If you’re at all interested in fitness, then chances are you’ve heard of high-intensity interval training, otherwise referred to as HIIT. Perhaps you’ve read about it online, seen it discussed in your favorite fitness magazine, or simply heard others talking about it at your local gym. Whatever the case may be, there’s a good chance what you heard sounded something like, “HIIT is the only way to burn fat” or “If you aren’t doing HIIT, you’re wasting your time in the gym.” Or maybe it said, “Steady-state cardio doesn’t burn fat — HIIT does, and there’s no other way to train.”

We are being bombarded with statements like these, and they’ve led everyone to jump on the HIIT bandwagon. If you’re going to the gym, you’re doing HIIT. It’s that simple. But, is HIIT right for you?

It’s important to question what you read and hear about HIIT, because most of these sources don’t have your best interests in mind. Is HIIT really worth the hype? Let’s look at a few factors that may make you think otherwise.

HIIT Is Extremely Intense

Let’s get one thing straight. HIIT is the most intense form of exercise you can do. This is what brings forth the benefits it has to offer. For some people, this is great. Intensity is the name of their game and they are fully prepared to go that extra mile and put in that level of work.

For others, it’s a recipe for disaster. Take your average gym-goer as an example. They’ve just started their workout routine. They likely went to the gym because they have 20 pounds to lose — or more — and are ready to finally do something about it. Prior to joining, their activity level consisted of little more than getting up to look for food in the fridge or going for a walk here and there, but only when they found a burst of motivation.

These are usually the type of people who love instant gratification. After all, instant gratification is what got them in this position in the first place. The cake was tastier than the apple, and therefore it’s what they ate. Now, they have this excess weight and are looking to get it off pronto. They aren’t looking to take the long journey to weight loss. So, when they hear that HIIT is the fastest way to burn fat, they jump onboard.

The issue with this is they aren’t actually ready to jump onboard. They’re out of shape and need a slow and steady approach, not one that calls for 110 percent of their effort at a near-maximal pace. Unaware of this fact, many attempt HIIT anyway — and then one of three things happens:

1. They become injured — HIIT will put you at a higher risk of injury if it’s not done properly.

2. They don’t perform it correctly, preventing them from reaching the intensity levels that characterize HIIT. Thus, it’s not HIIT.

3. Or, they try it, hit those intensity levels, and hate it so much they leave the gym forever.

For these reasons, a person who wishes to lose weight shouldn’t go down the HIIT route. Instead, they should get started on the exact type of exercise they’re apprehensive about: steady-state cardio training. This type of exercise will help them build up their fitness levels to the point that they feel comfortable moving on to HIIT sessions successfully.

HIIT Is Taxing On the Central Nervous System

Another often unaddressed issue with HIIT is that it’s very taxing on the central nervous system. Any form of high-intensity exercise, whether it’s HIIT cardio training or weight lifting activities, is going to wear you down.

The problem with this is HIIT is often emphasized as being the only way to burn fat, so people who are highly motivated attempt three to four sessions per week. Then, they pair that with three to four sessions of intense weightlifting per week. While they might sustain this regimen for a few weeks, their body will eventually grow tired. Some people will even see this fatigue as a sign they aren’t training hard enough and begin upping the intensity even more.

People who overdo their workouts may injure themselves. Photo courtesy of

This fatigue is often a sign that a person needs rest. Pushing forward too much can lead to full-blown overtraining, which often causes symptoms such as an altered resting heart rate, muscle soreness, sickness, loss of concentration, insatiable thirst, and even personality changes. It can also cause injuries bad enough that they’ll be sidelined, not doing much of anything.

HIIT can be good if you are at a fitness level where it’s possible, and even then, it should be performed in moderation. A balance between rest, recovery, and intense training will lead to optimal results, but many people aren’t able to do this successfully.

HIIT Requires the Presence of Glucose

Finally, you might want to forgo HIIT training if you’re on a low-carb diet. When it comes to weight loss, diet will always trump exercise in terms of the results that can be seen. It’s just far easier to cut calories than it is to burn them off in the gym.

Therefore, diet should be priority number one. But if you happen to be on a reduced-carb diet — one that’s been proven effective in burning fat — you might not have the necessary fuel to complete HIIT.

HIIT is an anaerobic form of exercise, meaning that the body needs fuel in the form of glucose to get through it. If you are taking in a limited amount of carbohydrates, there simply won’t be enough glucose to fuel your workout, especially if you’re doing strength training too.

This will cause your performance to falter and you won’t hit the intensity levels you’re aiming for, even if you have the best intentions. When this happens, you have two options: you can either add more carbs to your diet plan or replace HIIT with a lower intensity form of aerobic cardio that uses fat as a fuel source. For many people, the likelier option to choose is the second one. It’ll keep their low-carb diet intact and they’ll only have to adjust their exercise plan.

There’s no denying that HIIT can be highly beneficial when performed under the right circumstances. Unfortunately, it simply isn’t ideal for everyone. Don’t fall for the hype that HIIT is the only right way to train. That just isn’t the case.

Shannon Clark holds a degree in Exercise Science from the University of Alberta, where she specialized in sports performance and psychology. In addition to her degree, she is an AFLCA certified personal trainer, and has been working in the field for over 12 years now. You can learn more about her at www.ShannonClarkFitness.com