What Hippo said.
It's crucial to measure your own figures correctly. Just using the numbers you've quoted above as an example - for me, 147 bpm is equivalent to 70% which I use as a ceiling for my effort levels on long runs. (My average HR tends to be around 142 - 143.) Now if I tried to maintain 159 bpm on, say, a 15 mile run I doubt I'd even want to finish it, and I'd definitely be overdoing things.
Work out your MHR and enjoy the training!