For those of you who are into a balance of strength building and cardio increase building exercises, I found a simple chart to "check" one's BPMs range when cardio building. Good tool when using a TreadMill (with BPM monitor handles) or Statonary peddle bike (with mini-BPM monitor on the arm).
When cardio build exercising, remember to check BPMs - to ensure the body isn't being under worked or being over worked. For me, I keep the body within 160-170 BPMs (which is good 80%-90% range for my older age body).
Hope this helps others...