THE CARDIO MYTH: WHY AEROBIC EXERCISE IS NOT GREAT FOR FAT BURNING

By Josh Olney

It is commonly believed that to burn fat and get into great shape a person needs to run or jog for long periods of time or cover great distances performing other aerobic activities such as cycling or hammering the x-trainer. It is often thought that long, gruelling cardiovascular workouts burn huge amounts of calories and, therefore, must result in significant fat loss. In reality, this is a common misconception and is simply not true.

The human body adapts very quickly to long, steady paced cardio workouts and so if this sort of exercise is repeated regularly, then you will actually burn less calories every time you workout on the x-trainer or go road running. This is because if, for example, you ran consistently over the same distance, at a similar steady pace, your body would become efficient at performing that particular type of workout. Therefore, it becomes easier to perform that workout and so less energy expenditure is required. In fact, research has shown that too much long distance, 'slow and steady' aerobic exercise can break down muscle mass. This is significant because having lean muscle on your body increases your metabolic rate (the rate at which you burn calories) and so when you lose lean muscle your metabolism will actually slow, and you will burn less calories!

It is another misconception that aerobic forms of cardio exercise raise or have an effect on your resting metabolism. In actual fact, you are generally only burning calories for the period of time you are aerobically exercising. So, whatever you consume immediately after exercise, such as a sports drink, will often cancel out the calories you have just burned.

Longer runs are definitely not better for fat burning. Think of it this way: You may decide to significantly increase the distance you cover, believing this will burn more fat. But, your exercise intensity over this distance will, inevitably, decrease. This reduction in intensity will reduce the effectiveness of your workout as you will burn fewer calories from fat. When it comes to fat burning, long distance cardiovascular exercise is extremely inefficient and is a waste of valuable time. If your goal is to be able to run a marathon then cardio is great, but to burn fat there are far more efficient ways.

So, if cardio isn't great for fat burning, then what is? The answer to this is weight or resistance training. In contrast to the effects of low to moderate intensity cardio exercise, weight training actually significantly boosts your metabolism after exercise. Research studies have found that weight or resistance training significantly increases a person's metabolism for up to 38 hours post workout. Even better news is that for every pound of muscle a person holds on their body they will burn an extra 50-100 calories per day, simply doing nothing. This figure rises to an average of 120 calories a day for every 3 pounds of muscle. This is hugely significant when you consider that a pound of fat is equal to 3500 calories. To burn 3500 calories via running or jogging etc would mean hours and hours of hard, boring work, and after all that work you would probably also have ended up burning muscle mass, resulting in a slower metabolism, as I mentioned earlier.

I would also like to mention two further myths surrounding these topics. The first is in case there are any women reading this thinking it doesn't apply to them. I have encountered many women who want to avoid resistance or weight training as they believe this would lead to them looking like a bulky female bodybuilder. This is not the case. Ninety-nine percent of the time, women simply do not have the testosterone to achieve extreme hypertrophy. Men find it hard enough to bulk up! And so the concepts discussed in this article most definitely do apply to women as well. Secondly, it does not take 1000 abdominal crunches or sit-ups a day to achieve a toned or 'six-pack' stomach. Everybody has a 'six-pack'; it is just hidden under layers of abdominal fat in most people. Genetics play a major role in deciding how chiselled a persons stomach may or may not be, but a six-pack is there! Crunches won't burn the fat on your stomach in the way that weight training will. When I say weight training I generally mean weights programmes designed around compound lifts, such as squats and deadlifts, which work large muscle groups. These types of exercises will also stimulate your core abdominal muscles and so when the fat has disappeared a toned stomach will be left underneath.

A study from Canada in 2007 by McMaster University's kinesiology department found that aside from strength and bone density gains, weight training also reduces the risk of diabetes and cardiovascular disease. This was because weight training may significantly lower unhealthy cholesterol levels and tryglyceride (causes of heart disease) and the increase in muscle mass promotes fat loss and lowers blood glucose, which both cause diabetes.

