I love HiiT too, find it alot more rewarding than SSCV
Just my 2p though
Becuase HiiT is so intensive its best done after 2 meals or so in order to ensure glycogen stores are full, and help ensure your primed anabolic before doing a very catabolic training session.
I'm not quite sure how you managed 45 minutes of hit. For me ill do a 5 minute warm up, then will run with a 1:1 split. 30 seconds best effort, 30 seconds active recovery. Best effort will be something like 5% gradient sprints at 19km/hr. Then recovery will be walking at 6km/hr at a 5% gradient and so on.
If im using the rower then ill aim for 500m times of less the 1:50's.
You keeping a general training log anywhere?
T13