If you do want to incorporate HIIT into your overall diet and physical activity:
1. First talk to your doctor.
2. Choose one or more modes of cardio: walking, cycling, elliptical, rowing machine, running, etc.
3. Work intervals should be 45 sec or 1 min at the beginning.
4. Intensity should be at only a somewhat hard to hard effort. Challenging, but not overwhelming.
5. Work to Recovery Ratio should be 1:3 or 1:2. This gives enough time for your Aerobic Metabolism to refill your skeletal muscles with ATP, the energy needed for your next bout.
6. Do this twice a week only. The rest should be steady state cardio and resistance training.
7. Have fun! Don't break your ass doing these workouts!