HIIT Cardio is NOT Good for the Morbidly Obese

HIIT Cardio is NOT Good for the Morbidly Obese

I am an expert in this - I was a morbidly obese woman who happened to try doing HIIT and almost died... Well, not really, but there were a lot of issues that were brought up when I did attempt HIIT.

Just a bit of background. When I say I was “morbidly" obese, I mean that I was 300 pounds, not like I just had 20 pounds to lose. No offense to others that have 20 pounds to lose, but having a whole person to lose can be a little daunting.

HIIT training is high-intensity interval training, which I feel a fat person has no business doing. I am sure I will get crucified for this statement, but I do have reasons behind it that I will go into.

Being a former fatty, I hurt everywhere. If I walked my knees and hips hurt. When I did down dog, my top half was so heavy I could only hold it for five seconds. I couldn’t breathe if I laid on my back.

My heart rate would shoot up to the 200s if I did 5 air squats. FIVE.

I know what you are thinking. “They did it on the biggest loser and they lost weight!” What they didn’t show you were the contestants that fainted, had to be sent to the hospital or hurt their knees/hips. They lost weight, but at what cost.

However, let's throw some science at my skewed perspective, shall we?

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In the International Journal of Biosciences (yes, there is such a thing), they did a study with 208 obese, healthy males between the ages of 30-45. The study tried to determine if a low-calorie diet with high-intensity training was better than a low-calorie diet with endurance training, or if just a low-calorie diet was better.

In this study, they also calculated the CRP, which is an inflammatory biomarker that is increased in fat people, but right now, we don’t care about that.

Sorry fat people, you are inflamed.

Their HIIT for the subjects were running with high intensity at 85-95% VO2 peak with one minute of recovery (ie to get down to a VO2 peak of 55%) and did 4-6 sets during 12 weeks and increasing the VO2 peak and sets to 10 by the time they were done.

Lordy, that is a lot of jargon. But basically, they wanted them to have their heart beating out of their chest for 4-6 sets running their face off, then give them a 1-minute break so their V02 came down, then do it all again.

Surprise, surprise. Everyone lost weight in every category. OK, not really a surprise, I suppose, but.

They surmised in this study that post-exercise oxygen consumption was higher in the HIIT subjects. However, there were no significant changes in data for the ones that were doing endurance training or diet alone.

Oh, wait, I have another study. This one is done on 33 obese individuals and shows that continuous aerobic training actually improves fat distribution independent of weight loss, but the HIIT group didn’t improve fat distribution.

Don’t get your panties in a wad, people.

I totally believe in HIIT. The metabolic effects and the improvements made the to the cardiovascular system are absolutely amazing.

Your capacity to improve your VO2 max is totally there with HIIT, and can provide cardio protection for someone with heart disease. Also, it reduces

systolic and diastolic blood pressure. Oh, and it improves insulin sensitivity, let's not forget that.


Let's not forget about the pounding of joints, the grinding of bones and the pain that gobs of fat have jiggling off your body. I know that sounds crude, but remember, I was that fat person that trainers wanted to do HIIT with.

As a fat person, I can speak to this well. Its total crap when someone says, “No pain no gain.” I say this because every time I did HIIT I not only hurt, but I usually injured something because of the impact.

And people wonder why I hated the gym...

So, what can a fat person do to get the benefit of the above without all the pain?

4 Cardio Tips for the Morbidly Obese

1. A modified HIIT will do

It’s not a “true” high-intensity interval training, but it can be close.

I know that as a fat person, I would do anything for two minutes (um, yeah, just walking) my heart rate would shoot up to about 200. So, when I started to do HIIT training to help myself get better at just walking, I did intervals of marching for one minute, then resting for two minutes. Gosh, maybe even three minutes.

This is what I did for about 20 minutes. 1-2 times a week just to get me geared up to walk for up to six miles with my walking group.

2. Monitor your heart rate

For God's sake, monitor your heart rate. If you feel like your heart is going to explode out of your chest, knock it off.

I mean it.

