At my Level 1/Maffetone heart rate, I can run on flat or gently undulating terrain for hours.
AT THE SAME HEART RATE when going up an incline above 15% the perceived effort is so high that I feel like I am only just hanging on and am glad when 20 minutes is over.
Question:
What do I need to do to be able to reduce that perceived effort and climb for hours at my Level 1/MAFF heart rate?


PS: I do do a LOT of hill reps.