My fellow coworker and our senior trainer here at Spectrum, Dave Knight, ATC, CSCS, CISSN, said something about steady-state cardio one day that has stuck with me since the day he said it.
“You can’t work less hard and expect to burn more calories and get better results” he said.
Short, sweet and to the point.
And it’s 100% true.
First, it’s important to define what high-intensity intervals and steady-state cardio actually are before diving into the differences between the two.
What is High-Intensity Interval Training?
High-Intensity Interval Training (also known as “HIIT”) involves alternating bouts of intense exertion just below or right at your maximum aerobic capacity (also referred to as VO2 max), followed by low-intensity “active recovery” periods. Simply put, these highly intense bursts of effort cannot be sustained for very long.
What is Steady/Slow-State Cardio?
Steady-state cardio is a low-moderate intensity form of aerobic exercise extended out for a longer period of time (often >20 minutes). Jogging, walking, long-distance swimming and cycling are examples of this form of exercise.
“So which one is more effective in burning fat? I’ve also heard of something called the “fat burn zone,” what’s up with that?”
Hold your horses, I’m getting there.
There’s one more crucial thing you need to know when talking about exercise and fat burn. That thing is called EPOC, also referred to as “the afterburn.”
EPOC is short for “Excess Post-Oxygen Consumption.” In plain English, you place your body in an oxygen debt when you go through any form of exercise, regardless of intensity. Much like a bank, you pay your oxygen debt back once you’re done exercising and returning to homeostasis (resting levels) by taking in more oxygen than you did prior to engaging in physical activity. It has some catching up to do!
THE FAT BURN ZONE.
Yes, it exists. But it has been misinterpreted, thanks in large part to gym equipment companies who place that stupid little fat burn zone chart on their treadmill, bike, stair stepper or elliptical in order to make themselves look good and try to sell more units. We’ve all seen them before and it’s no wonder why people get easily confused by them.
The fat-burning zone is a concept that the body burns a greater amount of calories from fat at lower-intensity aerobic exercise than it does at higher intensities.
This is true. Fat WILL be your primary fuel source while jogging your 5K, walking your dog, or swimming endless laps in a pool.
So congratulations! You are now in the illustrious and ever-so-coveted fat burn zone!
But here’s what most people miss or simply don’t understand, and it’s very important.
As it pertains to exercise, the most important component of fat burning is the intensity of the exercise, NOT the distance or duration.
So with that said, here’s the bad news.
Because the intensity level of steady-state cardio is too low, your afterburn will not last long after your workout is over to stay in this sought-after zone. As a result, you will not continue to burn calories at a high enough rate to make enough of a difference over the long-term.
Womp womp. Bummer.
So what makes high-intensity intervals so special you may be wondering?
Refer back to Dave’s quote to begin this post. When it comes to fat loss, there’s no other way around it. You need to place yourself in a total energy deficit in order to see the scale move backward and watch fat mass start to shrink. That means at the end of the day, you need to burn more calories than you consume or take in. And yes, I fully understand that’s much easier said than done.
Of course your diet and how you choose to consistently fuel yourself is what will have the biggest impact on improved body composition. But more on that in later posts and for the sake of staying on topic.
Bottomline: by accomplishing just as much work (if not more) in a shorter period of time with a higher intensity, you will place yourself in a greater oxygen debt and burn more calories both during and after exercise with the help of your afterburn than slow-state cardio.
And obviously, burning more calories will only help you on your quest to losing more body fat!
Still not convinced? Don’t take my word for it. This little research blurb is directly out of page 37 from the 3rd edition of the National Strength and Conditioning Association’s “Essentials of Strength Training and Conditioning” textbook:
Recently, a series of short-term (two-week) interval training studies used six sessions of four to seven 30-second maximum cycling efforts inter-spaced with 4 minutes of recovery (1:8 work-to-rest ratio). These studies demonstrated improvements in muscle oxidative potential, muscle buffering capacity, muscle glycogen content, and time-trial performance as well as doubled aerobic endurance capacity.
The benefits are explained further still from Muscle For Life, (https://www.muscleforlife.com/high-intensity-interval-training-and-weight-loss/):
Increased resting metabolic rate for upward of 24 hours after exercise.
Improved insulin sensitivity in the muscles.
Higher levels of fat oxidation in the muscles.
Significant spikes in growth hormone levels (which aid in fat loss) and catecholamine levels (which are chemicals your body produces to mobilize fat stores for burning).
Post-exercise appetite suppression.
So there you have it.
There are a multitude of ways you can manipulate your rest:work ratios. At Spectrum, we typically employ a 3:1 ratio. For example, if we put you on the bike at the end of your workout (intervals should always be done after resistance training), we would have you pedal at a pretty easy pace for the first 45 seconds. It should be comfortable to talk at this point.
The last 15 seconds of every minute is where you make your money and where the real fun begins (insert sarcasm here).
Pedal as hard as you absolutely can. There’s no doubt about it, you will need to put your big girl pants on and dig deep mentally and physically. This is taking all of your effort to get through and you should feel like you’re in hell for that godforsaken short period of time. Any Spectrum client should be able to attest to this.
As an additional side note, here at Spectrum we only have 3 stationary bikes and 1 elliptical. That’s because these machines are very low impact and will not place stress on your joints. They will pose plenty of a challenge so long as the intensity level and the duration meet your individual ability levels. If you’re confused on how to find this perfect harmony, this is where you should seek the advice of a fitness professional.
If you genuinely enjoy these steady, lower-intensity activities, then by all means continue on. If you want some fresh air, take in the scenery around you, or clear your mind after a crazy day of work or being stuck inside taking care of the kids all day, it’s certainly better than no exercise at all and there are still great benefits.
But if your reasoning is because you think it’s what’s most effective in torching undesired body fat, it simply isn’t true and this blog post was meant for you. You burn far more total calories (including calories from fat) at higher intensities than you do at lower intensities.
I hope this proves to be useful and as always, I’m willing to answer any questions you may have!