You may be familiar with the talk test, which assumes you are exercising within the aerobic range if you can comfortably talk to your exercise partners during a workout. This test is unreliable and in fact often maintains someone in an mild anaerobic state.

The 220 Formula, unfortunately still widely used today, has you subtract your age from 220 and multiply the difference by a figure, ranging from 65 to 85 percent. The resulting number supposedly provides you with the training hearth rate. This formula contains two serious errors. It assumes that 220 minus your age is your maximum heart rate. In reality, most people who obtain their maximum heart rate by pushing themselves to exhaustion (We don't recommend you do this) will find it's probably not 220 minus their age. About a third find their maximum is above, a third will be below and only a third may be close to 220 minus their age.

Calculating your maximum aerobic heart rate

1. Subtract your age from 180 (180-age)
2. Modify this number by selecting one of the following categories:

1. If you have, or are recovering from, a major illness (heart disease, any operation, any hospital stay, etc.) or if you are on any regular medication, subtract 10.

2. If you have not exercised before, or if you have been exercising but have been injured or are regressing in your efforts (not showing much improvement), or if you often get colds or flu, or have allergies, subtract 5.

3. If you have been exercising for up to two years at least four times a week without any injury, and if you have not had colds or flu more than once or twice a year, subtract 0.

4. If you have been exercising for more than two years without any injury, have made progress, and are a competitive athlete, add 5.

For example, if you are 30 years old and fit into Category b:
180 - 30 = 150, then 150 - 5 = 145 beats per minute.

This is called your maximum aerobic exercise heart rate. In this example, exercising at a heart rate of 145 beats per minute will be highly aerobic, allowing you to develop maximum aerobic function. Exercising at heart rates above this level will add a significant anaerobic component to the workout, and develop your anaerobic system, exemplified by a shift to more sugar burning and less fat-burning. If you prefer to exercise below your max aerobic heart rate, you will still derive good aerobic benefits, but progress at a slightly slower pace.

The only exceptions for this formula are for people over the age of 65, and those under the age of 16.

• For the seniors in category c or d, you may have to add up to 10 beats after obtaining your maximum aerobic heart rate. That doesn't mean you must add 10 beats. This is such an individualized category; getting assistance from a professional would be very helpful.

• For kids under the age of 16, there's no need to use the 180 Formula. Instead use 165 as the maximum aerobic heart rate. Ideally, kids can be very intuitive, and may not even need heart monitors. Unfortunately, most have already been influenced by the no-pain, no gain work ethic in sports. If this is the case, a monitor will help them.

When you first exercise at your maximum aerobic heart rate, it may seem too easy. Many people have told me initially they can't imagine it's worth the time. I tell them to not only imagine it will help, but to understand how the body really works.

In a short time, exercise will become more enjoyable, and you'll find more work is needed to maintain your heart rate. In other words, as your aerobic system builds up, you'll need to walk, ride or dance faster to attain your maximum aerobic heart rate. If you're a runner, your minute-per-mile pace will get faster, bikers will ride at higher miles per hour at the same heart rate and so on.

Once you find your maximum aerobic heart rate, you can conveniently make a range that's 10 beats below that number. Most heart-rate monitors can be set for your range, providing you with an audible indication if your heart rate goes over or under your preset levels. Set yours at the maximum aerobic rate you determined. Most monitors also provide for a low setting, which could be 10 below the high. This gives you a comfortable range to work out in. For example, if your max aerobic heart rate us 145, then the low would be 135; set the monitor for a range between 135 - 145.

It's not absolutely necessary to work out in your range. You just don't want to exceed it. If you're more comfortable under that range, you will still derive good aerobic benefits.