HIIT vs LISS Cardio
Which Is Better & When
By Ash May
What Is HIIT Cardio?
HIIT is an abbreviation used for High Intensity Interval Training.
This is a method of cardio where short bouts of very intense exercise are broken up by much less intense active recovery periods.
For example, a 10-minute HIIT workout could look like this:
40 seconds – walking
20 seconds – sprint
Repeat x 10
This works best for cardio options where it is easy to quickly change the pace/intensity and is therefore popular with outdoor running, rowing, battle ropes, and body weight exercises.
What Is LISS Cardio?
LISS is an abbreviation used for Low Intensity Steady State cardio.
This is a method of cardio where the training period uses a consistent low level of intensity which is maintained for the entire duration.
For example, walking on a treadmill at a pace of 5km/hour for 40 minutes.
This works best for cardio options which can be completed ‘mindlessly’ rather than having to focus on what you’re doing so is often used with walking, cycling, stair climbing, and cross training.
Benefits of HIIT Cardio
High intensity interval training has several true benefits which make it superior to LISS training in some ways.
However, don’t believe everything you read about it as many of the claims made are marketing gimmicks – simply not true.
Here are the benefits that are true.
HIIT cardio will burn a high number of calories in a short amount of time.
This is due to the constant activity and bursts of intensity which can be sustained for a longer overall period thanks to the rest in-between.
Because of this, a 10-minute session of HIIT could burn upwards of 150-250 calories, whereas LISS would only burn around 75-100 in this same amount of time.
EPOC is an acronym for Excess Post-Exercise Oxygen Consumption – also known as the afterburn effect.
This is pretty much a fancy way of saying that HIIT cardio will increase your metabolic rate of several hours after performing the activity, meaning that you are burning more calories while doing normal activity, such as sitting at a desk.
Although this is a proven benefit of high intensity interval training, the significance of this is conflicted.
Some studies have shown that the daily increase of calories from EPOC is very minimal at around 10-20 (hardly worth writing home about) whereas other studies have shown much higher numbers up to 150-200 calories.
As performing HIIT cardio places the heart a constant state of increasing and decreasing, you are training your bodies cardiovascular ability in a much more demanding way than LISS cardio.
Because of this, it is likely that you will see better improvements in cardiovascular health, heart rate, and blood pressure (if yours is already high) in the long term from performing high intensity interval training.
Disadvantages of HIIT Cardio
Due to the intense nature of HIIT cardio, it places a much higher recovery demand on the body when used as a regular form of cardio.
This means that it needs to be used in moderation and carefully planned out, especially for individuals who also weight train alongside this.
The stress of weight training on the body is already high, so pairing this with intense cardio can easily lead to over training which will impair your weight loss rather than enable it.
As it is most common to use HIIT as a way of increasing calorie expenditure when trying to lose weight, we must consider the energy requirements – both physical and mental.
Although HIIT cardio is much faster to perform than LISS, it does take a huge amount of physical and mental energy within that time.
Due to being on reduced calories when trying to lose weight, it is likely that most of the time you won’t have enough energy to perform this.
That will lead to either reduced performance and therefore a less effective session, or will lead to you skipping the session and doing nothing instead.
Benefits of LISS Cardio
LISS cardio requires far less mental and physical energy/focus than HIIT cardio, meaning that you are much more likely to stick to a consistent cardio schedule, rather than skipping sessions.
This means it will be more effective for the goal you’re trying to achieve, even if it doesn’t seem to be more effective than HIIT looking from the outside in.
The low intensity nature of LISS can make it quite a relaxing experience which helps to destress, rather than being a stressful experience that HIIT can be.
Because of this, it often becomes routine easily and something that people look forward to doing each day.
Rather than having a detrimental effect on recovery like you will find with HIIT cardio, LISS will often help speed up and improve recovery from weight training.
This is due to the increased blood flow sustained for a period of time, but without a lot of stress being placed on the body.
This is known as active-recovery and is often used by athletes, but normal gym-goers can massive benefit from it also.
Disadvantages of LISS Cardio
By far the largest drawback of low intensity steady state cardio is the time commitment required.
What is achieved in a 10-minute HIIT session could take up to 3 times as long to replicate in a LISS cardio session.
This is a massive disadvantage for those who are time restricted, and already struggle to fit exercise into their busy schedule.
One of the most common complaints surrounding low intensity steady state cardio is that it is boring.
Obviously, this is individual, as some will find they really enjoy LISS cardio – it provides a good opportunity, to listen to music, podcasts, or even Netflix and YouTube.
However, due to the consistent low level of exercise you need to sustain for a long period of time in order to get the benefits of performing cardio, it is something which can become boring.
This can often lead to people being less consistent with completing it, as it feels like a large time commitment for something which is boring, and in this case, HIIT would be better for that individual.
With LISS cardio, you will be burning less calories per minute than you would be with HIIT cardio, which many people will see as a disadvantage.
The reasoning for why the per-minute calorie burn is lower is obvious, but depending on how cardio is used for you, this may not necessarily be a negative.
Which Is Best?
When compared in the short term, the benefits/disadvantages of LISS and HIIT cardio are almost completely opposite to each other.
They are drastically different, but there isn’t one which is a clear winner as it will come down to your individual situation.
A body builder who is 2 weeks out from a show won’t be seen doing HIIT sessions purely due to the energy requirement and recovery effects.
However, this may be the best option for a busy office worker who doesn’t get much opportunity for exercise during the day, and doesn’t necessarily eat perfectly.
So, as you can see, it really does come down to individual preference and needs. You need to assess the benefits and disadvantages discussed above, and see which is best for your lifestyle.
The long-term effects of both methods are actually very similar, as they will both improve your cardiovascular health, blood pressure, and more.
This is why it doesn’t really matter which you do, as long as you enjoy it, and stick to it!