Power meters.

ajmitchell

sagalout wrote:

I don't know if thats the proper term, but if I ride at, say 155bpm on the turbo for an hour (threshold pace for me) If I check my power output it will start to trail off slightly for the same HR.

If I ride by power at say 250W for an hour, my heart rate edges up over time. I think its to do with the extra heat generated when riding indoors, but basically training by power eliminates it, as you can ignore the HR and make sure you're actually keeping up the proper effort for the full duration.

sorry to cut to the chase but its called getting fatigued. No one can hold the same power at a fixed high HR indefinately and no can hold the same HR at a fixed high power. Either power drifts down or HR (effort rises). However, I appreciate you taking time to give me your observation.

Tom Dean

ajmitchell wrote:

sorry to cut to the chase but its called getting fatigued. No one can hold the same power at a fixed high HR indefinately and no can hold the same HR at a fixed high power. Either power drifts down or HR (effort rises). However, I appreciate you taking time to give me your observation.

No, its called HR drift. One of the reasons not to equate HR with 'effort'.

Team4Luke

Tom Dean wrote:

ajmitchell wrote:

sorry to cut to the chase but its called getting fatigued. No one can hold the same power at a fixed high HR indefinately and no can hold the same HR at a fixed high power. Either power drifts down or HR (effort rises). However, I appreciate you taking time to give me your observation.

No, its called HR drift. One of the reasons not to equate HR with 'effort'.

HR drift is often banded around, massively overrated, the above is fatigue, the human body is not a robot, it must always respond to the stress it is under, HR is merely a dial like in your car. You can only really put drift down to things like heat build up or taken in something to effect it, high dose of caffeine perhaps to give unreliable readings to your own perceived effort, extreme tiredness, overtraining. Otherwise we could all choose whatever power we wish to hold and all do 49 min 25's.

mattshrops

I think the point thats being made is that using power you can apply a constant effort. If you use hr you cant-even using rpe will change on how you feel day to day.

So fairly obviously one is a more accurate training tool than the other. Whether that justifies the expense is a matter for each person to decide.

Tom Dean

Team4Luke, not quite sure what you are trying to argue.

HR / cardiac drift seems fairly well defined to me. If you want to explain it with a vague term like 'fatigue', fine. A quick google suggests other, more detailed explanations have been found.

Anyway, way off topic. Apologies.

sagalout

For me it's heat related as I only get it on the turbo (I don't have a fan)

In an actual 25 mile TT my heart rate is constant for the power, but on the turbo it creeps up as the session goes on.

Eyorerox

Read this, I think this was what NapD was referring to
http://www.bikeradar.com/blog/article/t ... als-32678/

ajmitchell

sagalout wrote:

In an actual 25 mile TT my heart rate is constant for the power, but on the turbo it creeps up as the session goes on.

would you mind sharing a link to the power file as I'd be fascinated to see. The only way HR could be constant is if you warmed up very extensively to reach near max HR and then rode well within your FTP. Anything else will see significant "strain" towards the end of the race.

napoleond

People are getting confused here. Cardiac drift occurs as the body responds to effort. For any given effort, HR increases over time. If you go on HR you will stop pedalling as hard. My sweet spot training at a given wattage may start at 145bpm and end at 172. If I did it all at 165 I'd start too hard and finish with not enough.

WRT the HR on a TT staying the same for a given power, I get the same! Most odd. I'll see if I can dig out a file.

moonshine

here is an example of HR drift on the turbo...
30 min @ 271w - red is power, blue is HR. 140bpm @2min, 156bpm@15 min, finishing at 166bpm @ 30 min.

moonshine

ajmitchell wrote:

......The only way HR could be constant is if you warmed up very extensively to reach near max HR and then rode well within your FTP. Anything else will see significant "strain" towards the end of the race.

+1
this is an example from my first 10 of the year, showing the Max HR being approached at the end of the race
It takes 4 min to get into the swing of things and HR gets to 172 @4/5 min. my out leg into a slight headwind was was 299w AP, and the return leg was 282w AP.
HR increaced gradually from 172@4 min to 183bpm @ end of race at 22:32.

golfergmc

Finally getting mine on Monday but can`t use it for a while because I was a tw@t and fell off my mtb today and knackered my knee,gutted!!!.