Why is my HR mostly in Z4 and Z5 during C category races despite me having 3.2W/kg?

Hello everyone,

I am pretty new to Zwift, have around 450km done so far. My main question is regarding my HR and racing or even working out sometimes. I feel like my HR goes up very fast and stays there for quite some time when I do hard efforts like races that require you mostly to almost go all out if you want to stick to 1st group. Now what bothers me is that my FTP (223W @68kg = cca. 3.2W/kg) puts me in the top of C category but I still get beaten easily by riders who output about the same W/kg or even around 3.0W/kg. I also use ZwiftPower so after race I can see the results and other riders have much lower average HR than I do. I know that with higher age your HR tends to be lower but even though I am “only” 22 I feel like my HR is still waaaaay to high for the effort I do.

To give you an example I will give you data from today’s race:

My data:
Age: 22
weight: 68kg
FTP: 3.2W/kg
Average HR: 180bpm
Max HR: 192bpm
Time spent in HR Z4: 10:09 min
Time spent in HR Z5: 51:22 min

Winner of the race:
Age: Master (30-40)
weight: 92kg
FTP: Zwiftpower says 320w so that would be 3.47W/kg but he averaged 3.2W/kg for this race
Average HR: 169bpm
Max HR: 196bpm

Race data:
4x Park Perimeter Loop (NY) = cca. 39km
Total ascent: 504m

So I got dropped on the last lap on the “longer climb” (for those of you who know this track). I couldn’t hold even the guys in front of me since I hit the “wall”. Now is this due to me being out of shape in a way because it seems unhealthy to me that I would spend 51:22min in HR Z5 despite having the same W/kg. Is there really such a difference on flatter courses that my weight gives me almost no advantage even on shorter climbs? Is it normal to spend that much time with HR this high for my age? Is it normal to be at the max. W/kg you can have for C category and still not be able to end with the top guys?

I hope someone can answer to my questions, if you need more data please tell me what else to provide. Thank you in advance :slight_smile:

I’ve done plenty races on zwift and IRL where I’ve averaged up to 96% of my max HR for the entire race, sometimes over an hour spent at 190+bpm with my max being exactly 200. Some people can only hold 85% or even less, it’s largely genetic and not really an indicator of fitness or strength in and of itself. If you want to learn more about it then the athletic term is “Lactate Threshold Heart Rate” or LTHR. In short, the only useful heart rate data is your own.

How did you find your max HR? It might be inaccurate and low

Your max in general, not for that race. Your zones might be skewed

Yeah the zones and time spent in zone are from LTHR calculation from Garmin. I did LTHR test a few months ago and my LTHR is around 179bpm. So for Garmin watch settings I always use LTHR zones and not the regular ones or % of max HR.

This was max HR for that race. So far I’ve been able to reach 197bpm max which I think isn’t my max but it isn’t far away from it either.