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I’d be willing to bet you’ve spent hours working out in it.  At one time or another it may even have been the basis of your overall weight loss strategy.

It’s the cardio ‘fat burning zone’ whose graphic representation has a prominent spot on the consoles of many cardio machines at the gym.  It’s a magical place between 55% and 65% of your maximum heart rate where fat burning potential is said to be optimal.  According to the theory, above this level you’re reaping more cardiovascular than fat burning benefits.

Does the ‘fat burning zone’ really exist?  It’d sure be nice if it did.  Workouts in the ‘fat burning zone’ really feel quite comfortable and aren’t difficult to sustain for an hour at a time.  These are your brisk treadmill walks with 2% incline, or a medium pace on the elliptical with no resistance.  It’s arriving to the gym believing that if you can do an easy hour of cardio while watching TV, you’re on your way to fast fat loss.

Unfortunately the ‘fat burning zone’ is very misleading.  It’s left many women confused, wondering why, despite hours at the gym per week, they’re not shedding the pounds.  Let’s take a look at the theory behind the ‘fat burning zone’ and bust this pervasive fitness myth once and for all!

The Fat Burning Zone Theory

Source: Reebok heart rate chart

Well, the cardio machines aren’t completely lying to you…they’re just not telling you the whole truth.  Scientifically, it is true that when you work at about 55% to 65% of your maximum heart rate, a higher percentage of the overall calories burned come from fat.

However, if you work out at a higher percentage of your maximum heart rate for the same amount of time, let’s say 80 – 85% of max,  you’ll burn more overall calories and thus more fat calories, too.

The chart below demonstrates that you burn an overall higher amount of calories from fat by exercising at a higher intensity for the same amount of time.

The chart below details the fat calories expended by a 130-pound woman during cardio exercise:

 Source: From The 24/5 Complete Personal Training Manual, 24 Hour Fitness, 2000 via About.com

The BEST Cardio to Burn Fat…

So, I’m sure you’re thinking, “Great…I’ll do the same cardio I’ve been doing at a higher heart rate and I’ll burn more fat overall.”  Not so fast….

Steady state cardio at any level is not the best strategy for fat loss.  When it comes to cardio, short intense bursts are best.  We’re talking about short HIIT (high intensity interval training) workouts or sprints.

While the effort required for a short intense burst will feel tougher, you’ll burn more calories (and thus more overall calories from fat) in a much shorter period of time.  Not only will you burn more calories during your workout, at higher intensities you can benefit from the afterburn effect, in which you continue to burn calories even after your workout is over!

While higher intensity steady-state cardio (in the 80 – 85% of max heart rate zone) can elicit some afterburn, studies have shown that HIIT type workouts are even more effective for creating post-workout calorie burn.

One More Reason to Quit the Chronic Cardio

Still tempted to stick with your hour-long treadmill sessions or group exercise cardio classes?  There’s one more important reason why short intense bursts are better.  Aside from saving yourself a ton of time, you’ll also be saving yourself from overtraining injuries.

Long drawn out cardio, especially hour after hour of it every week, takes a huge toll on the joints.  If you’re doing impact cardio many hours per week in the ‘fat burning zone’ (or at any heart rate for that matter) including stuff like running, step aerobics, cardio kick boxing, cardio dance, etc., you are at risk for overtraining, including joint problems and stress fractures.

Now that we’ve covered cardio, it’s time to talk about the most important fitness factor for weight loss.  It can save you a lot of time and energy, and get you better results in a shorter amount of time than cardio will.

Don’t Neglect This One Thing for Fat Burning!

If you really want to blast fat, improve your metabolism and get a toned athletic shape, it’s time to swap out about 80% of those cardio workouts for something better: circuit strength training.  We’re not talking about lazy weight sessions on those medieval looking machines at the gym.

We’re talking about alternating tough, effective strength training and bodyweight exercises at an intense pace with no breaks.  It maximizes your time and your results because the combo of tough exercises with no rest helps you get your heart rate up as high as cardio does while you get your strength training done at the same time!

That’s not all.  The muscle tone you build with strength training gives you something even better than afterburn.  Muscle burns calories all day long, and even while you sleep…not just within the first few hours after your workout.

Finally, muscle also gives you a toned, shapely look that cardio exercise alone can’t achieve.  It’s that sexy athletic look that we’re all really after, but just haven’t known how to get…up until now!

So, how can you get started with the right type of workouts to maximize fat burning?  Consider giving Athlean-XX for Women a try. Our circuit strength workouts are just 30 minutes long.  They’ll ensure you get the best results possible in the shortest amount of time without risking overtraining.

The plan is flexible.  You can work out at home with our DVDs or at the gym with our workout cards.  There are 3 workouts per muscle group and advanced modifications so that you can continue to challenge yourself.  If you like, you can incorporate one to two days of HIIT or high intensity cardio into the plan, but it’s not necessary to achieve great results!

There’s also a super flexible meal plan.  Follow our 90 day plan exactly, mix and match meals and days or make up your own meals from our lists of healthy foods.

If all that cardio still hasn’t gotten you the body you’ve been wanting, join the ladies on Team Athlean!  You’ll be amazed what you can accomplish in just 90 days.