Most people either love cardio or hate it, and a lot of that comes down to only ever having done one kind. There are two broad approaches, and they feel completely different: low-intensity steady state, or LISS, and high-intensity interval training, HIIT. Understanding HIIT vs LISS, what each does, how long each takes and which burns more, lets you pick the right tool for your goal and your day. Here is the breakdown from the team at Hammer’s Gym in Nunawading, along with how to use both on our floor and in our classes.
What is LISS?
Low-intensity steady state cardio means holding the same moderate pace and intensity for an extended period, usually 30 to 60 minutes, at around 60 to 70 per cent of your maximum heart rate. You can hold a conversation. A long walk, an hour of easy cycling, 40 minutes of laps at the pool or a steady session on the treadmill, bike, elliptical, rower or stair climber all qualify. Many people do LISS without knowing it has a name.
On the gym floor, set a machine to a pace and incline you can sustain for the whole session and settle in. If the length feels boring, watch a show or listen to a podcast, or set yourself up near the ring and watch the fighters train while you work. LISS is easy to recover from, gentle on the joints and can be done almost daily.
What is HIIT?
High-intensity interval training alternates short, very hard efforts with brief periods of rest or easy movement. Sessions are short, anywhere from 5 to 20 minutes, occasionally up to 30, and they can use bodyweight, weights or cardio machines: sprints on the air bike, hill sprints, kettlebell circuits or a class. HIIT pushes you to real fatigue, so it is demanding, but it is perfect for anyone short on time.
At Hammer’s, our HF45 (Hammer-Fit 45) class is 45 minutes of coached high-intensity interval training, and BoxFit and spin classes run through the week for the same effect. See the timetable and our ready-made 30 minute hybrid workout.
The three main differences
Intensity and fuel
LISS keeps your heart rate at a sustainable level where your body draws heavily on fat for fuel. HIIT pushes you to your limit and relies mostly on stored carbohydrate (glycogen). This does not mean LISS burns more body fat overall; total energy expenditure decides that, but it does explain why the two feel so different.
Duration
LISS needs 30 minutes or more to be worthwhile. HIIT can deliver a complete workout in 15 to 20.
Calories and the afterburn
Minute for minute, HIIT burns more, and the difference grows after you stop. Compare an hour’s walk with a 20-minute hill-sprint session: the walk might burn around 400 calories and the burn ends when you stop. The sprints might burn 250 during the session, but your body then works for hours to restore oxygen levels, replenish energy stores and repair muscle, so the total over the day can rival or exceed the walk. That afterburn effect, EPOC, is HIIT’s big advantage. Read how the afterburn works.
Which is right for you?
- Short on time: HIIT, two or three times a week.
- New to exercise or returning from injury: LISS first, adding one interval session once it feels comfortable.
- Fat loss: both, alongside strength training. One or two HIIT sessions plus daily walking (LISS in disguise) is a very effective combination.
- Training hard in other sessions: LISS, because it aids recovery rather than adding stress.
- Hate cardio: HIIT in a class, where the time flies and the coach does the thinking.
For the full range of options, see our comparison of the types of cardio.
Use both
Both approaches deliver results, and the best programs blend them: hard intervals when you want efficiency and intensity, steady sessions when you want volume, recovery or simply an hour to think. Your preference, goals and lifestyle decide the mix. If you have questions, chat to any of the team or a personal trainer and we will point you in the right direction. New to Hammer’s? Claim a free one-day trial in Nunawading, minutes from Mitcham, Blackburn, Box Hill and Doncaster.