One of the largest issues that I have with interval training, and more specifically the advice on how to do hiit cardio or interval training, is that very few people ever talk about the negatives to it. Now I'm not here to preach about all the bad things associated with interval training. I actually like it and it has obviously been proven by research that when you compare it to a steady state workout, you'll lose more fat doing intervals. All that has been established. I really have two issues with it.
The first being that almost no one monitors their fatigue levels when they do interval training or hiit cardio. It's just taken as something to do to burn more fat. 90% of the population in general will not monitor their progress or recovery at all. As a matter of fact, they'll just go to the gym Monday through Friday and not look back. That's a big issue. Hiit cardio is very central nervous system fatigue; more so then steady state work. So I do not really understand why someone would recommend against adding steady state work in, at least one time per week to both continue calorie burning and aid in recovery.
The second and largest issue that I have with typical hiit or interval cardio recommendations is that no one builds in a success plan. What I mean is that none one progresses themselves with their intervals. Look at it this way. Steady state work gets bashed on a lot since the only way that you can increase your results is to spend more time doing it. Sure, you can raise the intensity of hiit cardio by going faster or extending your intervals or by adding more but it's really the same. You will eventually run out of options, no?
So what are you to do then?
The answer is to never let it get to that point. Do not begin with the basic understanding of interval cardio, which is 30 seconds on and 30 seconds off. It works when you first start training but not after that. Now before you start screaming that I'm only speaking to well conditioned people, hold up. If you are new to this then you should not be doing intervals anyway. You can not just jump in the ring and box can you?
The answer is to clearly plan your hiit cardio breakout. Let's say that you are going to go with 30 minutes of hit, plan each 60 second frame as it's own workout. The limits are endless, make one block a 32 second sprint with a 28 second jog or walk. How about adding in a steady state aspect half way through? At the 15 minute mark, jog for 3 minutes. I mean you've already forced your body to use stored carbohydrates for energy? Why not take advantage of all the fat that is just floating around and burn it with a different mechanism? The options are endless.
Here's a quick video I made that gives you a interval training overview