HIIT Training: Don’t Make These Mistakes!

Fitness and Workouts

HIIT training. Quite arguably the best thing to happen to fitness since running shoes. A HIIT workout promises all the benefits of steady state cardio, but in half the time (or less!)

We live fast-paced lives and a workout that claims to cut down on the time we need to spend in the gym will get people interested. Unlike many fitness fads, HIIT has continued to be a go-to training method for many of us. And for a good reason. HIIT actually has some decent science to back it up.

What exactly is HIIT Training?

HIIT training (high intensity interval training) is a style of exercise in which you complete short bursts of vigorous exercise, followed by a recovery period. The goal is to increase your heart rate for a short period of time (a work period), followed by a decrease in heart rate (recovery period). For example you might do sprint intervals on a track or treadmill.

HIIT workouts that include both strength-based exercises and cardio exercises together have also become popular. Many bootcamp-style gyms have designed their entire program around HIIT training.

The Benefits of HIIT Training

Researchers have been studying the benefits of HIIT training for decades, and a HIIT workout has shown to be superior when compared to the same amount of steady-state cardio. When it comes to:

  • improving cardiovascular fitness
  • reduced resting heart rate
  • reducing blood sugar levels
  • improving cholesterol levels
  • increasing lean muscle mass
  • improving body composition
  • increasing oxygen consumption

Many studies show that HIIT training has steady-state cardio beat.

This is fairly logical considering the harder you work, the more demands you put on your body’s systems. This leads to adaptations to meet those demands. ie you become more fit.

It is also reasonable that in some studies, HIIT led to more fat loss vs steady state cardio. This is perhaps due to increased energy demands during and after the workout. Called the Afterburn, or EPOC (exercise post-oxygen consumption). You can read more about that here). For runners, HIIT workouts are a fantastic method for improving speed when training for a race.

How to do HIIT the right way

So, we know HIIT training is good. We also know it can be a great way to get a high quality workout done in a short period of time. But, it is also easy to do interval training incorrectly. There are endless variations in the way a person can do an interval training workout (for example with sprints, on a bike or rowing machine, or with strength-based exercises), but the key feature is that during the workout you’re alternating between work and rest periods; getting your heart rate up then recovering. Seems simple, right? But how long are the intervals? How high does your heart rate need to go? How long should the rest breaks be?

Today I’m sharing with you the biggest mistakes I see people making with their interval training, and sharing how you can fit HIIT into your training schedule the right way to get the most benefit!

Mistake #1: Your rest breaks are too short

Many runners think that during a HIIT workout you need to go as hard, and as fast as you can for as much of the workout as possible. In reality though, those recovery breaks are important, and should be given their due!

The recovery period is key for getting your muscles and brain ready to go again on the next interval. If you do an all-out sprint, take ten seconds to catch your breath, then try to do another sprint at the same speed, its likely that you’re just going to fizzle out. The next spring just won’t be as fast or as long as the previous one. Your overall workout quality will suffer.

Each recovery period should be at least as long as the work period, but often times it should be even longer if your work intervals are all-out effort. It should take a little time for your heart rate to come down after pushing that hard. If your heart rate has completely recovered very shortly after completing the interval, you may not be getting your heart rate as high as you really can during the work. Try pushing a little harder on the next one, knowing you can take all the recovery time you need!

Tip: Let your heart rate guide you! Invest in a heart rate monitor, or use the Borg scale (called rate of percieved exertion, or RPE scale). Research shows that people are surprisingly good at estimating how hard they’re working using this scale during exercise.

Mistake #2: Your intervals are too long

Now, there are styles of ‘interval training’ for runners that include intervals which are 3-5 minutes long. These workouts definitely serve a purpose during various training phases but wouldn’t really fall into the classic definition of HIIT. They’re missing the high-intensity part!

What happens is that because we’re striving to maintain this faster pace for a longer period of time, we just can’t reach the same level of intensity, and we’re stuck at a lower heart rate to make it work.

For most people who are short on time and want the best bang for their buck at the gym, a shorter, and more intense interval is the way to go. As I discussed above, these short but intense work periods are also shown to improve our health and fitness in a number of useful ways.

You should be getting your heart rate up to about 80% of your maximum heart rate (or up to a level where you find yourself unable to speak) Let’s call this a 17 on the Borg scale. Since this level of intensity is far too high for us to maintain for any length of time, a shorter work period (like 2 minutes at the absolute max) is the best use of your time.

