She said when you apply cold and take it off, you have a shift to warmth.
When you apply warmth and take it off, then you have a shift to cold.
        Contrast baths are used for "chronic" injuries (heat 4 min., cold 2 min.
-- heat is used twice as long as cold).  Acute injuries usually use cold to
prevent FURTHER swelling.  She did not see engorgement as acute or as an
injury (realize she was probably talking about less severe cases, or sees
as part of life as she did not have the 10 steps to successful
breastfeeding on her side).  She also said heat "makes more room" with
dilation and you are removing the pressure by removing the milk.  She
definitely sees the breast as different from an ankle!!!
        Most fun was when she got into physics (which I never took so I could be
way off here, but I did repeat back what she said to me):  in the light
spectrum there is infra red which is a low band, and ultraviolet which is a
high band.  It is a spectrum of energy.  Cold and heat are very much alike
on the spectrum -- and closest to the low band.  She said in the bigger
picture, there was not that big of a difference between heat/cold.
        Although I am "physic-less", I do find it interesting that in so many
posts, everyone is really right in 1 way or another.  Even with a physical
therapist, the issues of heat vs. cold are not cut and dried completely.
Jill Lund, RD, MS, St. Louis, Missouri, USA, WIC
Loving Support Makes Breastfeeding Work
p.s. our PT is going to try to look for some documentation, 1983 graduate
so she was alive anyway in 1966 (smile!)