Ah yes but a bit of regular cycling will get your pulse down to 45-50 bpm. Compared to the 60-70 it would be otherwise, even taking into account the 180 for four hours a week, I reckon that would be a net reduction:
((180-50) * 4) + (50 * 24 * 7) = 8,920 beats per week
(65 * 24 * 7) = 10,920 bpw
See, you'll live longer
