There are numerous benefits of both steady state cardio and HIIT – depending on what your main goal is, one may be more beneficial for you than the other.
I personally like to think of cardio not as a way to burn calories, but to promote a more positive hormonal profile.
Getting your body moving will release mood boosting hormones, as well as result in a higher cortisol output, which is why I always recommend cardio to be done in the morning/mid-day.
Cortisol should be naturally high in the morning and go down throughout the day and I find that starting my day with movement promotes a more restful sleep at night.
Sometimes I just go on a light walk because I personally find it a relaxing way to start my morning.
Other mornings, I will do HIIT. I prefer to do it in the morning, to reap the full benefit of EPOC, meaning that your body’s ability to process calories is heightened for the whole day.
I think the most common mistake people make when implementing cardio is doing TOO MUCH.
The body adapts quickly to repetitive aerobic exercise and it can also down regulate your thyroid function – both making you less efficient at burning calories and a less ideal environment for fat loss.
Chronic cardio or extended periods of cardio will result in excessive cortisol release (which is not something we want to).
Some of the best advice I can give you is to stop stressing about “burning calories” and focus on creating a more positive hormonal profile overall.