Further research studies have been conducted looking in to the fat burning effects of diet regimes, diet plus cardio regimes, and diet plus cardio plus weight training regimes. It has been found that groups who combined weight training with the other two factors lost the most fat. Even more significant is the finding that groups combining cardio exercise with diet regimes lost hardly any more fat than those groups controlling their diet alone.

Some further benefits of weight bearing activity or exercise include increased bone density, increased ligament and joint strength, thicker articular cartilage, increased muscle tone and increases in gains in muscular strength and size.

So, we have established that weight training is in fact very good when it comes to fat burning, and long distance cardio is not. However, this does not mean that all cardio exercise has no benefit and is bad for you. There are many positive effects on the body resulting from cardio forms of exercise. Just some of these include a reduction in resting heart and breathing rates, a possible reduction in blood pressure, increased recovery after exercise, increased heart size, increased efficiency of lungs and an increased efficiency of blood distribution during exercise. All of these benefits will actually aid a person in their weight lifting exercises. This is because as the cardiovascular and respiratory systems become more efficient, blood and nutrients can be distributed to the muscles more quickly. So, cardiovascular exercise does have many benefits. But it is important to understand what types of cardio exercise a person should be doing, including the intensity and duration.

It is entirely possible to achieve your fat burning goals through a controlled diet and weight training alone. However, if you wish to include additional cardio forms of exercise to maximise fat burning potential then I will explain some effective techniques to try.

Firstly, do weights before cardio. A hugely common mistake people make is to spend a long period of time doing cardio and then do little or no resistance training. The reason for doing weights first is simple. In order to burn fat, you must first use up your glycogen stores. Glycogen stores come from carbohydrates. Carbs (basically sugars and starches) break down into glucose molecules which are used as energy to fuel your brain and muscles. If the body doesn't have a use for this glucose it is stored as glycogen in the muscles and liver as an energy reserve. If a person ran, for example, for twenty minutes, they might spend fifteen minutes using up these glycogen stores and may only actually be burning fat for five minutes. The best way to use up glycogen stores is through weight training. Therefore, if you start with the resistance or weights part of an exercise programme then when it comes to the cardio phase you will maximise the fat burning effects as you use fat, not glycogen, to fuel the exercise.

So overall, a person will make the most strength, toning or muscle gains AND burn the most fat by doing weights before cardio.

The idea of doing weights before cardio is supported by a study at Southern Cross University, Australia (2000), which found that men who exercised on a stationary bike for 30 minutes were weaker for up to six hours after that training session had finished. This shows the negative effect of cardio before weights and it has also been found that strength decreases over time when consistently training in this way. Why would anyone want to jeopardise their muscular strength and endurance gains when we know the fat burning potential of weight training regimes?

One of the best types of cardio exercise you can do to burn fat is high intensity interval training (HIIT). Interval training involves changing the speed and intensity at specific points in a workout. It is fast and extremely tough, often involving periods of maximum effort, such as sprints, and is very effective. Research has shown that interval training burns up to nine times more fat cells than long, steady paced cardio workouts. In addition, research from Laval University in Quebec found men who exercised at a high intensity lost three times more fat than those who did low intensity exercise, even though the low intensity group exercised for longer and burned over twice as many calories. So, keep the duration short, up to thirty minutes, and keep the intensity high. Ideally, perform interval training.

An example of a high intensity interval training workout would be as follows:

5 min warm up

15-30 sec sprints (max effort) x 10 30-45 sec recovery periods x 10 (i.e. - sprint for 15 secs and then slow to a recovery pace for 45 secs)

5 min cool down

This should take no more than 20-25 minutes and could be performed on a machine such as the x-trainer or rower, or performed running outside, for example, in the park or up a hill (hill sprints!).

So, in summary, to burn fat, train with weights and perform shorter, higher intensity cardio workouts such as high intensity interval training. Do not rely on long, slow, steady paced cardio routines.