Cardio is an important part of any fitness regime, whether you exercise for better heart health or to lose body fat. But knowing exactly what to do can be confusing. Some people swear by low intensity, steady state (LISS) cardio like cycling, swimming, or power walking. Others think high intensity interval training (HIIT) is the best way to burn calories and change your body shape in a short space of time.
Which is best for you? And do we have to do official cardio sessions at all, or is it enough just to raise everyday activity levels by walking and moving more?
Like many things in the health and fitness world, the real answer is “it depends”. Let’s examine both approaches side by side.
What is LISS?
LISS – “low intensity steady state” cardio – is any kind of cardio that feels low intensity and that you do at a steady pace. It usually hits around 50-60% of your max heart rate. You could still hold a conversation doing LISS (although you might sound out of breath!)
What is HIIT?
You won’t be able to talk during HIIT (“high-intensity interval training”)! It is short periods of very intense effort, followed by longer periods of lower intensity to let your heart rate recover so you can go again. You do this high/low combo several times to make a HIIT session.
How do HIIT and LISS work?
Both HIIT and LISS are cardio training, so their main objective is to raise your heart rate and burn calories (rather than build muscle). In terms of fuel source, LISS uses mostly fat, and HIIT uses more carbohydrate. But don’t think that means HIIT won’t help you burn body fat. It definitely does! LISS cardio burns a higher percentage of energy from fat, but actually burns fewer calories than HIIT.
Research suggests that HIIT is better than LISS at improving your cardiovascular fitness, heart health, and fat loss. And HIIT will help you hold on to more muscle mass, because it uses explosive efforts which act like resistance training. Good news if you care about the shape and look of your physique, not just losing weight.
One thing we love about HIIT is the EPOC (excess post-exercise oxygen consumption) effect. Because you work hard during HIIT, your body continues to burn calories after the session. LISS doesn’t do this.
LISS is less demanding than HIIT, and our bodies get used to it pretty quickly. This means your body will adapt to your LISS training over time, but it never gets the chance to do this with HIIT. It’s the difference between biking to work using a steady pace, or doing sprints on the bike. Once your body has adapted to LISS, the only option is doing a longer session. That’s not very appealing when you need to gt more from your session.
HIIT can be adapted through intensity, or by changing the type of exercises you do. The duration of the entire session doesn’t need to change. Good news if you need to get your cardio done quick!
Power walking outdoors
Uphill treadmill walking
Steady bike rice
Swimming at a steady pace
Which Cardio Is Right For You?
Any cardio is better than none at all. But you need to find the best form of training to fit with your lifestyle and routine.
Very few of us have time for longer and longer LISS sessions. So HIIT is a great tool for getting things done in just 20 minutes or so, a few times a week. It’s the kind of cardio workout where you can get in and get out quickly, knowing you’ve worked hard and made some real changes to your fitness.
If you’re worried that you won’t work up a sweat doing HIIT, think again! You’ll get a great endorphin rush and definitely feel like you’ve worked your body hard. And you don’t need to be super fit to do HIIT. Adapt the “intense intervals” to suit your own fitness levels at the time.
LISS is a good addition for days when you feel tired, or sore, or simply want to move your body without impacting your recovery. A long walk outside or a gentle bike ride has plenty of physical and mental benefits. It’s good “me time” to get outside and move your body at your own pace.
But for “calories per minute”, HIIT gets our vote every time. It’s the cardio to use for calorie burning, fat loss, and actually changing the shape of your body to a leaner, tighter physique. That’s good news if you are training for strength and fat loss.
We’re in Team HIIT!
The Bottom Line
Any kind of cardio movement burns extra calories in your day and keeps your FitBit happy! So move your body, get your steps in, and try not to be sedentary for too long at a stretch. Remember that fat loss comes down to a calorie deficit, whatever kind of cardio you use to help create it.
But the “best” cardio is the type you enjoy enough to keep doing it. And we reckon that HIIT will give you faster more visible results… which will keep you motivated.