I am doing a simple strength training routine once every four days (Sxxx). I need to introduce a very low impact cardio day in this routine (e.g. SxCx). I would like to use the stationary bike (not the treadmill or elliptical machine) and I would like to keep it very simple, avoiding such things as intervals or HIIT. Just "classic" steady cardio on the bike.
It does not need to be the most efficient program. I just want to be sure I don't do anything unhealthy out of ignorance.
The bike has a built-in hear rate instant meter. How should I approach training my heart under that circumstances? Is the following naive program unhealthy or ineffective? 30 minutes at 60% of my max HR. The next session (four days later) I aim for 61% and so and so until reaching 30 min at 80% of my max heart rate (or until the month of June arrives and I switch to swimming).
For those who are about to answer "it depends on your goals": well, my average resting heart rate just before quitting running was 53 bmp, and now it is 66 bpm. I just want to lower it down again. The strength training alone is definitely not training my heart.