When Using HIIT Workouts ISN’T The Answer

hiit cardio
Endless HIIT got you going in circles? Might be time to change things up…

Chances are if you’ve been a reader of this blog, or any fitness blog for that matter, you’ve at least heard of HIIT (high-intensity interval training).  It’s a form of cardio that involves short bursts of all out intensity, mixed with longer, slower periods of a more relaxed pace.  It’s touted as a great means to slash calories, churn through body fat, and get you into the best shape of your life.  That’s all well and good, but does that mean HIIT is right for everyone, with every goal, 100% of the time?  Ehhhh….I’m not so sure.  I’m going against the grain today, and throwing myself to the mercy of the masses.  I’ve actually been doing this quite a bit lately – has anyone seen my article on why the Paleo Diet is based on a bunch of no-science nonsense?  So at risk of taking another e-beat down from hordes of fanatics, I’m going to explain to you why HIIT workouts may NOT be the best thing for you, and in fact, why they may be the one thing preventing you from reaching your goals.

Is HIIT Right for YOU?

First things first, what are your goals?  This is something you must absolutely be asking yourself when you’re designing your own exercise program.  Are you trying to add muscle to a scrawny frame?  Lower your body fat percentage by a few digits?  Drop 80+ pounds?  Your goals matter.  They are going to dictate exactly what, and how much, you should be doing.

Second – what is your diet like?  Are you on a low-carb diet?  Are you cutting calories to drop weight?  Are you going super heavy on the protein in an effort to add muscle mass?  These things are especially important to recognize when determining what type of cardio you should be doing, as well as the level of intensity to be working out at.

Thirdly, I want you to ask yourself what your current routine is like.  Do you tend to skew more towards heavy weight training sessions, perhaps some metabolic conditioning, circuit training, etc?  Or are you more of a cardio hound, always hitting the treadmill, stationary bike, or row machine.  The components of the rest of your workout are going to dictate what type of cardio you should be doing.

All of these factors are going to go into determining the best type of cardio for YOU.  Remember, no matter how matter of fact some of these fitness experts speak – exercise is NOT an exact science.  What works for you, may not work for someone else, and vice versa.  There are thousands of biological and chemical factors inside your body that differentiate the way you’re going to respond to a specific type of training.  To make it simple, figure out your goals, your diet, and analyze your current fitness program.  Once you’ve done that, and made it through this article, it should become perfectly clear whether HIIT is right for you or not.

When HIIT Workouts Aren’t The Answer

Are Your Goals Pretty Standard?

So as I mentioned above, lets start by looking at your goals.  If you’re like most people, you tend to be pretty average – you’re not significantly overweight, but you do have a few pounds you’d like to shed.  You probably also wouldn’t mind getting a little more muscle tone and definition.  Am I right?  If your goal is to simply tone up, build a little muscle, and improve the appearance of your physique but NOT serious fat loss (i.e. 30+ pounds) HIIT may not be the answer for you.

You see, HIIT workouts are a serious workout.  Their intense nature often has you working near your maximum heart rate value, which results in tons of calorie burn.  But wait, isn’t tons of calorie burn always a good thing?  Again, if you don’t have a ton of weight to lose, the answer is a resounding NO.  Burning tons of calories is great when you have tons of calories to burn, but if you’re simply trying to drop a few pounds of fat while simultaneously improving your physique by the accumulation of lean muscle mass, performing tons of HIIT cardio is going to stop that accumulation of lean muscle mass dead in its tracks.

I don’t care how hard you’re killing it on your weight training days, if you’re using HIIT training to frequently, it’s going to chew up any gains you’ve made and spit them right back out onto the gym floor.  Burning fat and building muscle at the same time is a very delicate process.  It’s a very fine line to walk (some would argue it’s impossible), and by working out like a crazy person on your cardio days, you’re going to completely destroy that fine line. Keep things balanced to allow yourself to grow muscle and slowly but surely trim away that excess fat.

How’s that Diet?

Going hand in hand with the above point, is your diet.  Your goals and diet are the perfect partners – they’re going to set the tone for everything you do in the gym.  Have you been on a low-carb diet in an attempt to drop body fat.  Maybe a low-calorie diet instead?  If you’re like most people who are actively trying to drop body fat, you’re under eating.  When your body is deficient in carbohydrates, or calories in general, performing a crazy intense workout like HIIT sprints is going to have an adverse effect on your body.  And here’s why…

Glucose is the main energy source of our body – it’s what our cells prefer.  When you perform loads of intense cardio (or even weight training for that matter) your body is going to zap those glucose stores to allow you to continue working at a high-level.  Makes sense right?  Hard work is going to burn up more glucose.  Now, when you are deficient in carbohydrates because you’ve restricted your carb intake AND you’re working out very intensely, your body is going to turn to other sources to produce glucose.  What are these other sources you may be wondering?  Well, the body is quite efficient at turning amino acids (aka muscle tissue) into glucose to be used for energy.  What this means for you is, if you’re not getting enough carbs, but still working out like a madman/woman, your body is going to burn away your muscle tissue to allow you to continue working out at that intensity.

So when you’re out there killing it on the treadmill, thinking you’re just crushing through fat, it’s entirely possible, you’re primarily crushing through muscle.  This is basically the last thing in the world you want if you’re trying to improve your physique.  I’ve mentioned before how static-state cardio can turn your body into soft, flabby, mush….well that doesn’t mean HIIT cardio CAN’T.  If you’re not on a diet that supports HIIT cardio, the effects it takes can be disastrous to your overall goals.

Are Your Weight Training Workouts Suffering?

