The HIIT Workout: Benefits & Risks

What Are the Risks and Benefits of High-Intensity Interval Training (HIIT)?

 High-intensity interval training, or HIIT, is a popular trend that touts fast fat-burning results with minimal (or no) gym equipment. It’s seen as the perfect solution for getting that much-needed calorie burn in a short period while many of us are stuck at home during lockdown. While HIIT certainly does have its benefits, it’s not a perfect solution for everyone, and there is a risk that it can do more harm to your body than good.

We’ve already talked about how HIIT may not be the best form of exercise for your body. In this article, we’re taking a look at both the risks and benefits of HIIT exercises, as well as the misperceptions about how our bodies react to high-intensity workouts.

Your Body’s Limitations

Research about HIIT typically looks at very short high-intensity sessions involving low-skill exercise (usually cycling or sprinting). When studying the benefits of HIIT, researchers typically look at very short intervals (around four minutes of total work completed). At-home HIIT videos or gym circuits are much longer than that. High intensity, dictates a very short duration and would suggest that longer HIIT sessions aren’t as intense as you might think. After 20 seconds, your body’s performance has dropped because you’re simply too tired to maintain that level of intensity and what continues to keep your heart rate high is the volume of reps/work you are doing.

There are only so many calories you can burn in a single workout, so even though your watch reading displays an increased heart rate, you likely aren’t burning the number of calories it says you are. With that said, your 15-minute HIIT workout is probably more of a weight-training circuit. It’s also important to remember that the gadgets we use to measure our performance aren’t sophisticated enough to give us accurate readings.

What Are the Benefits of Doing HIIT?

 HIIT is not without its merits, otherwise, it wouldn’t be as popular as it is today. Let’s take a closer look at its benefits:

 Increased Insulin Sensitivity and Improved Glucose Metabolism

In a Finnish study involving participants with type 2 diabetes and prediabetes, HIIT (as well as moderate-intensity continuous training) was shown to improve glucose metabolism and insulin sensitivity, which is beneficial to those with insulin resistance.

What’s the benefit of insulin sensitivity? Your body requires less insulin to decrease your blood sugar after eating, which reduces food cravings, improves brain function, slows development of neurodegenerative diseases linked to insulin resistance, such as Alzheimer’s, and makes it easier to burn fat.

While people with type 2 diabetes can benefit from HIIT, they should consult with their doctor before undergoing such intense physical exercise.

Mitochondrial Density

Your mitochondria are tiny organelles located in your cells that, to put it simply, convert food into energy. Studies have shown that high-intensity workouts can increase mitochondrial density, which better supports the breakdown of fat and carbohydrates.

Improved Resting Glucose Levels

 Research studying patients with type 2 diabetes found that resting glucose levels dropped after two weeks of HIIT. If you are prediabetic or have type 2 diabetes, performing high-intensity interval exercises can reduce your blood sugar levels and make your diabetes more manageable.

Let’s take a look at the risks involved with performing HIIT exercises:

What Are the Risks of Doing HIIT?

HIIT exercises are widely popular, particularly for people at home who don’t have access to heavy-duty gym equipment. But if you’re working out at home, keep in mind that HIIT comes with health and safety risks that shouldn’t be ignored.

 Greater Potential for Injury

Many people use HIIT to push themselves to the limit and this is where they can run into trouble. If you’re new to exercise, the risk of injury is even greater. HIIT-related injuries can come from a combination of factors, such as:

• Lack of adequate warm up or inadequate fitness level: due to the intense nature of HIIT, these exercises should only be incorporated into your workout only after you’ve acclimated to strength and cardio exercises. Knee and ankle injuries are some of the most common types of HIIT-related injuries, so strength and flexibility training are recommended before you try a more intense form of exercise.
• Poor planning: Whether you’re following a program or designing your own HIIT routine, there’s a chance you’re not balancing out your exercises or not giving enough focus on resting intervals.
• Bad form: HIIT is fast and intense and if you haven’t established the correct form, you’re much more likely (almost certain) to injure yourself. Even if you have the proper form, fatigue can set in before your workout is finished, which can then make it more difficult to maintain the correct posture.
• Ignoring the recovery period: True high-intensity training cannot be done frequently as the body cannot recover easily from it. There’s no real benefit in performing HIIT exercises more than two or three times a week, and yet, all-too often people are compelled to push themselves more frequently.

Improper Diet Can Slow Down Results

 High-intensity interval training certainly has its place, but if you’re only relying on HIIT to burn calories, you might be disappointed by the results. That’s because fat loss is largely due to diet, about 80%, in fact. Focussing on managing calorie intake by eating a balance of nutrient-dense foods contributes more to fat loss than high-intensity interval training.

It’s important to note as well, that if you’re on a low-carb diet, your body simply doesn’t have the glucose it needs to perform these high-intensity workouts correctly. Attempting HIIT when your body is low on glucose can lead to reduced muscle mass, poor workout performance, injury, and exhaustion.

Central Nervous System Fatigue

HIIT is extremely demanding on your central nervous system. If you try to squeeze in a HIIT workout more than three or four times a week, you could negatively impact your overall health as well as your workout performance. Even when you work on another major muscle group to give your worked-out area a break, you’ll struggle to reach the performance level you’re expecting because your central nervous system is simply too overtaxed. In other words, overtraining syndrome could be a real risk.

In summary, HIIT can help improve your body’s ability to regulate its blood sugar and boost its ability to burn fat when performed doing low skill exercise for very short bouts. On the other hand, it can also lead to long-term injuries and health problems when not performed properly or doing body weight forms of HIIT. There are many ways to achieve your fitness goals, and if you have pre-existing injuries or you’re new to working out, there are more suitable forms of exercise.

If you are interested in reading more about HIIT check out https://hiitscience.com/. The authors go through the best research into HIIT and its applications. It’s worth noting that there is not one piece of research in the book about body weight HIIT because that’s not how high intensity is achieved. 

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