I’m transitioning back to mountain running (which I was good at 20 yrs ago!) after lots of time spent since indoor rowing and cycling. Having bought and thoroughly read “Training for the uphill athlete”, and previous return to running attempts thwarted by Achilles tendonitis, I can see that I’ve let my good level of fitness see me try and run too much too soon and too hard.

So I’m going very slowly and focusing on just building that aerobic base. I’m 48 yrs old. I’m not in a rush, I’ve made that mistake before!!

As I first started short mountain running/hiking sessions – I was hovering around 130-135 BPM, initially calculated using a combination of the MAF formula and the “can I breathe through my nose” methods. After 2 weeks this felt very slow and hardly out of breath (yes I know it can feel like that and I need to get used to slowing down). However when doing the same route session again, once I did it through just breathing through my nose, and found 140 BPM was the level I could comfortably maintain.

So eventually to my question – how often should I re-test what my AeT HR is (i.e. the max HR of zone 2)?

I’m not wanting to push too hard – I just want to focus upon building that aerobic base, whilst also very slowly building the running time (not bothered about mileage) and ensuring I don’t train and aggravate that Achilles tendonitis.