What actually makes it HIIT
High-intensity interval training alternates short bursts of near-maximal effort with brief recovery, relying on the anaerobic energy system almost maximally during the work interval, which is what separates it from steady cardio at a hard-but-sustainable pace. A full session typically runs under 30 minutes total, work included.
Real HIIT protocols use specific ratios, not vibes. A traditional format uses 20 seconds of work to no more than 10 seconds of rest. A more moderate version uses a 2:1 ratio, something like 30 to 40 seconds of hard effort followed by 15 to 20 seconds of easy movement. The Tabata protocol, one of the most studied formats, is 20 seconds of ultra-intense work followed by 10 seconds of rest, repeated continuously for four minutes.
The session
Five-minute warm-up (light jogging, dynamic stretches, a few practice reps of each move below at half effort), then four rounds of the Tabata-style block, 20 seconds of work at maximum effort, 10 seconds of rest, cycling through four exercises per round:
That's one round, roughly two minutes. Rest 60 seconds between rounds. Four rounds is a full 12 minutes of intervals, bookended by warm-up and a cooldown walk.
How to know you're actually at HIIT intensity
The 20-second work interval should feel close to maximal, hard enough that holding the same pace for a full minute wouldn't be possible. If you finish a 20-second interval feeling like you could easily do another 20 seconds at the same effort, the intensity is too low for it to function as HIIT rather than moderate cardio. This is the opposite failure mode from the beginner circuit: here, going too easy is the mistake, not going too hard.
Sources
- High-intensity interval training, Wikipedia