[Spexxvet]

I schedule 3x per week, but too often something more urgent interferes.

I learned a long time ago that once a week puts more stress on your heart, because every time you do it, it's like starting over. Twice a week keeps you where you currently are. 3-4 times improves you. 5 -7 increases the likelihood of injury beyond the benefit.

YMMV, and this information could be outdated.