I attribute this to the cycling. It's funny. I came home on leave, and went with my Dad to work. He did biomedical repair at a hospital. I was around 28-30. He had repaired a piece of equipment and wanted to test it. He hooked it up to me. My pulse was in the mid 40's. He thought his device was still broke because of my pulse. He could not believe it was that low. I cycled back then too.Wow Mark, your numbers are great. 30 years ago my resting pulse rate used to be ~45, now it's ~70.