Really enjoying the Training for the Uphill Athlete book and have learnt so much from it already. My problem is trying to accurately assess where I am without using my heart rate as a guide because I cant rely on it.

I have Lone Atrial Fibrillation (it doesn’t come and go its permanent, always there). Iv had it at least 20 years probably longer, been under cardiologists etc and don’t need any treatment for it, they are happy with the way it behaves and so am I, it causes me no issues other than I naturally have a higher resting heartbeat than most. I have always previously run 10k’s & half marathon trail races (all with medical approval to do so) but approx 4 years ago I lost interest and stopped running. Now enjoying running again and want to take a more holistic approach and try MAF Method base training instead of how I trained previously. The problem is, as always, I can’t get a steady heartbeat due the how AF works, it can fluctuate from 90 – 150BPM in less than a minute due to the way the faulty electrical signals operate with this condition and AF sufferers naturally have a faster heartbeat anyway.

Any ideas on how I could incorporate the principles of the MAF Method and staying in HR Zones 1 & 2 when running without the need to follow my heart beat as its not possible for me and i’m struggling to know how to accurately measure whether I am in an aerobic state or i’m moving out of this state in to more anaerobic zone 3 training etc. Also LT testing isnt possible because i dont have the data to calculate my progerssion. Up to now I have been basically running very slowly (just a fraction faster than walking pace) and breathing through my nose only, three second inbreath and 5-6 second outbreath. I can do this quite easily with very little effort over 7 miles plus but its still not an accurate measurement it’s more a guess as to what is actually happening internally and whether I am operating within my personal aerobic zones only.

Iv just ordered an optical arm strap to see if that might work as a chest strap just picks all the chaotic elecrtical signals my heart produces so the data is of no use.

If there any any other good approaches i would love to hear.