I saw the same information in the July 1998 issue of Vegetarian Times.
Its news page cited a "study out of the University of Indiana in
Bloomington".  It stated that the level of antibodies in breastmilk fell
by almost 50 percent immediately following a vigorous workout.  The Veg
Times blurb went on to say, "But don't worry, the post-exercise plunge
isn't permanent.  Levels shot back up to normal within an hour after
activity.  Simply waiting an hour to breastfeed eliminates any risk that
your baby won't get all the nutrients he/she needs.  This is truly one
of those cases where timing really is everything."  I read this w/ mixed
feelings...at least it didn't suggest pumping and dumping like Runner's
World, but I've never had the luxury of enjoying a vigorous workout
*plus* an hour following it before a baby wanted something to eat!
(With successive children, my definition of vigorous has been redefined
since that vaguely-remembered time before kids...in fact, does being 7
mos pregnant and hauling one child while vacuuming the stairs count as
vigorous...or just dangerous?) :-)

Has anyone seen the actual study from Indiana-Bloomington?  Even if a
mom enjoys such a workout daily, it seems as if the exercise would just
affect that one time at the breast w/ 50 percent fewer antibodies in
that amount of milk.  Is this such a big deal that I need to listen to
my little one scream for an hour so that he gets a few more antibodies?
Having spent a great deal of time around moms w/ "exercise-bulimia"
where excessive calories was the purge mechanism, information presented
like it was in Runner's World may only encourage those same moms to do
more bottling w/ ABM.  (Sorry I don't have an address for the Veg Times
since a friend clipped the blurb for me.)

Rebecca DeYoung Daniels, MBA, RD, LD
Overland Park, KS (Kansas City area)