HIIT stands for high-intensity interval training: repeated short bursts of near-maximal effort separated by planned recovery periods. Both halves of the name carry weight — the intensity has to be genuinely high, and the intervals (the rest) have to be deliberate. Strip out either one and you have a different workout, often a perfectly good one, but not HIIT.
The structure exists for one reason: rest lets you visit an intensity you couldn't hold continuously, then visit it again. Those repeated visits to your top end are the training stimulus — the thing steady cardio, however sweaty, doesn't provide.
The anatomy of an interval
Every HIIT protocol is built from the same two blocks: a work bout and a recovery bout, repeated for rounds. The work-to-rest ratio is the main dial, and there's no single magic setting — the right one depends on your goal and current fitness.
- Short intervals: roughly 15–40 seconds of very hard work with equal or longer recovery — good for power and for learning what top-end effort feels like.
- Long intervals: one to four minutes at a hard-but-repeatable effort with recovery close to the same length — the workhorse for raising your aerobic ceiling.
- Rounds: enough repeats to accumulate meaningful hard minutes, stopping while the quality is still there.
What makes the intensity 'high'
'High' means an effort you could only sustain for a minute or two before slowing — breathing hard enough that speaking in full sentences is off the table. A useful self-test: if you could keep the pace going continuously for twenty minutes, it isn't a high-intensity interval; it's steady cardio at a firm pace. That's why real HIIT needs rest periods at all — the effort is unsustainable by design.
Heart rate is the most objective way to check yourself here, which is why interval training pairs so naturally with live effort displays like heart-rate training.
What gets mislabeled as HIIT
Plenty of workouts wear the label without the physiology. Forty-five minutes of continuous 'all-out' stations can't actually be all-out — the body settles into a moderate, sustainable output, which makes it a conditioning circuit rather than interval training. That's not a criticism; circuit training is excellent. It's simply a different tool, and knowing which one you're using helps you dose your week sensibly.
The tell is simple: true high-intensity work forces recovery breaks. If a class never needs them, the intensity was moderate.
Where intervals fit in a coached week
Because intensity carries a recovery cost, most people slot one to three interval sessions into a week alongside strength work and easier movement — the dosing question has its own answer at how many times a week to do HIIT. If you'd rather have the structure handled for you, Coresa's HIIT classes in North Vancouver run the format as coached, stations-based sessions.
Common questions
Is Tabata the same as HIIT?
Tabata is one specific protocol inside the HIIT family: eight rounds of twenty seconds extremely hard, ten seconds off, four minutes total. The original research version demands an intensity far beyond what most gym versions use, so treat commercial 'Tabata' as a format name, not a promise.
Do I need equipment for HIIT?
No. Hill sprints, stairs, and simple bodyweight efforts all work. Equipment like bikes and treadmills mainly makes intensity easier to reach, repeat, and measure — useful, not mandatory.
Is sprint interval training (SIT) different?
SIT is the harshest corner of the interval world: short, truly all-out sprints with long recoveries. It's effective but demanding, and most people are better served starting with hard-but-repeatable intervals.
Is HIIT cardio or strength training?
Cardio, primarily — it trains your engine. Sessions can borrow strength movements for the work bouts, and blended formats do both, but hard intervals won't replace dedicated resistance training.
