Cardiac Drifting
Now - there's a lot of noise in there, variations as I went up or down slopes, stopped to cross a road, or take a drink occasionally, but basically, there's a trend. The red line at the top has a definite upwards trend, whereas the blue line at the bottom stays roughly horizontal. i.e. Heart Rate is going up while the pace stays roughly level (going down if anything, if you look at the figures in the previous blog entry).
This is a phenomenon known as cardiac drift. Now - I've heard various theories, but there is a school of thought that you can train to get rid of this. Some say the best way is to train hard, and then your body gets more used to a pace, so if you back off your fastest pace by a bit then you can run comfortably without cardiac drift. Others say that the trick is to train your aerobic capacity (the bit that does the work before you start working hard), and that this is a much neglected thing. However, top triathletes do train this, and get used to burning fat etc and building what they can do at a low Heart Rate. It's called Base Training, and is something I'd tried before and it had pi55ed me off big time as it was sooooo slow!
However - for some reason (partly after re-reading Windsurfin' Susie's article), I decided to give it another crack. And here are the results:
A shockingly slow pace, but the trends are roughly level (although the figures do still show a weeny bit of drift - see below). In my defence a lot of the last mile has an uphill slow (and equally, the first mile has a downhill slope as it's an out and back course - the Nonsuch one I've been using a lot recently.
Interestingly, I measured my Resting Heart Rate today, and it was 52. The max HR I've observed is 207, so that give me 155 inbetween. Using the Karvonnen wotsit (please check WUmbly) this gives 70% wotist (RHR + 0.7 x (MHR - RHR)) as 52 + 0.7 x 155 = 160, and 60% as 144bpm. So today I was running below 60%. Not sure if this is good or not - it should certainly burn fat. I want to get rid of the cardiac drift, so I think it has to be done, however low the percentage!
posted by XFR Bear @ 9:15 am
3 Comments:
all very pretty mate but they also say that fat burning at a low HR is bollox! Too many theories! Everyone has their own ideas!
anyway good to run and can you stick to mph not kmph!
Never heard it said that it was bollox, just the idea that it's *only* burnt at low HR's was bollox. As I understand it the percentage of energy that comes from fat drops, but there'll be some burnt still at a higher HR.
Bliddy hell Pix - you're ten years younger than me - if I can deal with kilometres then so can you :-P
Of course, perhaps your max hr isn't so high now (lack of fitness)? This would change the calculations. For example, max hr of 190 would give 60% at 135bpm, so 137 average would be just over 60%. I'll go away and think about the best way to train against cardiac drift......
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