Your intervals should be attempted at MAX effort. Make sure you take the full recovery to let energy replenish before you go MAX again!
30-45mins very easy
Super LT session with one min hard efforts to build lactate tolerance and mental toughness.
This is a hard anaerobic session only to be completed by fit and trained athletes after a solid period of mixed intensity training. This will challenge and improve your aerobic fitness as well as develop anaerobic endurance. Ride the efforts at a high cadence and then recover.