Do I need to be fit to start HIIT?

No — every move scales. Look for classes labelled Beginner or All Levels, tell the coach it's your first time, and take the easier option whenever you need it. You build the fitness by showing up, not by starting fit.

How often should I do HIIT?

Two to three times a week is plenty for most people, with rest days in between. It's intense by design, so recovery is part of the programme — not a sign you're slacking.

Will I be sore afterwards?

Likely for the first few sessions, especially in your legs and core. It eases as your body adapts. If something sharp hurts during a move (not just muscle burn), stop and ask the coach for a swap.

Getting started4 min read

A beginner's guide to HIIT

HIIT — high-intensity interval training — has a reputation for being brutal. It can be, but it doesn't have to be: "high intensity" just means high for you, and every move can be scaled. Done right it's one of the most time-efficient ways to build fitness. Here's how to start without overdoing it.

What HIIT actually is

HIIT alternates short bursts of hard effort with short recoveries — say 40 seconds of work, 20 seconds rest, repeated. The work can be bodyweight (squats, burpees, mountain climbers), a bike or rower, kettlebells, or a mix. The point is the intervals, not any one exercise.

Because you're pushing hard then backing off, you get a big training effect in a short session — most classes run 30 to 45 minutes. Your heart rate climbs in the work phases and settles in the rests, which is what builds cardio fitness over time.

What your first class is like

A coach demos each move, then you cycle through stations or follow the clock as a group. Expect to sweat and to be breathing hard — that's the design. A good coach gives an easier and a harder version of every exercise, so you pick the level that lets you keep moving with decent form.

"High intensity" is relative. For your first few sessions aim for about a 7 out of 10 effort, not a 10. You should be working, but able to keep your technique together. Speed with sloppy form is where injuries come from.

What to wear and bring

Supportive trainers, breathable activewear, and a water bottle — you'll need it. A small towel helps. Studios provide the equipment (mats, weights, bikes); you just turn up.

Eat something light an hour or two before rather than training on a full stomach, and don't be shy about resting an extra few seconds when you need to. Finishing strong beats blowing up in the first round.

Is it right for you?

HIIT suits people who are time-poor and want cardio and strength in one hit, and it scales from complete beginner to very fit. If you're new to exercise or returning from injury, start with one or two sessions a week and tell the coach — they'll keep the impact low (swap jumps for steps, for instance).

Give your body a day between hard sessions to recover. More isn't better here; consistency two to three times a week beats hammering it daily and burning out.

Ready to try HIIT?

Browse HIIT studios across Ireland and book your first class on FitFinder.

Find HIIT near you All studios

Common questions

Do I need to be fit to start HIIT?: No — every move scales. Look for classes labelled Beginner or All Levels, tell the coach it's your first time, and take the easier option whenever you need it. You build the fitness by showing up, not by starting fit.
How often should I do HIIT?: Two to three times a week is plenty for most people, with rest days in between. It's intense by design, so recovery is part of the programme — not a sign you're slacking.
Will I be sore afterwards?: Likely for the first few sessions, especially in your legs and core. It eases as your body adapts. If something sharp hurts during a move (not just muscle burn), stop and ask the coach for a swap.