It is important to know what your target heart rate zone is when you are exercising so you don't overexert or injure yourself.
Each individual has their own target which is can be figured by a couple of methods.
The most accurate method to calculate this number is to use the Karvonen method.
You start by taking the number of heart beats for a full minute after you have been sleeping or sitting quietly for a few minutes. Most people fall between 60 - 90 bpm. We will use 60 as an example.
Next you need to figure your age-predicted maximum by subtracting your age from the number 220. We will use the age 40 for our example. 220 - 40 = 180. 180 is the age predicted maximum.
We then subtract the resting heart rate from the age predicted max. 180 - 60 = 120.
We take this number and multiply it by .60 and .90 (the recommended percentage of your maximum heart rate of 180 per the example). By doing this, we get 72 and 108.
We then add the resting heart rate back into each of these numbers and it will give us the estimated target zone:
72 + 60 = 132 the low end
108 + 60 = 168 the high end
Staying within the calculated 132 - 168 zone will yield the greatest fitness benefits without overexertion or injury.
I have just found online that there are fitness programs complete with music that are made for especially for all the different target zones.
MARINA's High-nrg Fitness Music & Workouts is one such site that offers these unique exercise routines.
I can see where these would be a great motivational tool that would actually work.
I know that I listen to my MP3's quite often while I am walking, and there are some songs that just fit perfectly with my stride and steps - I bet a whole CD of them would be perfect and it would keep me in the range I need to be in.
Definitely something to look into!