Mr. Curious,
As an engineer, what you don't seem to understand that the pump we are talking about is a biological pump, so the efficiency of that pump can vary depending upon the conditions it encounters. Human biological systems have evolved to operate mnost efficiently at a pH of 7.4 with certain optimum concentrations of necessary chemicals (and these optimum concentrations are different both inside and outside the cell). In general, muscle contraction is reduced if any of these optimum parameters is outside of the optimum range. It is why peopole drink water and take electrolytes and glucose and everything else they do to improve performance while competing. Unfortunately, close to VO2 max, the changes are so profound that there is nothing that can be done, at least in my view.
What the cardiac limitation people are saying is the heart is immune to this millieu effect. It doesn't matter to them if the periphery is pumping out acid changing both the pH and the concentration of potassium and all sorts of other things from this optimum range, that as long as the pumping effect of the heart is noticeably less, the heart must be the limiting factor. It is an undergraduate understanding of the system. They spout it because they believe it not because they have evidence to support it, but because that is what they were taught. I am simply trying to get them to give me a good medical (biochemical/physiological) basis to explain the the findings. It is what I was taught (or, AC says it) so it must be right is not sufficient to me. It is very uncomfortable to have ones feet held to the fire.
Frank
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Frank,
An original Ironman and the Inventor of PowerCranks
As an engineer, what you don't seem to understand that the pump we are talking about is a biological pump, so the efficiency of that pump can vary depending upon the conditions it encounters. Human biological systems have evolved to operate mnost efficiently at a pH of 7.4 with certain optimum concentrations of necessary chemicals (and these optimum concentrations are different both inside and outside the cell). In general, muscle contraction is reduced if any of these optimum parameters is outside of the optimum range. It is why peopole drink water and take electrolytes and glucose and everything else they do to improve performance while competing. Unfortunately, close to VO2 max, the changes are so profound that there is nothing that can be done, at least in my view.
What the cardiac limitation people are saying is the heart is immune to this millieu effect. It doesn't matter to them if the periphery is pumping out acid changing both the pH and the concentration of potassium and all sorts of other things from this optimum range, that as long as the pumping effect of the heart is noticeably less, the heart must be the limiting factor. It is an undergraduate understanding of the system. They spout it because they believe it not because they have evidence to support it, but because that is what they were taught. I am simply trying to get them to give me a good medical (biochemical/physiological) basis to explain the the findings. It is what I was taught (or, AC says it) so it must be right is not sufficient to me. It is very uncomfortable to have ones feet held to the fire.
Frank
--------------
Frank,
An original Ironman and the Inventor of PowerCranks