Training for 70.3
If you're using a chest strap, make sure it's clean. I was registering a HR of 200+, which I knew was way out, until I put it in the washer and that corrected the issue.
I take it you're following an 80 / 20 plan and trying to stay in zone 2. I had the same problem, easy to keep to zone 2 on a trainer but almost impossible when running or riding on the road. I kept using a HRM, keeping records of its readings, but go by perceived exertion instead, the basis of zone 2 appears to be the age old advice that if you can comfortably talk to a companion you're at the right place.
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