Before we begin to talk about the optimum intensity level, let me debunk one of the greatest myths out there.

It's all to do with the so-called 'fat burning zone'. The fat burning zone is a range that your heart rate has to be in, that apparently maximizes fat loss. Then there's also the 'aerobic zone' which is a more intense level than the 'fat burning zone' (which means you work harder during the exercise). Apparently if you are trying to maximize fat loss, you should be careful not to exercise too hard because if you raise your heart level to the 'aerobic zone' then you won't burn as much fat.

I can tell you categorically that this is just plain garbage.

To understand why, you first have to understand that all aerobic activity is fueled by a mixture of carbs and fats. And yes, at the so-called 'fat burning zone', out of the calories you burn, there's a greater percentage burned from fat than from carbs. And it's also true that if you exercise in the 'aerobic zone' then of the calories you burn, you burn a greater percentage from carbs than from fat.

But what they don't tell you is, that if you work harder you burn a heck of a lot more calories from both fats and from carbs. So who cares what percentage of that is fat and what percentage of that is carbs, you want to burn the most total number of calories from fat (not the highest percentage calories).

So don't ever be worried about working in the 'fat burning zone'.

In fact you don't ever have to worry about heart rate zones, and what your heart rate is. It's very difficult to work out your maximum heart rate zone practically. Yes, there are approximations and formulas, but these are not that accurate, because everyone is different.

A common formula used to work out your Maximum Heart Rate is :

Maximum Heart Rate = 220 - Age

Then all of these zones are based on this calculation. The only problem is this is an approximation. A cardiologist told me that this is used by most as a starting point for tests on their patients, but is only 95% accurate. Does that sound accurate?

If you think about it, it's not really. Because it means its wrong for 5 people out of 100. That's a lot of people, especially if you are one of those 5. That's why cardiologists use this as a starting point, and do much more intensive tests to get a real picture of their patient's heart and well being.

So if this is so inaccurate, why bother with buying heart rate monitors and so on. There's no point is there? You can use an alternative instead. And it's a whole lot more convenient.

And that's using what's called 'perceived exertion'. It sounds complicated, but it isn't. All perceived exertion is a subjective rating you give to your own workout between 0 and 10.

A rating of 0 would be if you are lying down or sitting down, and a rating of 10 is when you are going full out, where you can hardly breathe.

So for each exercise you give it a rating depending on how much intensity you feel you have 'spent'.

It's just giving your workout a rating. You definitely want to record this rating along with the length of time you spent exercising and also the exercise you did.

It's subjective, but overtime you can measure your progress in this way. The great thing about this is that as your aerobic capacity improves, your workouts will get more intense automatically. This is because what was previously a 5 workout may be now a 3. So to work at the same intensity (a 5) you work harder, which offsets the fact that your body is more efficient at burning calories.

You therefore continue to burn the calories, and the fat continues to come off you. This way you're maximising the benefits from doing aerobic exercise.

Now, you may be wondering at what level you should be working out at.

The general rule is work as intensely as you can so that you can work out for at least 30 minutes consecutively. The reason is the harder you work, the more calories you burn. And that's your aim.

Ok, I know some of you want some detailed information on exercise programs:

As far as particular exercise programs go for controlled, long lasting weight loss, I recommend two programs.

Tom Venuto's "Burn The Fat" ebook is the first recommendation because apart from containing a great section on exercise (he's a natural bodybuilder and personal trainer), he also has the best overall book on weight loss - from the many I've reviewed.

If you're only interested in the exercise section, then I believe Craig Ballantyne's "Turbulence Training" is best for you. His nutrition package may not be as comprehensive as Tom's book, but his exercise section is just killer. It is the best one I've seen that's targeted for weight loss. He even covers bodyweight exercises in his course (which is using your own bodyweight to simulate weight training without the weights).