You know the basics about your exercise routine. You know how far you ran this week, and how fast, how much you sweated at that Pilates class on Monday, how you're planning to up the resistance on your elliptical at your next speed session tonight. You've got the commitment and you're feeling great about putting in the time to do something good for yourself.

But do you really know if your body's reaping the benefits of all these good intentions?

Many exercisers don't reach their goals. Often, they're exercising so hard they're risking injury and damaging muscle tissue, or they're not exercising hard enough, and wasting their workouts. Paying attention to your heart rate will help you tell the difference.

Using a heart rate monitor (HRM) to fine-tune your exercise and get fitter faster can be as beneficial as having your own personal coach at every session. According to Joe Friel, author of several bestselling exercise books and writer for fitness site Active.com, there are only three variables you can control when it comes to fitness: frequency (number of times you have a fitness session), duration (time you spend exercising), and most importantly, intensity, or how hard you're working out.

"These variables remain the same whether you want to lose a couple of pounds or train for the Olympics," Friel writes. "If you simply want to be healthy, a handful of easy workouts a week will do it, and you don't need a heart rate monitor to get this right."

But say you have some specific goals, like getting fit enough to run a local marathon for charity, or going faster at your yearly bike race out in Colorado, or just making sure you're getting enough intense exercise to result in weight loss. You need more information to make sure your body is gaining the maximum benefits in the minimum amount of time needed to improve, because who wants to waste a workout?

The Numbers on your HRM

The numbers on your HRM might seem confusing at first, but some basic facts about your body are all you need to begin reading your heart rate perfectly.

First, determine your Resting Heart Rate (RHR). Simply sit quietly for a few minutes, allowing your body to settle and your breathing to slow to steady intervals. Once you feel calm, set a timer or check a clock near you. As soon as it turns over a minute, begin counting your pulse for 15 seconds. (For information on how to get an accurate pulse, see WebMD's Pulse Measurement page.) The result you get after multiplying that number by four is your RHR.

Of course, you can also just use your HRM while sitting quietly for some time. That works, too.

Next, determine your heart rate zones. You can talk to your doctor to find out what these are, or you can use any of several high-quality heart rate zone calculators on the Web:

• WebMD Simplified Target Heart Rate Calculator (This calculator shows a general zone for aerobic fitness and maximum heart rate point only.)
• General Heart Rate Zone Calculator
• Runner's Heart Rate Zone Calculator

Most zone calculators, like the ones listed here, will divide your zones into "Easy," "Aerobic" and "Cardio" (or sometimes both, in one wide zone) and "Maximum" zones.

Depending on your goals, your HRM can let you know when your heart rate falls too low for that productive fat-burning session on the elliptical, when you've entered the cardio zone (which, in most cases, should be balanced in a reasonable ratio with the less intense aerobic zone) and warn you when you're approaching the "redline," reducing the risk of adverse health effects such as overuse or intensity injury.

In general, a good recommendation for beginners looking to improve their fitness and aerobic capacity is to target 50-70% of their maximum heart rate for a sustained period at least 20 minutes. The more experienced athletes can routinely achieve 70-80% of their maximum heart rate during exercise. The American Heart Association has more information about the relationship between the aerobic and cardio zones and weight loss. (To figure out what your optimum heart rate goal should be for exercise, talk to your doctor about your health and habits before starting a heart rate zone program.)

Over time, you will begin to equate your sense of the workout's intensity with your heart rate. When you feel you can exercise at higher intensities to achieve the same target heart rate, your fitness is improving. When that happens, you know — even before you see tangible results or reach the finish line — that you're getting fitter.

Using a HRM isn't the magic bullet to weight loss, and different sports require different combinations of heart rate zones in order to achieve the desired outcome, but no matter what you're training for — speed, endurance, your goal weight, or all three — using a HRM means getting fitter, faster.

This post was included in the latest edition of the blog carnival Staying Young - from the Inside Out.