Don't fall into the trap that higher cadence is always better, it's just different. You will not really increase your speed with higher cadence, but you will both reduce the strain on your knees and increase your cardio workout.

If you have cardio issue, i.e. beta blockers, you may have to limit your cadence in order to get speed. I think best is to be able to run from 70 to 110 rpm for a steady five minutes of riding. Then you can naturally adjust your cadence as you feel on each day. It will take time and effort to get higher cadence, but it's sure nice to have it as an option. It's kind of like having another gearing option.