CONQUERING CARDIO: The truth about the fat-burning zone and what works best!

By Lindy Olsen

We’ve all seen them; the people who are in the gym day in day out, month after month, making little progress in the fight against body fat. Fat burning can be a complex issue for many people. Initially body fat seems easy to shed if you increase your aerobic activity a little more than normal. However, what do you do when you’ve made some progress, but can’t get to the next level? We’ve all seen incredibly skinny people spending two hours doing cardio, yet they have no shape or tone.

Most people ask me, “when is the BEST time to do cardio?” Basically, there is NO ideal time to engage in aerobic or cardiovascular training. However, the ideal program is one that you will enjoy, as you’ll be much less likely to avoid it when there’s something more interesting to do. Many fitness professionals (including me) suggest doing cardio first thing in the morning before your first meal. The advantage of  performing cardiovascular exercise in the morning is that it helps burn off fat stored overnight and helps kickstart your metabolism for the rest of the day. Cardio uses body fat as fuel and the amount of carbohydrate in the bloodstream influences your body’s ability to maximise fat burning. If there are a lot of carbs in your bloodstream from a recent meal, then fat burning decreases. If there are minimal carbs in your blood, fat burning skyrockets.  That’s what makes cardio in the morning on an empty stomach so effective. Having no carbs in the blood, especially after an overnight fast, elevates your ability to melt away body fat. Alternatively, working out later in the day burns off the calories you’ve consumed in your meals, and can be used as a form of stress release for many people.

Remember: fats can only burn in a carbohydrate flame. If you have no carbs in your system at all (they are stored in your muscles as glycogen), as opposed to just having them in your bloodstream, then you will be burning protein and breaking down muscles – not good !

“Your results are usually a direct reflection of two things - consistency and commitment.”


Your results are usually a direct reflection of two things - consistency and commitment. Nothing less will ever get you any real results. For many people, cardiovascular training on a treadmill is much more enjoyable when watching a TV program or movie. If time goes by quickly, your workout is over before you even realise you’re raising a sweat! Just make sure your cardio workout keeps you at your target heart rate for at least 20 minutes, three times per week, for general health. If your goal is to lose body fat, try to work out aerobically for at least 30-45 minutes, four times a week.

New research shows that fat burning can be enhanced even further if you take amino acids before your cardio workout. The general recommendation is to go with 3-6g of an amino acid product which contains: alanine, arginine, cysteine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine and valine. The best two I’ve found are Musashi’s ‘Disperse’ (a liver tonic and fat burner) and L-Carnitine. I ingest these pure aminos before EVERY workout - rain, hail, or shine! L-Carnitine helps to convert your body’s fat reserves into energy for use during your workout. Take these 20 minutes before you start exercise and you’re set to go!! Another option is to go with 10-20g of pure whey protein isolate or hydrolysate. Just be sure the product contains no additional carbs or fat.


To figure out which zone you need to work at to burn the most fat (rather than your precious muscle tissue), you first need to find your target heart rate. There are several ways of doing this. One of the best methods I use is the Karvonen formula. You can use any number of target heart rate calculators to get your heart rate zone, but many of them do not take into consideration your resting heart rate (which makes the calculation more accurate). Follow the example below for a 33-year-old individual with a resting heart rate of 65 beats per minute (to work out your resting heart rate, take your pulse for one full minute).

220 - 33 (age) = 187
187 - 65 (resting heart rate or RHR) = 122 (your heart rate ‘reserve’, or what you have to work with)
122 x 65% (low end of heart rate) OR 85% (high end) = 79.3 OR 103.7
79.3 (low end) + 65 (RHR) = 144.3
103.7 (high end) + 65 (RHR) = 168.7

Therefore, the 65-85% target heart rate zone for our person above would be 144 to 168 beats per minute (bpm).

For this person to make sure they were in the ideal ‘fat-burning’ zone, they would need to try to sit around 144bpm or lower. However, if our case study wanted to work in the ‘cardio’ zone, she would have to stay around 144bpm or higher.

Don’t get me wrong, you are still burning fat while working out at a ‘cardio’ heart rate, but in different percentages. This is a huge misconception in the fitness industry. Now listen up and you’ll get the correct information, right from the horse’s mouth! Low-intensity exercise burns a higher PERCENTAGE of fat calories than high-intensity exercise – but high-intensity exercise burns MORE fat calories and MORE total calories done over the same time period. Let me explain. Let’s say you walk for one hour and burn approximately 250 TOTAL calories. At this level of exertion you are burning around 70% of your calories in fat. Now, 70% of 250 = 175. So you have burned 175 FAT calories.