After posting the discussion re anaerobic thresholds, etc.,
I received a number of questions, primarily regarding why
the anaerobic threshold is supposed to be "set" at 158 bpm.
I re-checked my source and found the number 158 was based on
a study doneby Persson, et al in 1974, which observed that
when lactic acid levels reached a concentration of 4 mmol/L,
(which is considered by equine exercise physiologists to be
the "anaerobic threshold"), the heart rate was consistently
between 150-160 bpm. (Don't ask me why the textbook then said
specifically 158, I just passed on what I'd read). So, let
me revise my earlier statement of 158 to 150-160 bpm.
However, there have been questions and discussion as to why
this is a fixed number (or range). Before I answer those questions,
I'd like to dig out the original research article, plus rummage
around in the research databases and see if any other work has
been done to either support or contradict the original work.
This may take me a few days, but as soon as I find out any
thing more, I will post it. 'Kay?
In the For What It's Worth department, I'm working on an
article discussing and explaining some of the basics and
even the not-so-basics of aerobic/anaerobic pathways,
lactates, factors that affect it, etc. I know, alot
of you veterans already know this stuff, but maybe alot
of newer people don't quite have it yet, and that's why
we're all here, right? Hopefully I'll have it finished
fairly soon and submitted for publication (maybe Endurance
News.) All the good questions and intelligent discussion
received so far has really helped me figure out what areas I
need to discuss and/or explain better, what examples work
and which don't and to make sure I double-check my
references <BG>! Anyway, while I'm writing this article,
any suggestions, comments or questions would be
VERY GREATLY APPRECIATED. Obviously, if I'm going to go to the
trouble of writing it, I'd like to make sure it does everyone
some good and provides some usable information. Thanks!
Susan Evans also Cato, Katy, Lady and Dakota the Terrible (aka Spudnuts)
Equine Research Center
California State Polytechnic University, Pomona