An 8 week block of Long Slow Distance training would probably lower your resting heart rate enough. Using MAF's formula subtract your age from 180. That number and that number -10 gives you a general 10 bpm range you want to walk, jog, bike, row, etc for 3 sessions of 45 minutes each per week.
For example, I'm 45, so 180-45=135bpm. My range is 135-125 bpm.
This is the range that fills your heart with blood completely, and with time will cause it to grow larger, and have a higher stroke volume. Like going from a V6 to a V8. More displacement. The sprints listed above will train your heart to contract harder, but won't increase it's size and give you a much lower resting heart rate. You need a heart rate monitor, or a piece of cardio equipment that monitors heart rate. Polar straps that pair with your phone are really good.
Just a thought.
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