I joined the Our Future Health programme (https://ourfuturehealth.org.uk/ - I recommend it if you're in the UK), and as part of that had to undergo various tests (blood test, cholesterol, blood pressure...).
The nurse had to do the blood pressure test three times to be sure the machine was working correctly, because apparently my heart rate is so low (49, while normal range for adults is 60-100).
In my case this is a good thing rather than a bad thing, because it's a result of all that running (if I didn't exercise a lot, it could be a bad thing).