I have come close to fainting many times trying to do what my trainers wanted me to do. Barfing, fainting and then pooping your pants really didn’t feel like that was the best choice for me in front of a whole gym full of people.

So tone it down. Get your heart rate up to a fat burning zone, not an “Oh my gawd I am going to die” zone.

3. Do endurance training

If you are obese, you probably have very little endurance.

Obviously, that is a generalization and there are always exceptions to the rule. However, most morbidly obese peeps are out of breath in like five minutes walking at an incline of 15 and three miles an hour.

I am speaking from experience, here, but getting one's endurance up can also enhance your “cardio protection” by lowering your blood pressure and making you more insulin sensitive - maybe to a lesser degree, but still will do the trick.

4. Obviously, eat right

I don’t know why I threw that in there, but I know some people who think they should work their face off at the gym but think they are totally immune to food and can eat whatever they want.

No. That's just not how this thing works if you want to lose fat.

In Conclusion

Stop the insanity. HIIT is a great tool that has great effects on work capacity, insulin sensitivity, and cardiovascular protection but does very little for fat distribution.

It is difficult for a morbidly obese person to perform, and can actually be detrimental to their health. It is funny, but all the fitness magazines basically say, “Fat person, suck it up,” (in so many words) and really had very little empathy for joint pain or even accounting for any type of injury this subset of people may have occurred during a HIIT session.

One popular online fitness magazine even inferred that at an obese client unwilling to do HIIT can be a sign that they are lazy and don’t want to do the work it takes to get their weight off.

That's ridiculous and ignorant in my opinion. Anyone would be unwilling to subject themselves to risk of injury and pain.

However, as a morbidly obese person loses weight, HIIT would be a great addition to their workout regime, as would lifting weights.

1) International Network for Natural Sciences- Research JournalInternational Network for Natural Sciences – Research Journal, www.innspub.net/wp-content/uploads/2014/05/IJB-V4No9-p190-196.pdf.
2) "Metabolic Effects of HIIT." New Mexico's Flagship University | The University of New Mexico, www.unm.edu/~lkravitz/Article%20folder/metabolicEffectsHIIT.html.
3) "Continuous Exercise but Not High Intensity Interval Training Improves Fat Distribution in Overweight Adults." Hindawi, 16 Jan. 2014, www.hindawi.com/journals/jobe/2014/834865/.
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Damon - October 28, 2019

HIIT workouts are completely subjective to the individual and is just as effective for overweight individuals. If you’re 300 lbs then walking would be considered a high intensity workout because you’re 300 lbs. If I’m 150 lbs and walk while holding 150 lbs (300 lbs total) that would turn my low intensity walk into a high intensity activity. There isn’t one HIIT workout that will work for everybody, it doesn’t matter whether you are obese or not. If I try to swim at the same intensity as Michael Phelps for as long as he can, I will die regardless of my weight.

Kim - August 7, 2019

thank you, thank you, thank you for being brave enough to write this! This is exactly what I already New, and I’ve been searching for something that feels better and something g I can be excited to incorporate!

Jingles - September 18, 2018

Clearly you were not doing HIIT correctly. In fact it’s scary to see your experiences here.

HIIT is about reaching a certain percentage of your max heart rate (I aim for 90%), then popping down (I go to 75%) and then back up again. NOTHING in HIIT says to go over that. If slow walking brings you to 90%… well then you slow walk. And nothing says it has to be joint-bearing exercise, either. I started at my highest weight doing HIIT in the pool. One lap at 90%, one lap much slower, one lap at 90%, etc. There are plenty of options that don’t stress the joints and yet allow you to do HIIT safely and with amazing results.

Chris Moody - April 12, 2018

I have been having a problem similar to this. I have been in and out of the gym, and when I first get in I am fired up, I try to hit everything that I can and kill myself doing cardio/training that people half my size have trouble doing…Then, at some point, my back or knees will get so bad that I will take time off, I will get discouraged, and then my gym visits become less and less frequent. Reading this has really helped to remind me that I don’t have to show up ready to work myself to death, just to work the longer, harder path to successful and sustainable fat loss while protecting my joints so that I can continue to lose weight as efficiently as possible.

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