Have you ever tried doing a heavy weight workout a day after a very intense cardio session, or heavy lower body day?  Often times, you’ll find yourself unable to lift with the same maximum intensity and force, despite the fact the muscles you’re targeting are completely rested and generally feeling great.  The reason for this is your CNS (central nervous system) is depressed due to the previous day’s workout.

The CNS is the source that drives the power your muscle deliver on the weights you’re trying to lift.  If you don’t have a great driver because it’s become overworked from a previous workout, you’re weight training sessions are going to suffer.  I’ve seen far too many people, in an effort to drop body fat, go so hard on their cardio days, and completely slouch on weight training days.  This feeds the situation mentioned above – too much cardio, not enough weights, and perhaps an inadequate diet, will only lead to a soft, flabby, and mushy body.

You need to be giving it 100% maximum effort during your weight training workouts if you want to make a lasting change to your body.  I cannot overstate the importance of an effective and well-balanced weight training program if you’re trying to tone your body and build muscle definition and an athletic physique.

The Big Takeaway

The main thing to take away from all of this is that HIIT cardio, despite all of the touted benefits and praise that gets heaped upon it, may not be the best thing for you.  Personally, I’ve been doing a bit of experimenting with myself and have replaced with 2-3x weekly HIIT cardio sessions with two static-state cardio sessions of 20 minutes each.  While this may not be enough cardio for some people, it’s more than enough for my body.

hiit cardio workout
Want a better body? Time to shift your focus from cardio to weights.

Unless you are primarily looking for an all out reduction in body weight I would shy away from using HIIT cardio more than once a week.  Even at once a week, keep sessions short and intense, i.e. no more than 25 minutes. Go for additional cardio sessions on the elliptical or stationary bike, maintaining a nice, steady pace for 20-30 minutes.  Even better though, shoot for uptempo weight training sessions, along the lines of metabolic conditioning routines to ensure you’re effectively working your cardiovascular system, as well as burning the appropriate amount of calories.

So who is HIIT right for?  HIIT is great for people looking to maximize their cardiovascular endurance, improve speed, agility, and aren’t primarily concerned with body aesthetics like the rest of us vain a-holes.  Don’t get me wrong, HIIT is effective in helping shed tons of calories and improve endurance, but if you’re teetering on the edge of average, and just want to add some muscle to a soft frame, it’s not the best choice for you.

To reiterate, this information is primarily geared towards the person without much excess body fat, who wants to build lean muscle, increase definition, and improve their physique.  It’s simply too difficult to build muscle in your legs, butt, biceps, etc when you’re performing super intense cardio, such as HIIT, multiple times a week…UNLESS you’re eating to sustain that level of intensity.  Since most of you guys aren’t packing away 3,000+ calories a day, it would be wise to cut back on the HIIT, amp up the fast-paced strength workouts, and place a greater focus on building lean muscle mass and eating healthy; two components which will absolutely help you reach your goals faster than anything else.



13 thoughts on “When Using HIIT Workouts ISN’T The Answer”

  1. Thank you for helping me understand all of this. There are so may differing reports which makes things confusing. I feel comfortable with your thoughts. Thanks for sifting through everything and being the voice of reason.

    1. I know it can be confusing/contradictory, I experience the same thing when I’m trying to learn something new for myself. If it helps put you any further at ease, I try to base my opinions and subsequent posts, on as much peer-reviewed scientific study data as possible. Of course, there is never one exact answer, but I think, as far as this post goes, you can feel pretty good taking this one to the bank. Thanks for your comment and hope to keep seeing you around here!


  2. So excited to come across this article! I’ve been considering adding a lot more HIIT to my workouts in order to shed extra pounds for an upcoming event. This helped me understand the dos and donts.

    1. Glad it could be of help to you Ashley! Please let me know if you need any other help/ or some more formal guidance. Our FitPlan exercise program has been delivering some pretty killer results for some of our readers..let me know if you want to get a little more info on it!


  3. Nice article. I just started using HITT with my workouts to help stir things up a bit you might say, thanks for the reassurance.

  4. Hi Matt, I’ve been doing the superset mini complex workout you have here for about a week now. I am also exactly what you described above. I want to shed about 5 pounds and increase muscle mass. I also take body attack about 3x a week. Is this too much like with he HIIT workouts.

    1. Hey Leisha –

      If you’re trying to increase muscle mass, the added cardio that comes with the HIIT plan MAY be too much. Remember, building muscle will help you burn more fat in the long run, so make this your primary goal since you don’t have much fat to lose (~5 lbs). Personally, I think you would be best suited going with a customized plan that will specifically attack the goals you have in mind. If you’re interested, let me know and I can put something together for you.


  5. Great article! I’m low carbing to lose those last five stubborn pounds. If glucose levels are low, then can u body use your fat stores as energy during hiit, or will it always break down muscle to convert protein to glucose? Thx Matt!

  6. Great post! I am a trainer and use HIIT often, but I agree it is not always the best workout. In fact, I was just talking to a client the other day who is experiencing heart issues from over training with HIIT while following a low-carb diet. Unfortunately, people think low-carb + HIIT is a perfect match, but it is definitely not.

  7. great article!! This is exactly like speaking to me. I am trying to lose few pounds, looks more tone and was going on a low carb diet, i did HIIT 3 times per weeks, steady cardio 3 times per weeks and weight lighting 2-3 times per weeks as well. Guess what, i didn’t lose much weight and my period stop coming.
    Should i change my diet or it is okay to stay with the low carb diet, but remove the HIIT? Just continue with the slow & steady cardio + weight lighting?

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