Thanks @Silverdarling!
Interesting shift -- it seems he's going beyond the 3x per week with 3x20sec per HIIT workout that his original experiment suggested. One question I have as I start out with HIIT is how many days/week I should do it without worrying about overtraining and all that rot.
A suggested week-long plan for a beginner to HIT might include skipping for as fast as you can for 90 seconds before resting and repeating, sprinting for 20 second intervals on day two, sprinting on an exercise bike for eight seconds, then 12 seconds recovery and repeat over four minutes, running up stairs and walking back down over four minutes on day four and cycling in a fast burst of three minutes during an eight minute long cycle on day five.
Interesting shift -- it seems he's going beyond the 3x per week with 3x20sec per HIIT workout that his original experiment suggested. One question I have as I start out with HIIT is how many days/week I should do it without worrying about overtraining and all that rot.