IPPT Update with aching knees…
Congratulations my dear boy. You have successfully ran a gold timing during your self-timed trial just now at the expense of your poor, overworked and overstrained legs. Have you not learnt from the years of distance running and pushing that you’ll probably need an inevitable operation if you continue to seek that dastard 400 monetary reward. Do you want to relive that one year of annoying limp back in the army? Bah, I’ve warned you a million times already but you don’t listen. Fine go ahead and abuse your poor body. I’m just your conscience and the physical have no meaning to me.
- With a grudge, your conscience
Fine so I couldn’t walk well after my run just now. But it seems that $400 is not as elusive as it seems anymore. My 2.4 timing has improved from a 10:03 a week ago, to 9:57, 9:43 and now 9:35. If this keeps up, gold is mine to keep the coming Monday. Its a good sign as well, with my end heart rate falling, from 186 to 160 now. Which means my aerobic fitness is improving. But yes at the expense of my knee… Still, i’m duely concerned about my 3rd and 4th lap, which seems to retard my entire 2.4 time and seemingly attempts to supplant my quest for gold.
Anyway, the geek is back. Today we shall talk about Cardiovascular drift.
As we all know and have probably realised, when we exercise, our heart rate goes up. This is to provide our oxygen deprived (or hypoxic) cells enough oxygen flow to keep up with the increased demand. Hence, to some extent, heart rate can be used as a good measure of the aerobic level of our current exercise in relation to our fitness.
Let’s say X is 20 years old. His age predicted maximum heart rate is 220-20=200. When he does weight training, he sees his heart rate increase to 120. This means the aerobic intensity of his work out is approximately 60% of his aerobic capacity. When he runs, he’ll probably see his heart rate hit 160. This means the aerobic intensity of his run is approximately 80% of his aerobic capacity.
Note these are not DEFINITIVE parameters, but more of a guide to see how you are performing. There is no one single parameter to determine aerobic output, but a host of factors, such as oxygen consumption (VO2), heart rate, Ventilatory Equivalent Ratio (Ve/VO2), blood lactate concentration etc… Heart rate happens to be the easiest to measure for the common masses.
But do you notice something? Let’s say X runs at a certain speed. His heart rate for the first 3 minutes was an average of 160. After 10 minutes, he realise his heart rate has increased to 170, and as the run progresses, his heart rate rises even further! Have you ever wondered why? This phenomenon is called Cardiovascular Drift. See, your body requires approximately the same amount of oxygen to maintain the same speed, so the CARDIAC OUTPUT has to be maintained. Cardiac output is determined by stroke volume (how much your heart can pump in a beat) and heart rate.
As you exercise, you sweat and you lose water, deceasing your blood volume. Hence stroke volume decreases. In order to maintain the same amount of output, the heart has to beat faster. And that’s one of the reasons why our heart rate continues to increase despite us maintaining the same pace when we run.
SO much for being geeky.
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