If you are new to exercising, 80% of your max heart rate can feel very uncomfortable. It is important to start slow and listen to your body. Always check with your doctor before starting an exercise program if you are not currently active.

Mistake #3: You’re doing HIIT training too often

This is a biggie. So many runners get into the all or nothing mindset. Where, if interval training is good for us then it must be the only workout we need. But, intense exercise like this is a stress on the body. More stressful than lower intensity, gentler exercise.

While some HIIT training is great and beneficial, more doesn’t equate to better results. Excessive high-intensity exercise without adequate rest and recovery increases the release of our stress hormones (cortisol), which can further detract from our results. We can have appetite and sleep alterations, lose muscle mass, and gain body fat. We also increase our risk of injuries when we’re trying go too hard all the time.

Just like any other intense workout styles we need to alternate with easier ones for the best results. That means doing a HIIT workout once or twice per week, but the rest of the time doing strength focused workouts, mixed in with the bulk of our easy training miles. It often surprises people to find out that doing HIIT and only HIIT can actually slow down your progress! You might lose muscle mass, feel fatigued all the time, and even increase your risk of injuries. Leave a few days between HIIT sessions to ensure a proper recovery.

Proper nutrition is also key for supporting any amount of high-intensity training. Read more about the dangers of under-fueling here!

How to incorporate HIIT into your training program

For runners, include one or two HIIT days in your weekly training program. Because these workouts typically take less time, they’re a great addition to a day when you’re also doing some strength exercises. You can do sprint intervals before or after an upper body or core workout, or incorporate the strength and cardio into a single workout!

For example:

  • Complete a 10-15 minute warm up
  • Alternate between 1 minute of high-intensity exercises and one minute of lower-intensity exercise.
  • Use simple body weight exercises like jumping jacks, burpees, or mountain climbers to get your heart rate up.
  • Alternate these with strength training exercises such as a dumbbell fly, lateral raise, or bent over rows. Allow your heart rate to recover during these periods.
  • Finish with a 10-minute cool-down.

Tip: Use a timer to track your intervals. Many fitness watches have interval timers built in that are perfect for these types of workouts!

And, be sure to always avoid HIIT training when you’re recovering from an injury.

So, at the end of the day, HIIT is a great method for improving your fitness, shaving time off your race PR’s and can be done in less time than a 5-mile run. But, too much of a good thing can be, well, too much, especially if you’re new to exercising and don’t have the same work capacity of someone more advanced. Remember, we always want to train SMARTER, not just harder!

Some HIIT training advice for beginners

If you’re a beginner and want to try some interval training, that’s great! These types of workouts can be modified for all fitness levels. You might find that you are unable to get your heart rate up very high before it feels uncomfortable. If that’s the case, use the talk test to gauge how hard you are working.

During your rest periods you should be able to have a conversation. During your work periods you should be breathing hard enough that talking is more difficult. Work just slightly above your comfort zone. Your rest periods should be at least as long as your work periods, but take all the time you need in between intervals to feel recovered.

As you get more fit you’ll be more comfortable working harder. In total, the workout should take you 20-30 minutes.

Remember, always work out at the fitness level you’re at, not the level you WANT to be at!

What about a more experienced exerciser?

If you’re a more experienced exerciser, keep your work intervals under 2 minutes and focus on increasing the intensity of your intervals within that time frame. Your rest breaks should also be at least the same length as your work periods. T

he more intense the interval, the longer recovery period you’ll need. Each interval should feel as good and strong as the one before it. If you’re losing steam and can’t keep the same pace, increase the recovery period for the next interval.

It’s about having good quality intervals, not a bunch of half-assed ones. In total, the workout should still take you 20-30 minutes.

The bottom line

HIIT training has significant benefits for runners of all levels. It can improve cardiovascular fitness, reduce body fat, increase muscle mass, and improve other health markers. What’s really special about HIIT is that it can do all of that in less time than some of your training runs! But, more isn’t always better. Incorporating HIIT workouts just a few times per week into your training plan will help you avoid overtraining and get the most bang for your fitness buck!

If you are not currently exercising, or have health concerns always check with your doctor before starting any fitness program.

About the Author: Hi! I’m Stephanie Hnatiuk, a Registered Dietitian and Personal Trainer based in Winnipeg, Manitoba who specializes in helping athletes reach their peak potential with nutrition! Whether you’re getting ready for your first 10k or are a lifelong athlete, I would love to help YOU perform your best with a personalized nutrition strategy.