Workouts for Cardio

I want to try to use Karate more constructively to improve my Cardio-vascular health. The exercise is definitely good for me, but I want to see if there are specific things I can do to work out more effectively.  

I have been lucky enough to be able to join a Karate group on Facebook that offers a mentoring scheme, and within that I was lucky enough to find a mentor who is willing to work with me to help me develop specific exercise routines for use at home.  

After going over the basics, it seems that the best way to start is to do more of what I'm doing already, but more regularly.  Then we get to review things on a week by week basis to gradually build up the routine.

This is one 57 year old that doesn't intend to give up easily 😈😈😈