HR increases

acoggan

While I can't think of any studies off-hand, in a general sense you would expect that greater cardiovascular fitness would be associated with an attenuation of cardiac drift. The big leap-of-faith, though, is in claiming that attenuation of cardiac drift to X degree under Y conditions represents some sort of benchmark that you can use to assess when your "aerobic development" is "complete". That I just can't see....

In any case, the SRM software has for years included a far more sophisticated tool for graphically assessing cardiovascular fitness/cardiac drift, but while I find the basis for it easy to understand and logical, dang if I've ever found any real use for it!

acoggan

Good point! To add to it: a few years ago I had a ~6 mo streak during which I rode at least 4 h on one weekend day. My heart rate response to exercise was clearly suppressed, i.e., at a given submaximal power my heart rate was lower than usual, and it didn't increase as quickly at the onset of a workout. I don't know about the more long-term drift, though...guess I should go back and take a look. In any case, however, what's relevant here is that my ability to generate power for various durations (including during such long rides) wasn't any better than when I'm not doing such mega-miles (well, for me, anyway), even though the latter impacts my heart rate. I'd therefore hypothesize that an excessively "flattened" heart rate response may actually be a bad thing, as it may be a sign of longer-term overreaching/overtraining (of the parasympathetic variety).

Steve_B

I know very little about exercise physiology and I could never figure out what to do with that feature in the SRM software either. It is in some way comforting to hear someone like you saying the same thing, Andy.

Daniel Thomas

Thank you for some really good responses. Frenchyge, sorry for not answering about cadence, we both always use the same cadence too (about 91-93rpm).

Maybe friel was a red-herring in this thread altogether - I'm not really bothered about quantifying anything, but if people dismiss him I kinda would like to know why and youve explained that now.

I suppose I'm just interested in what causes cardiac drift, given that my mate doesn't have any and I do. I'll leave you all in peace now and go and look elsewhere. Thanks.

acoggan

That's good...I guess?

Seriously, the real problem is that the analysis can only be applied to individual files, which simply don't provide enough data to overcome the variability in the heart rate-power relationship, at least when cycling outdoors. It would be more useful if you could fit the regression to all the data from a batch of files simultaneously, or if you could just keep track of the slope, intercept, PWC150, 'shifting', from individual files in a database (e.g., in the SRM software's equivalent to WKO+'s Calendar View). The latter could be accomplished by entering the derived values into, e.g., a spreadsheet, but I've never gone to the trouble because I don't think I'd learn anything of value.

peterpen

Which tool is this? I typically only use SRMwin for downloading & marking intervals, but as one of the heretics who pays (limited) attention to HR, I'd be curious to check it out.

acoggan

It's the one they simply call "SRM Analysis", which you can perform by clicking on the little icon on the toolbar that shows multi-colored diagonal lines. What is does is:

1) smooths the heart rate and power data using a rolling average the duration of which is specified via the "Analysis" tab of the "Options" pop-up;

2) performs a linear regression of smoothed heart rate vs. smoothed power, while time-shifting the data (to reflect the delay in the change in heart rate following a change in power output) to maximize the R^2 value. This generates a slope and intercept ("zero position") of the heart rate-power relationship, which is then used to predict the power that one could produce at a fixed heart rate of 150 beats/min (PWC150). The optimal "shifting" value is also given.

3) plots the smoothed heart rate vs. the smoothed power, using one of six different colors to represent the different sextiles of the ride (e.g., the 1st 10 min of a 1 h ride is plotted in yellow, the 2nd in red, etc...the ordering is shown by the little multi-colored bar found in the upper right hand corner of the screen).

Applied to the analysis of multiple rides, what you'd expect to find as your cardiovascular fitness improves would be a reduction in the slope and/or intercept of the regression line, resulting in an increase in the PWC150 value. In addition, the time-shift should decrease (although the magnitude of the expected improvement is quite small, and as such, easily overlooked when analyzing data collected in the field instead of a laboratory). Finally, you'd also expect to see less cardiovascular drift, such that the squiggly multi-colored line would remain closer to the regression line, versus the pink or blue parts being above and the yellow or red parts below.

Now for the ironic part: to refresh my memory re. all the details above, I called up one of my wife's recent workouts, which consisted of riding an ergometer at a fixed power of 200 W in our <65 deg F basement with a fan moving air over her at ~5 m/s. Regardless of whether I use the SRM Analysis tool or Friel's approach as implemented in the soon-to-be-released version 2.2 of WKO+, the amount of cardiovascular drift she experienced is minimal (e.g., <4% change in heart rate-power from 1st half to 2nd half of workout, which is how Friel suggests quantifying the amount of cardiovascular drift). Why is this ironic? Because she's been running, not riding, for the last ~2.5 mo, and as a result her cycling fitness has declined considerably...

peterpen

Thanks for the detailed explanation, Andy - very much appreciated.

Porkyboy

FWIW I agree with your analysis. I think this sort of picture appears not just when one has gone as far as P/S overtraining but when one starts to suffer from what I understand to be called central fatigue, as per the Oxford Textbook of Sports Medicine, amogst other sources. My understanding of this phenomenon is that whilst the muscles etc. may well have recovered and the CHO stores may well have been replenished "normal" power cannot be produced because of an inability of the CNS to provide the appropriate and required neurological stimulus because of "central" (CNS) or neurological fatigue.

That's my belief and understanding anyway, neurological fatigue is IMHO often forgotten but it's utterly fundamental, without proper neurological recovery and therefore function, put simply noting else works properly. Hence my strong interest in daily HRV measurements, it provides a window to look into the autonomic nervous system and it's condition.

I'll go back to sleep now!

PB

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Porkyboy

Hi

I agree. Check out this link, these HR curves were produced over about a month and were during workouts on a callibrated CompuTrainer all at a fixed identical load. I cut one of them short simply because I felt too fatigued. The variations here are caused simply by different fatigue/recovery states related to other training and I am wholly unconvinced that drift is likely to ever be more than a bit of a personal guide to recovery status and never a decent measure of overall training status or a tool to compare athletes. Too many variables.

PB

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Steve_B

That's what I was thinking. I'd always look at the PWC150 number and immediately think that I should compare to other similar rides to see if there is a trend and then I'd think, "why isn't the software allowing me to do this easily or doing this for me instead?"

frenchyge

More detail on Friel's HR : Pwr analysis here http://www.cyclingpeakssoftware.com.../decoupling.asp

Has anyone used that feature in WKO+? Is it only in a newer build? I don't think I've ever noticed that 'coupling' data field before.

rmur17

aye it's the latest build and a good reason not to upgrade ...

I guess it's just me but after six years of training with power ... adding HR as a serious piece of the mix seems like a step backwards.

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frenchyge

Aw... you're just sour because after 6 years you're still underdeveloped. Less talkie - more ridie.


Edit: Wait. It's a FREE* update! ...and it looks like it has some other decent stuff besides the HR : Pwr metric. Did Hunter not announce this, or did I miss the announcement in the spam?


* for existing WKO+ 2.x users.