Sunday, July 16, 2006

Physiology 101

Please don't take this post as coming from a physiology expert or from one who claims to have even the slightest idea of the totality of how the human body does what it does. The desire to post anything along these lines mostly comes from wanting to get down in writing the thougths and ideas that I have learned from reading various training books, web sites, and text books.

I've always been the kind of person to ask "why?" Before my first PIM training run, Pam stood up there and told us all that we should run easy...that we should be conversational when we run. I thougth to myself, "Why?" And ever since then, I've sought as much as possible to understand how the body adapts to training and how I might, as a new runner, maximize my workouts to get the most benefit for my time.

So, I'm not an expert. I'm not an exercise physiologist. I've not even had enough experience as a runner to give any personal perspective. I am certainly open to corrections, discussion, and even ridicule. This post and possibly some following represent my opinion and approach to training for new runners. I will attempt to answer (to my best understanding) the question, "Why?"

Last disclamer: This post could get way too long so I'm going to just go through the basics. If there is any interest or if I just get bored later, I may do some more detailed posts.

What is VO2max?
I think for me it is beneficial to start with the definition of VO2max. VO2max is the maximum volume of oxygen that can be used during complete, all-out exercise. At VO2max, your body does not have the capacity to take in and consume any more oxygen than it it at that intensity. Now, since oxygen consumption and energy expenditure are linearly related, VO2max is a meaure of an individuals maximum capacity to do work aerobically. Simple, huh?

So, what limits my capacity to do work aerobically? (btw, later we will get to what happens when we exceed our ability to do work aerobically. Be patient.) Well there are two things that limit my ability to do work aerobically or rather that limit VO2max. 1)The external delivery sytem's (heart and lungs) ability to provide the oxygen to the place where it can be used as energy (intake), and 2)The number of mitochondria in my muscle cells as well as the density of the capillary network surrounding that cell (uptake). This is the final destination of the oxygen and the site where it is converted into energy to be used for work (running in our case).

So, which is it? Which limiting factor to I target to get my body to work harder and longer aerobically? This is kind of controversial although to me it's a no-brainer. If you don't have enough capicity to receive the oxygen (the untrained athlete), it does no good to try to increase the amount of blood being delivered during each heartbeat (stroke volume). The untrained runner or new runner needs to concentrate on increasing mitochondrial counts and capillary density at the point of uptake. I'll get into how that is done later.

Man, this is getting to be a long post.

I'm going to need a little feedback here in order to continue. :) Is any of this worthwhile putting down on this blog. I know Cassie expressed a little interest when she asked " you have to keep your heart rate low? I need more explanation." If this stuff is of the least bit of interest to anyone out there, let me know an I'll continue.

To be continued (maybe)...

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