HR now lower for Z4 power, but higher for Z2

MishMash95

Hi,
With my training, I spend quite a lot more time focusing on the higher end zones, rather than doing a tonne of endurance rides. Mainly because I have been seeing improvements from those, and enjoy them a lot. I do mix in the weekend group rides, but given there are sprints, hills, pulls etc; only about 50% of the time is actually spent cycling at a consistent Zone 2.

What I've subsequently started to notice is that my heart rate when riding at zone 2 power has gone up. Previously, I was able to hold an avg HR of around 146bpm at 190w (over say a 3-hour ride). (My Zone 2 power at the time was rated at between 162-203w, with the Zone 2 HR estimated to be 120-161bpm). Around that same time, riding at a sustained 250w for 45+ min put me at 187bpm, whereas now, 250w sits me at 178-180bpm avg over similar durations, so my HR for the high end seems to have gone down, and I can definitely feel that the 250-270w range has gotten easier recently.

However, I can't seem to easily get my HR to stay low, having now to drop into Z1 power ( ~ 150w) to get it to drop to the low 140s. My question therefore is should this matter? and will there likely be a tangible benefit from focusing on getting the HR down at the low end? (I am still able to sustain the actual power numbers for the duration).

Note that this is going off of the estimated HR zones based on my max of 206bpm. I'll also throw in that even riding at a recovery pace of 100w, I can't seem to get my HR to consistently drop below 130bpm, which is still in Z2 HR according to the estimated zones.

robertpb

And how did you come to the 206bpm in the first place?
That's also a very big zone 2.

OnTheRopes

HR can vary, perhaps you are not recovered or if you are ill? Is this during a training ride, perhaps you are now working harder so tired, this will affect your HR in lower zones.
Do you use Golden Cheetah or other software? Try doing a 2 hour ride staying in Zone 2 and check your aerobic decoupling. Warm up properly then hit the lap button and ride in Zone 2 (lets say 200w) for 2 hours. Hit the lap button and warm down.
Your software should tell you the percentage of aerobic decoupling you have, if more than 5% then you are not aerobically fit.
You can do this for other aerobic zones such as tempo

OnTheRopes

robertpb wrote:

And how did you come to the 206bpm in the first place?
That's also a very big zone 2.

Zone 2 is quite big, at least according to Coggan 56-75% of FTP which makes my Z2 165 - 225

robertpb

OnTheRopes wrote:

robertpb wrote:

And how did you come to the 206bpm in the first place?
That's also a very big zone 2.

Zone 2 is quite big, at least according to Coggan 56-75% of FTP which makes my Z2 165 - 225

I think you are confusing the OP's watts and BPM

Midlands Grimpeur

My question therefore is should this matter? and will there likely be a tangible benefit from focusing on getting the HR down at the low end? (I am still able to sustain the actual power numbers for the duration).

It depends, what are you training for, if anything? If you were, for example, training for events that required good endurance such as a sportive then yes, being able to hold a higher output for a lower HR could be of benefit, potentially in helping you to ride faster for less physiological cost over a longer time period.

As you indicate you spend more time riding at higher power zones there is a chance that you have increased your anaerobic fitness at the expense of your aerobic fitness, hence the higher heart rate in lower zones. If part your goal is to get as fit as possible then maximising your aerobic fitness is the best place to start as this (usually) provides the base/platform on which all other power zones can be improved.

MishMash95

Cheers for the tips chaps!

206 bpm is my highest recorded HR, during a very intense maximal effort of 420w for 3 minutes, and yes, i've just been using whatever Strava uses, which I believe is the coggan 56-75%.

@OnTheRopeswill look into aerobic decoupling, had a quick google and that seems like an interesting measure! External factors could definitely play a part, as I'm 3 months into a new job and am probably not getting as much sleep as I want (not that there isn't time, I just wind up going to bed too late :P) and generally at the moment find myself riding harder on average. Given that I am feeling fitter in general, however, and with the zone 4 HR having gone down, I didn't know if this would be a factor at the low end.