heart rate confusion

[cinza]

I have a question about resting heart rate.

i read:

that a the fittest athletes could have a resting heartrate as low as 40...
I also read:
Old folk have a similiarly low heartrate.

i am 50.
my resting heartrate is about 52. (i think the expected heartrate for my age is 60)

so does this 52 heartrate mean i am getting really old or getting really fit?!!
or both? :rolleyes:

i am in excellent "athletic" condition... but i am 50....so i cant quite tell what my lower than normal resting heartrate telling me.

Second question.
Is there a definitive place to get info on heartrate and fat burning that also takes your fitness level into consideration?

Is it really better to stay around 70% when its still easy to be doing cardio at 85%?

sometimes i read that 70% + - is a rate that will help people maintain longer ... but working more intensily is good if you can.
But-
sometimes i read that 70% + - is really the rate that fat will burn at and its not beneficial to push it.

thank ya all...