My question is if I am spending too much time at too low of a heart rate.
Unlikely. Low intensity is never a bad idea, but it also depends on the session duration, weekly volume, and what has preceded it.
Don’t think I have ADS. Been following structured training for the last 3 or 4 years.
Years of training isn’t a factor. It depends on what you’ve put into those years. We see plenty of people that have been active for years, going too hard, and have destroyed their aerobic systems.
I got tested to find my zones in early 2020 and my AeT was 150, when blood lactate was 2mMol/L. My fitness may have improved in the last 18 months since I got tested.
What was AnT? HR and lactate? And what is your AnT HR / AeT HR ratio?
A typical week for me right now is around 16 hours volume. This includes a few long runs in the foothills with at least 1k elevation gain, my HR generally gets up to 135-140 on the uphill on these runs, but usually 120 or so downhill. Typically 128-130 average overall.
If AeT is 150, then this is perfect for high-volume.
One Muscular Endurance session – weighted hill carries, again usually in 135-140 on the uphill part, but then it plummets to below 100 often walking back down.
You can’t measure ME by HR because HR will underestimate the intensity. The real load is Z3 in the legs, but the central load (on your heart and lungs) will be lower. Count it as Z3 work.
And one long day in the mountains. This is where I am really wondering if I need to maybe go shorter duration, but faster.
Why? If big peaks are your goal, then a moderate amount of Z3 (as you’ve been doing) is fine. If you want to do shorter (~2h) events like a half marathon or skimo race, then yes, you’d need more speed work.
HR average was 120 on the way up. Then again it plummets on the downhill.
Sounds like a perfect volume pace to me, and HR will always drop on the downhill. To keep the same HR intensity would kill your legs from the impact.
My body sometimes feels at its limits, and don’t know if I could go faster to get HR up further, with this amount of volume.
Exactly, I think you’re training correctly. It’s normal that as fitness increases, the easy training becomes slower. One of my previous clients is a world-class runner, and we almost never trained at the top of Z2. It was too fast and too stressful.