3 Pitfalls of High Intensity Training to Be Aware Of

Posted by Beni Cook
Is HIIT all it’s cracked up to be?

High Intensity Interval Training (HIIT) has gained in popularity over the last decade, and is still the talk of the town in many fitness circles. Touted as the best way to lose weight and improve fitness, there certainly are benefits to HIIT. But did you know that too much HIIT can be a bad thing?


What is HIIT?

HIIT is a form of training that focuses on short, high-intensity exercises to get your heart rate up quickly. Originally designed for athletes looking to improve their stamina and aerobic fitness, it’s come to be used as a quick-fix solution for everyday people who want to lose weight fast.

Research shows that HIIT sessions can be more effective at burning calories than activities like jogging, where your heart rate stays the same throughout the workout. However, a 2021 study shows that too much high-intensity training can actually reverse the positive impact the exercise has. Here’s some of the major ways HIIT can negatively impact your body.


1# Too much HIIT can unbalance the hormones in your body

While exercise is generally good for your health, it does cause the body stress, especially during taxing high-intensity workouts. One of the risks with HIIT is that this stress can put strain on your adrenal glands and spike your cortisol levels. Cortisol is the hormone that the body releases when it is stressed and is where our ‘flight or fight’ instinct comes from. While this is an important and natural occurrence, high cortisol levels can lead to digestive issues, anxiety, and weight gain.

One of the most common side-effects of high cortisol levels is hindering your sleep. There are many studies that show exercise has a positive effect on our sleep, but a high-intensity workout close to bed can make it difficult for you to doze off. HIIT workouts should definitely take place earlier in the day, but that’s not all you need to worry about. Chronically high stress hormones can negatively affect your sleep in the long-term – so if you find you’re unable to sleep at night, it might be time to cut back on the HIIT workouts.


2# High-intensity workouts put strain on the body

Any exercise has the risk of injury, especially with improper technique. With HIIT, the danger is in its name – anything ‘high-intensity’ is likely to cause strain on your body. Poor technique in HIIT workouts has been known to cause joint issues and injuries, particularly when high-impact movements such as box jumps and burpees are involved. If you have any existing injury, or are new to high-intensity workouts, you’re asking for trouble.

Joint issues become even more of a concern if you’re pushing yourself through your HIIT workouts. If you overdo your workouts, you’ll start dreading them, leading to unfocused and unmotivated workouts where slip ups are common. Not only can you injure yourself if you push yourself to do a HIIT session you’re not into, you’ll also become demotivated and burnt out.


3# Excessive HIIT could stop you burning fat

Another effect HIIT has on your body is depleting glycogen stores. As you exercise, your body uses the sugar in your blood as fuel before moving on to glycogen, which is a form of energy storage. This is essentially how you burn fat – sounds like a good thing, right? The problem with depleting your glycogen stores is that you still need glycogen to fuel your body between workouts. If your stores aren’t replenishing, you’ll end up fatigued, slowing you down during workouts, and inhibiting recovery after exercise.

As we mentioned above, studies also show that too much HIIT can stop your body burning fat – ironic, given that’s probably the reason you started HIIT workouts in the first place. In a recent 2021 study, researchers found that participants improved their health and fitness when they started HIIT workouts, but once workouts were increased to 5 times a week, the results began to reverse. Excessive HIIT training negatively affected their metabolism, causing disruptions in their blood sugar and insulin levels and hindering the body’s ability to burn fat.


So, how do you know if HIIT is right for you?

There are many factors to consider when it comes to HIIT and whether or not it’s the right training for you. If you do want to give it a go, or continue your training, it’s best to stick to one or two high-intensity sessions a week, broken up by low-intensity workouts. HIIT workouts should also last no more than 30 minutes at a time, including warm-up, rest, and cool-down.

If you feel like HIIT isn’t working for you, it’s ok to give it a miss completely. Low-intensity aerobic training will yield wonderful results. You can always start reintroducing some high-intensity training into your workout, even if it’s 5 minutes between lower-intensity activities.

If you’re unsure what training program is best for you, we’re here to help. Get in touch today to learn how our personal trainers can tailor a program to suit your needs and goals.

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Beni Cook
Beni Cook is the Head Personal Trainer and Founder of Beyond Best. Beni is a health and fitness expert who develops individualised exercise programs that will meet your own short and long-term objectives, while providing information, advice and encouragement that will enable you to lead your healthiest life, every day.

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