We all know a cardio workout is good for us. But how often do we need to do it to reap the rewards of miles logged on the treadmill or an hour of high intensity interval training (HIIT) in a group fitness class? And why? What is cardio? And what is the difference between cardio and high intensity interval training? And why is there a place for both?

Read on to understand and then how to add it in to your weekly routine.


What is cardio?


Cardio refers to any exercise that raises your heart rate. Your heart is a muscle, and just like all the other muscles in your body every time you use it gets stronger. In short, the stronger your heart the more fresh oxygen it sends to the cells in your muscles.


High-intensity interval training on the other hand is short spurts of…well…high intensity work where you push your body to at least 90 per cent of its ability. Unlike sustained cardio where you find a pace you can go at for a continuous period, HIIT is short bursts all out followed by active or non-active recovery.


Our partners at Les Mills say, “High-intensity interval training (HIIT) has made its name as a fitness game-changer, and there are plenty of studies highlighting its remarkably transformative effects. The results come from going as hard as you can for a short period of time, resting, and then repeating. It’s a formula that allows you to keep reaching your maximum training zone again and again, shocking your body each and every workout.”


There are a ton of benefits to high intensity interval training, or HIIT as it is commonly referred to. If you haven’t already, definitely check out our article here on some of them.


But they warn you can have too much of a good thing. New research has shown that adding volume to your HIIT workouts doesn’t necessarily translate to better results. For the most part, they report the stress HIIT puts your body under is beneficial – as it’s this stress that drives change. But your body is only able to handle a certain amount of stress at once.


In a high intensity interval workout, your body release stress hormones like cortisol. Cortisol can enhance strength, improve immunity and reduce inflammation. With that said, too much has a negative effect on your body, and therefore, too much HIIT can also have negative effects.


Don’t be scared, when done correctly HIIT can be extremely beneficial for the body. The key is recovery. When you adequately recover from pushing until you can’t push anymore, your body can absorb all the wonderful benefits of this type of exercise without the negative.


So how often should you do HIIT?


There is a lot of research into this type of exercise and its effects on the body. Our partners at Les Mills and the research they’ve commissioned suggest 30-40 minutes a week with your heart rate above 90 per cent. That translates on average to two 30 to 45-minute HIIT workouts a week. If you’re properly conducting a HIIT workout, a 30-minute workout would include 15 minutes of HIIT and 15 minutes of recovery. So, two a week would be just fine.


How to add it to your routine?


Since HIIT is by definition high intensity, it’s important to ease into it. Start first with a mix of cardio and weight training 4-5 times per week. Once your body is conditioned and your physical fitness is strong, begin by adding one HIIT workout to your routine a week in place of your usual cardio workout. When your body starts to get used to it, add an additional HIIT workout to your routine to complete two 30-minute HIIT workouts in one week.


Need a HIIT workout to start?


Try one of our awesome virtual workouts from the comfort of your own home. Choose from BODYCOMBAT, Conditioning, or one of Coach Andy’s Cardio Blasts.