Hi everyone.

Current Routine
I do 3 days of HIIT per week (my non-lifting days), 6 sprints per session, with 3 minutes in between each sprint. I discovered a great place for sprinting near me, around a long pond, and being around ducks, geese, flowers, trees, and other runners makes this so much better.

Side Tangent
The other 4 days are my lifting days. My gym is closed on the weekends, so those end up being my HIIT days. On lifting days, it generally takes me about 40 - 45 minutes to complete 15 sets (3 lift types, 5 sets each,) for that day's muscle group. There are 2 minutes in between sets, and some time is wasted waiting for a bench or machine to become available. If it’d be better to do 20 sets, or add some drop sets for the last sets of each exercise, then I can do that. I don’t go to failure on each set, I’m usually a few reps short of that.

Summary of HIIT Protocol
The protocol calls for 2 - 3 days of HIIT per week, 6 to 8 sprints with “a few minutes” in between the sprints. So at the maximum, in each week we’ll have 3 HIIT sessions of 8 sprints, with 2 minutes of rest in between sprints. I’m not quite there yet but at least I have the 3 days part down.

Possible Expansion? What is the most I can do, to get the best results?
In a few months I expect to have more flexibility and time as my business keeps ramping up and the money keeps flowing.

I could do HIIT in the mornings 6 days per week, and lift in the evenings 6 days per week. My philosophy with fitness and training is that you get out what you put in, and I feel that if you eat and sleep enough, overtraining is not really an issue. I would still get 5 days of rest for each muscle group (instead of my current 7 days,) so that I wouldn’t be overworking any one group. Would this be overdoing it, even though 6 days per week is recommended by many mainstream bodybuilders? I don’t feel weak post-workout.

Or is the recommended HIIT protocol the maximum that we can do before it becomes counterproductive? I feel like the answer to that is no, nobody has tested the absolute maximum but generally the more you put in, the more you get out. If you did 30 sprints and spent 4 hours in the gym every day, I’m sure that would be too much, I know there’s an upper limit but I feel like I’m nowhere close to it.

Basically, I’m willing to go above what the protocol calls for if it’ll help me get better faster. I feel like I’m not doing enough on the workout front. Thanks for any feedback / comments / suggestions.