alt Hacker NewsN=1, but I started rowing (indoor, on an erg) an hour a day -- not hard, generally 120-140 bpm -- every day starting February 28, after rowing inconsistently for a year or more before that. My resting (not sleep) pulse has dropped by 10% over the past ~7 weeks, from 60 to 54.
General advice: citing absolute HR numbers is pretty meaningless for a broad audience, because they are not intepretable. Express them as percentages of your current max HR to be meaningful to others.