I used the calculator, here:

www.sparkpeople.c
om/resource/calculator_tar
get.asp

Resting Heart Rate: 75
Age: 49

Target Heart Rate Results:
My heart rate ranges (in beats per minute)
55%: 128 bpm
60%: 133 bpm
65%:137 bpm
70%: 142 bpm
75%: 147 bpm
80%:152 bpm
85%: 157 bpm

I want to aim for 60-80% so 147 to152 bpm!
(very fit ppl can aim for 85%, or 157 bpm for me)