Good Morning.
I am seeking some guidance.
First off I am 65 years old and lift twice a week following 531 for Beginners. Most of my conditioning has come from walking.
I recently purchased an Airdyne with the intent of eventually using it for HIIT a couple days a week. Since I am just started using it I thought I would build up slowly with Zone 2 before transitioning into HIIT.
My question is after becoming adapted to 45 minutes of Zone 2 riding what would be a good beginners program to begin HIIt on and airbike.