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Maximizing Fat Burn: The Science Behind Cardio and Heart Rate for Weight Loss

Weight loss is not as complicated as you may think. The truth is, it takes a lot less physical exertion and a lot more food control to reach an ideal body weight. It can feel intimidating to start an exercise program when you envision CrossFit games, marathon runners, and bikini competitors and the workouts they must do to gain such impressive physiques.

You may be relieved to hear, none of those intense workouts are necessarily required to start losing unwanted body fat and feeling good.

There are a few formulas you can follow and we share them here. But first, it will help if you understand a little more about what you need to accomplish with your heart rate during exercise to burn body fat and boost your metabolism.


Exercising to lose weight comes down to calories. How many calories you eat and drink in a day, against how many calories you use for energy in a day. Exercise helps you use more calories.

A great way to start your weight loss program is to add daily movement. Cardio exercises usually come to mind. I agree with that up to a point. But more specifically, I agree the main objective to exercise should be getting a high calorie burn during your sessions - regardless of strength training or otherwise. This helps create the calorie deficit needed to lose body fat.

High Calorie burns can be achieved in multiple ways and not only by running endless miles or participating in aggressive boot camps.

You can do those things, if you enjoy them. But it isn't mandatory.

Your goal at each session should be to get your heart rate up into your "fat burning zone" and then come in and out of your cardio zone.  This number is different for each of us. It's a calculation used primarily with someone's age.

To calculate your fat burning zone, use the following equation:

220 (- minus) your age / Divide that number in half / Add 50 to that number

So, by these calculations, my prime fat burning zone is 136.5

220 - 47 = 173

173 / 2 = 86.5

86.5 + 50 = 136.5

You want to stay within 10 in either direction of your fat burning zone. I strongly recommend investing in a heart rate monitoring system and wear it whenever you exercise. This is the best way to know how your heart rate is responding to exercise.


What level of intensity is required to lose body fat?

When you exercise in your cardio zone primarily, you burn more glycogen, or stored carbohydrates as your main energy source, using less fat.

So, if your heart rate stays elevated to high for to long, you won't use much body fat for your workout. Also, it can be hard on your heart and just plain uncomfortable to maintain such a high heart rate.

However, using some of your cardio range helps your total caloric burn be much greater. Remember, calories burned is what results in weight loss.

Strategy: Pop into your cardio range briefly and then take a short break or slow your pace - allowing your heart rate to go back into fat burning. This cycle can be repeated throughout your session.
  • If you are just beginning, staying at the low end of your fat burning zone is fine. Bump it up as you feel improvement in your endurance. You are making a difference and you are getting benefits.

  • If you are in average or even athletic shape, aim for the high end of your fat burning zone. Push to move up into your cardio zone during sets or bouts. Start your next set of exercises when you get back to your median range. Try not to let your heart rate drop below your low end with extended breaks.


The good news is you really do not need to wipe yourself out to achieve substantial weight loss. Here are some workouts you can try to maximize your goals.

The Treadmill

Go for time, not distance.

First Lap: Slowly increase the incline to the maximum you can handle until you get half way through the first lap. Finish the last half at that incline. Speed does not matter.

Second Lap: Lower the treadmill belt to 0 incline. Speed walk or even jog that entire lap.

REPEAT this for 45 minutes

Strength Trainers (my personal favorite)

Go for calories, not for the workout.

Rather than going to the gym with a workout to complete, have the mindset not to leave until you hit a predetermined calorie goal. I recommend women 400 - 600 and men 700 - 900.

You want to watch your heart rate and break times. Depending on the weight and exercises, your break times will vary to achieve maximum fat loss. You complete all of your strength training exercises first. Once you are done, you may need some cardio to reach your goal - but you cannot leave the gym until the combined workouts hit it.

The Walker

Go for heart rate zone, not distance.

Start by doing a 30 second / 30 second split. Walk at a fast pace for 30 seconds and then slow to a normal pace for 30. You will find it is easier to get into your fat burning zone than you thought. This is a great place to challenge yourself to eventually pop up into cardio. For now, challenge yourself to stay in fat burning.

The Runner

Go for heart rate zone, not distance.

Do a warm up to make sure you are safely into your fat burning range. Jog for 30 seconds and then speed walk for 60 seconds. This timing may vary. But the idea is to slow down and stay closely in between fat burning and cardio for at least 45 minutes. You can also add things in like lunges and jump squats to help hit that cardio benchmark

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