[bitexploder]

As an ultra runner I can tell you 130-150 is "vigorous" in medical literature. Actually for anyone over 30, maintaining 150+ is probably threshold and providing you different kinds of adaptation. Ideally you spend 80% of your training time in Z3. You use Z4 to train VO2 max and Lactate Threshold. VO2 max is not very trainable. Lactate Threshold is. Z5, once you are "trained" and can run in Z3 for extended periods of time (30+ minutes) is almost purely for speed work and learning to run faster. It helps develop coordination and push through barriers. It is mostly anaerobic, so some amount of intervals in Z5 is good. Z4 is longer tempo work and fast/hard intervals.

Marathons are meant to be run at the edge of Z3 so you avoid hitting your lactate threshold. Think of your ability to run in each zone as separate gas tanks. Your Z5 gas tank is very small. Your Z4 gas tank can be trained, but is still relatively small. Your Z3 gas tank is basically unlimited (ultra marathon pace, 50+ non stop miles possible for almost any healthy human). Cardio is not about suffering.

Most people should be fast walking to maintain Z3 rather than suffer it out in Z4 and Z5 when they are getting started.

[taeric]

Is it the same for biking as running? My hunch is I was silly and looking at distance when I thought I could get more out of cycling. That is, I know I can bike 30+ miles with fairly little effort. Running 2 miles near kills me. (Granted, some of that is hernia related. Fixing that, but not expecting it to be easy any time soon.)

Checking my last long bike ride, I see I maintained 120 heart rate for majority of it. Which means I spent most of the time in zone 2, and makes sense that would be easy to maintain. (Contrasted with my last commute, where I cover 270 ft of elevation in about 7 minutes, mostly at about 160 heart rate...)

[photojosh]

A few years back when I was looking at Tour de France stats, IIRC a lot (most?) of those guys spend all day around 120 bpm too. The difference is that they are putting out pretty much twice the power that I do for that same effort.

And probably you too, given I have a hill around the same size on my commute that takes me around 7 minutes too.

[taeric]

https://www.strava.com/segments/622627 is the hill I'm talking about. Agreed that they are likely putting in much more power than I can at that heart rate.

My naive understanding is that I can push more time in higher heart rates and slowly pull up what I can do in the lower ones. That said, I'm just aiming to be consistently in the 6 minute time frame for that hill by next year. As things are, I'm quite winded if I hit the low 7 minute time frame. So, trying to pay attention to any methods I could use to make that better.

[photojosh]

Yep, just a little steeper than mine: https://www.strava.com/segments/623328

AFAIK your 'naive' understanding is pretty right on. I subscribe to the philosophy of spending as much time as possible in the "sweet spot" (search on that term), which is toned down just a bit from the best effort you can do in an hour.

[bitexploder]

Yep. Cycling has some different terminology, but the basics of zone training are the same. How much time per zone, intervals, training cycles, it all works the same in terms of adaptation.