A Weighty Issue

I've talked to you a bit about VO2 max in the past.  I've told you that VO2 max is a good indicator of how well you will race for distances such as 2 miles or 5 kilometers.  Let me explain what VO2 max is:

Simply put, stands for the maximum amount of oxygen our hearts can deliver to our working muscles. Our bodies require oxygen in order to generate the energy that keeps us running down the road.  When we exceed our bodies' ability to supply oxygen to our working muscles, we fatigue very quickly.  We can then say that, the more oxygen we can deliver to our muscles, the less likely we are to become fatigued during a race.

So, what does a VO2 max number mean? I mean, how does a VO2 of 43 (what I currently have) compare to a VO2 of 69 (which I had when I was in my best shape ever).  The number, in VO2 stands for:

milliliters of oxygen per minute per kilogram of body weight

To concretely measure VO2 max, a physiologist would put me on a treadmill, stick a hose in my mouth to capture all of the air I breath out, start the treadmill and keep making it faster and steeper until I could no longer keep running.  The physiologist would then measure the air I breathed out, and determine how much oxygen I used per minute of work.  The physiologist would then divide the amount of oxygen I used per minute by my body weight in kilograms.  The number he came up with (43 for me currently), would mean that I used 43 milliliters of oxygen per minute for every kilogram of body weight.

You can estimate your VO2 max based on your current race times if you Use This VO2 max calculator.  A brief note, often the VO2 max predictor tables are referred to as "VDOT" tables.  I don't want to explain why right now, because it is not important for you at this time.

So, I plug my 2 mile time in from the July 4th race and the calculator tells me that my VO2 max is 43 milliliters of oxygen, per minute, per kilogram of body weight.

I currently weigh 81 kilograms, I've been eating and lifting a bit more during this summer, plus, I've noticed a little more than the usual pudge around my edges lately.  During the school year I was pretty consistently in the 78 kilogram range.  This raises the question, how much time, in a 2 mile race, does the extra 3 kilograms cost me?  I mean, it must cost me something, right?  If I were to strap on a pack with 3 kilos (about 6.6 pounds) on my back, I certainly couldn't run as fast as I could without the backpack.  So, how much do the extra 3 kilos cost me?

A little simple arithmetic can answer that question. This is how to do it

1. Find your current VDOT estimate using the above calculator
2. Multiply that number by your body weight in kilograms (a kilogram = 2.2 pounds).  This will give you the total amount of oxygen your body can use per minute.
3. Now, divide that number by the total weight in kilograms of a hypothetical lighter you (I can use my 78 kilos from before my trip to Iceland, for example.  This will give you a bigger VDOT number.
4. Plug that bigger VDOT back into the calculator and check your new, faster race times.

This is what it looks like for me.

1. VDOT = 43 ml of oxygen per minute per kilogram of body weight. (ml/kg/min)
2. 43 ml/kg/min x 81 kg = 3,483 ml of oxygen used per minute.
3. Divide 3,483 ml/min by 78 kg = 44.65 VDOT.
4. If I plug that number back into the calculator, I see that my 14:01 2 mile suddenly drops to 13:40.

I suddenly improved 21 seconds by shedding 3 kilograms.  I recently heard our #1 runner laughing about the belly he is developing this summer.  I'm looking at the results from this years section 3200m final and can see exactly what 21 seconds would do for him.

Next topic....How to shed the weight safely (if you have any to lose in the first place).

edit: This Link allows you to enter a VDOT number directly into the calculator to get your projected race times.