By Elena Voropay

Let's get straight to the point - losing weight is all about expending more calories than you consume throughout the day. It is well known that this may be achieved by eating well and exercising, but it is not commonly understood which exercise program is the best for burning the most calories in a day. The two main programs to discuss are aerobic, or cardio, and resistance, or strength training. Each program acts on your body in a different way, so they should be examined separately to determine which is best for promoting weight loss.

An aerobic program usually consists of cardiovascular exercise performed three to six days per week. Assuming each session lasts 30 minutes, the caloric expenditure is anywhere from 300 to 500 calories per 30-minute session, depending on intensity. 

Fit and Toned Body

Now, compare a cardio session to a resistance training session of equal duration. The resistance training session will burn roughly half the calories of the cardio session. The main reason for this is that during the cardio session your heart and your muscles are working continuously for 30 minutes. In a strength training session, after you take away the rest between sets and the rest between muscles worked, you are really only working for about 10 minutes.

Which One?

So, does this mean that a session of cardio causes greater energy expenditure than a resistance training session of equal duration? Yes, however there are other factors to consider which influence your caloric expenditure for the rest of the day after you have finished exercising.

Resting metabolic rate (RMR) is a term that is used often, but is not always understood. RMR is the minimum number of calories, or energy, required to fuel the vital functions required for life. These vital functions include things like breathing, circulating blood and mental function. When you exercise, your RMR increases due to chemical and hormonal changes and it stays elevated for quite some time after you exercise.

After a cardio session your RMR remains elevated for roughly two to three hours; however, the RMR has been reported to remain elevated for 10 to 15 hours after a resistance training session. After following a resistance training program for some time, your daily RMR may also increase as you build more muscle. Muscle is more metabolically active than fat, so individuals with more muscle mass usually have a higher resting metabolic rate. The average female’s metabolic rate is roughly 5 to 10% lower than an average male of the same size simply because of females’ genetic predisposition to having less muscle mass.

As you can see, while a cardio program provides an immediate higher caloric expenditure, a resistance training program provides a caloric expenditure of the same magnitude, but spaced over a longer period of time. So, the answer to the commonly asked question “Which program is better for losing weight” is simple: follow a program that includes a combination of both strength and cardio training. This way you will receive all of the short-term and long-term benefits of exercising.

The Best Time To Burn

It's essential if you are going to optimize fat loss, that you perform your aerobic exercise AFTER your resistance training. Here's why. When you are in an aerobic state, which means you're meeting momentary oxygen demand (as you would if you were to walk, job, or climb stairs) your body has two options for fuel. It can burn fat and/or it can burn sugar (glucose, stored in the muscles and the liver as glycogen). When you perform anaerobic exercise, which is a short term all out burst of energy (as in each set of your resistance exercise), your body burns exclusively glucose (sugar). If you were to do an exhaustive aerobic exercise workout before weight training, you would burn stored glycogen. If you deplete glycogen stores, your fuel reserve will be limited for your weight training session. In order to supply fuel, your body might opt to break apart muscle to convert amino acids into glucose, and as you already know, a loss of muscle is to be avoided at all costs. If you do your aerobic exercise AFTER your resistance training, you can utilize glycogen for the weights, and then tap into fat stores to fuel your cardio. Muscle tissue remains intact.

Cardio - How Hard Should You Work

The good news is if you are willing to commit to 20 to 35 minutes of cardiovascular activity most days of the week, the excess fat will begin to melt off. But to optimize your caloric expenditure and fat burn, you will need to surpass the fat-burning zone.

What's the fat-burning zone? Exercising in the fat-burning zone requires you to keep your heart rate within 60 to 70% of your age-predicted maximum heart rate. Many cardiovascular machines allow you to choose the fat -burning zone as a setting. These settings generally keep the intensity low so that a higher percentage of fat is burned. Unfortunately, a higher percentage of fat does not mean more calories. If you cycle for 30 minutes at a low (fat-burning) intensity and at a high intensity he/she will burn different percentage of calories and fat in each session. Interestingly, the higher the intensity, the more calories are burned, but the less fat is used. The lesser intensity needs less calories overall but uses more fat.Precisely, cycling for 30 minutes at low intensity of 60 to 65% maximum heart rate will burn a total of 204 calories with 55 percent of these, namely 112 calories, coming directly from your adipose tissue (or fat). But once you stop cycling, the fat loss stops and in a couple of hours your metabolic rate will return to previous.

Add the intensity to 80 to 85% and you will use 340 calories in half an hour session, but burning only 35 percent or 119 calories as fat. However, your metabolism will remain elevated for a lot longer and will will continue burning fat throughout the day. If you cycle at high intensity on a regular basis, you will permanently increase your metabolism and start burning more calories and fat overall. Since losing weight is only achieved by burning more calories than you expend, high intensity aerobic training is more beneficial to achieving a fat loss goal. However, consistently exercising at a high intensity can cause mental and physical burnout along with injury.

The application of all of the above information to your case is simple. There really is a fat-burning zone and you can find it for yourself. First, subtract your age from 220 and multiply the result first by 65%, then by 85%. The resultant two numbers would equate to the low and the high ends of your Target Zone which is measured in heartbeats per minute. When you are near the lower end of the "zone," you will burn proportionately more fat, however, when you are nearer to the higher end, you will burn greater volume of calories.

Your best approach is to follow an exercise program that offers both low intensity and high intensity days. This will keep you motivated and allow your body to recover between sessions. For the utmost results your body demands follow the strategy of alternation. Day #1 might be a low intensity longer duration session. Day #2 might be a high intensity shorter duration session. Day #3 might incorporate interval training where you shift the intensity throughout the session for a moderate duration. Then you return to Day #1 and the process repeats. One tip I share with my clients is to exercise at a higher intensity level when performing activities you enjoy. For instance, if you love cross-training, save your cross-training sessions for the high intensity days and run during your low intensity days. However, keep in mind that a moderate intensity level is also very beneficial. Exercising at an intensity level equivalent to 65% to 85% of your age-predicted maximum heart rate will help you burn fat and achieve wonderful health benefits.

Consistently training at a low intensity level, such as the fat-burning zone, is recommended for those who cannot tolerate high intensity exercise. If you are new to exercise, or have a medical condition that limits the intensity of exercise you perform, low intensity exercise is a must. However, if you are able to exercise at a higher intensity you will burn more calories and lose more fat. The secret is to burn more calories than you consume. A weight loss program that helps you achieve caloric, pH and hormonal balance will also help you shed pounds.

Remember, every little bit of activity helps, so never neglect an opportunity to move your body and burn some calories.