They say I've got a big heart

I just woke up to a resting heart rate of 34 beats per minute. Thats 3 beats below my previously seen all time low. Is my heart supposed to slow down as I get older or train better! I'd better look this one up on the www next time I'm bored. I think I read that the heart gets bigger with more training and subsequently pumps more blood per stroke. Or maybe I'm just getting older.