How many minutes of cardio in order to burn fat?

Q: I have a few questions about cardio. I have always heard that you have to do 20 to 30 minutes of cardio before your body begins to burn fat, and anything less is a waste of time. Is this true? Do I have to do a certain time period before I can get progress? - Ben

A: This is far from true. In fact, more is not always better when it comes to getting in shape.

To illustrate this point let me tell you a little story: A few years ago a woman signed up to train with me because she had hit a plateau and just wasn’t making progress.

When she started working out a month earlier, she lost 10 pounds, but by the time I met her, she was stuck in a rut. She had increased her cardio sessions to 45 minutes and did them five times a week without any more results.

After I looked over her program, the answer was clear: Although she had increased the time, she had not once increased the intensity. The workout had become easy for her, and although she was still burning calories, her body refused to release fat because it had adapted to the workload. The solution was to simply cut back the time and increase the intensity until the cardio became challenging again. Guess what?

She quickly lost 10 pounds, and she did it starting with only three sessions of 15 minutes.

As time passed and she continued to get in better shape, we added time to her sessions as well as a variety of different changes to keep the body guessing, but the key was her work-outs never again became easy. She was permanently out of the comfort zone, but the results were well worth the work.

Cardio programs vs. fat-burning
What is the difference between doing the fat-burning program on the cardio machines at the gym and the cardiovascular program?

Programs on machines can be very misleading. The fat-burning program is supposed to work at a slower, more comfortable pace and burn a larger percentage of fat, while sparing muscle mass. The cardio program works at a higher level and faster pace, with the goal of increasing endurance of the heart and lungs.

The problem is what is hard for one person may be easy for another and vice versa. That’s why I never use a cookie- cutter program to decide what type of workout my clients are going to do. We start with the manual program to find a level and speed that is challenging and then increase the intensity as needed.

Target heart rates
Do you have to keep your heart rate in the target heart-rate zone even though it now seems easy?

Before I answer this question, let me first explain what the target heart rate is and why it’s important.

Your target heart rate is the speed at which your heart beats when you’re working hard enough to efficiently burn fat. You can figure out your target heart rate by subtracting your age from 220 and multiplying the answer by 0.75. For example, if you are 40 years old, your target heart rate would be 135 beats per minute: 220-40=180 x 0.75=135.

For the average 40-year-old, keeping the heart rate around 135 beats per minute when doing cardio is a good place to start. However, as you get in shape, your heart rate will begin to drop, and you’ll have to give it a new challenge to get it back in the zone again.

Athletes and people who are in good shape may find it difficult to stay in the target heart-rate zone, because their hearts can handle hard work without getting that excited.

People with medical issues should consult a doctor before starting a cardiovascular training program.

Remember: It’s important to be mindful that the body responds to changes. Learn to throw it a curveball every now and again to keep it guessing.