I have opposite issue, high Z2 puts me to ~86% of LTHR. Same time, there is no aerobic decoupling for quite long durations (~6h). For day to day training, I do cap Z2 rides at 80% of LTHR. But is it something to worry about, though?
Don’t think I’ve seen the talk test mentioned in this thread.
The ability to have a conversation whilst riding Z2 is a good measure. You should know you’re working but be able to speak in complete sentences.
If riding solo then I do the alphabet test. Whilst sat down not doing anything recite the alphabet and remember what letter you reach before needing a breath. Then try and repeat that during your Z2 rides. If you can manage to within a couple of letters that’s good, but if you can only recite 4 less letters before needing a breath you are likely working too hard.
You can tune that into what heart rate / power that comes out to after a while. But the talk test holds regardless of your fitness.
What do you mean by high Z2? HR, power?
Power, 70-75% of FTP. To keep HR in check, I do Z2 rides at ~60-63% of FTP.
I have no idea what that is. Does LTHR work? I got this from sufferfest test at the start of the year.
CTHr means lactate threshold for cycling, the lactate threshold will be different depending on the sport and muscle groups that are involved.
High z2 70-75% puts me at 80-90% LTHR.
If I sit at 60% ftp my HR is closer to 75% LTHR. Oddly, for me it aligns with that 180-age lol
Meant that I ride in power Z2 but HR goes already to HR zone Z3.
I’m not an expert, the numbers I gave are just another generalization, but a better one than 180-age. As aerobic fitness increases, your Z2 power increases in proportion to FTP and FTP increases as a proportion of power at VO2max.
The only way to know your Z2 power for sure is to do test protocol that involves taking actual blood lactate tests.
Oh, sorry, misread OP indeed. Yeah, I am in same camp as he is 
- 5min 333W (from ramp test)
- FTP 269W (by AIFTP and can really hold it, ramp test puts me at 275W, which could hold ~35-40min)
not more recently but at the start of the year it was pVO2max (5min test of sufferfest) was 300 and ftp was 236, so about 80%.
Ramp test around the same time, i got up to 320w
I’d guess its probably similar now with a lower ftp and lower pvo2max but i’ve not tested.
I really appreciate the help figuring this out.
I tend to over think things in the attempt to get the optimal (not necessarily perfect) approact/plan and given endurance work is completely new to me, im wondering around in the trees, unable to see the woods.
So whta would you suggest for z2 work?
Thank you.
Yeah, I have thought same, that’s why stopped doing SS and switched to more traditional base
Well I for one dont think you are mad.
Given where i am aerobically at the moment would you say continuing to target zone 2 (lower z2 or upper z2) is the way to go.
Today i was planning another 90 min z ride but closer to 60% given i did 70-75% yesterday and i have squats/deadlifts tomorrow. (plus train now suggested a lower intensity z2 ride for the endurance option)
I’d rather go out in a Scottish (or Hertfordshire for that matter) winter wonderland where I know the roads will be treated right 
I also wonder if it’s a generational thing. As a kid I always cycled to school from about 7 years old up. Before that I walked with another family from down the street. Cycled in winter, and all weathers, and pedalling through the snow didn’t stop you getting to school. Lot of kids seem to get driven now, rather than on own two feet or by bike. A kid being driven to school was as rare as hens teeth when I was at school.