My replies are below in BOLD
When going uphill, this generally means that you are resorting to walking, as running uphill very quickly elevates the HR to somewhere north of the “right” level. Those with a high aerobic capacity can in fact run up hill below their Aerobic Threshold. The fact that your HR shoots up indicates that you do not yet have sufficient aerobic capacity to manage that feat.
Now – I can walk uphill. I know I can do that. I’ve been doing that for years, and there is a speed that walking can get me to – but no faster. In order to be faster uphill, I would imagine that I need to learn to run uphill better… and the best way to do that is, indeed, to run uphill.
You can already run uphill. You ‘know’ how to do this. You don’t need to ‘learn’ this skill. What you need to do is to be able to metabolically support this up hill running effort with a higher percentage of fat vs carbs.
The problem, of course is this – in order to train “aerobically” I need to keep the HR down, but in order to practice actually running up hills I need to elevate the HR somewhat.
I guess the answer would be “find a hill that you can run up at your MAF level, then, when you can do that, find a steeper one, and so forth….” would that be about right? That is exactly correct. Find a lower angle hill that will allow you to run.
However, is there a point when the hill gets very steep, is it basically impossible to retain Aerobic levels of HR, and anaerobic levels simply have to overtake? Yes, but this will vary massively between individuals. One big problem with running steep hills is that running is not very economical on steep terrain so energy costs go up very rapidly. We all will be forced to switch to walk at some point for this reason.
Am I massively overthinking this? Not at all. Its great that you are thinking deeply about this and trying to figure it out.