YOUR TARGET HEART RATE
The use of heart rate monitors is much more prevalent in the last few years and heart monitors can be purchased with a multitude of bells and whistles. Used correctly a heart rate monitor can be your best training tool. However you MUST know your maximum heart rate and your correct training zones. There is a lot of misinformation on heart rate training. If you do plan to use a heart rate monitor take the time to become better educated.
The standard method to find max heart rate, used by many in the fitness industry (and posted on the wall at almost every gym) is probably the least accurate. It's a simple but unreliable method. Subtract your age from 220 to calculate your Maximum Heart Rate (mhr). If you are using this method you should just probably chunk your heart rate monitor in the trash can.
The Karvonen Formula is a little more accurate. You must know your resting heart rate to use this method and insert your training zone from below.
The most accurate method is to find your maximum heart rate or heart rate threshold through a stress test. This type of test is usually administered by a professional. You can also do a stress test on your own using these guidelines from heart rate training expert Sally Edwards.
Healthy Heart Zone (Warm up) --- 50 - 60% of maximum heart rate: The easiest zone and probably the best zone for people just starting a fitness program. It can also be used as a warm up for more serious walkers. This zone has been shown to help decrease body fat, blood pressure and cholesterol. It also decreases the risk of degenerative diseases and has a low risk of injury. 85% of calories burned in this zone are fats!
Fitness Zone (Fat Burning) --- 60 - 70% of maximum heart rate: This zone provides the same benefits as the healthy heart zone, but is more intense and burns more total calories. The percent of fat calories is still 85%.
Aerobic Zone (Endurance Training) --- 70 - 80% of maximum heart rate: The aerobic zone will improve your cardiovascular and respiratory system AND increase the size and strength of your heart. This is the preferred zone if you are training for an endurance event. More calories are burned with 50% from fat.
Anaerobic Zone (Performance Training) --- 80 - 90% of maximum heart rate: Benefits of this zone include an improved VO2 maximum (the highest amount of oxygen one can consume during exercise) and thus an improved cardiorespiratory system, and a higher lactate tolerance ability which means your endurance will improve and you'll be able to fight fatigue better. This is a high intensity zone burning more calories, 15 % from fat.
Red Line (Maximum Effort) --- 90 - 100% of maximum heart rate: Although this zone burns the highest number of calories, it is very intense. Most people can only stay in this zone for short periods. You should only train in this zone if you are in very good shape and have been cleared by a physician to do so.
A relatively fit individual wanting to improve speed and fitness level will incorporate all the zones above at different times in their training. Less fit people and beginners will usually stay in the lower zones.
MEASURING YOUR HEART RATE
Wearing a heart rate monitor is an easy, accurate method of checking your heart rate. If you don't have a monitor here is another easy way:
The easiest place to feel your own heart beat is the carotid artery. Place your index finger on the side of your neck between the middle of your collar bone and your jaw line. (You may also use the radial artery on the under side of your wrist.) You can count the beats for a full 60 seconds or count for 6 seconds and add a zero at the end. If you felt your heart beat 14 times in 6 seconds the number would be 140 for a full 60 seconds. Counting for only six seconds is a convenient method, of course it is more accurate to count for the full 60 seconds. You can use several varieties of this method (30 seconds x 2, 15 seconds x 4, etc.). The longer you count the more accurate your reading. Whatever you choose, be consistent in your method.
When you don't have access to a heart rate monitor or haven't accurately calculated your maximum heart rate you can use perceived exertion as a guide. The following CDC article explains the standard Borg Scale:
The Borg Rating of Perceived Exertion (RPE) is a way of measuring physical activity intensity level. Perceived exertion is how hard you feel like your body is working. It is based on the physical sensations a person experiences during physical activity, including increased heart rate, increased respiration or breathing rate, increased sweating, and muscle fatigue. Although this is a subjective measure, a person's exertion rating may provide a fairly good estimate of the actual heart rate during physical activity* (Borg, 1998).
Practitioners generally agree that perceived exertion ratings between 12 to 14 on the Borg Scale suggests that physical activity is being performed at a moderate level of intensity. During activity, use the Borg Scale to assign numbers to how you feel (see instructions below). Self-monitoring how hard your body is working can help you adjust the intensity of the activity by speeding up or slowing down your movements.
Through experience of monitoring how your body feels, it will become easier to know when to adjust your intensity. For example, a walker who wants to engage in moderate-intensity activity would aim for a Borg Scale level of "somewhat hard" (12-14). If he describes his muscle fatigue and breathing as "very light" (9 on the Borg Scale) he would want to increase his intensity. On the other hand, if he felt his exertion was "extremely hard" (19 on the Borg Scale) he would need to slow down his movements to achieve the moderate-intensity range.
*A high correlation exists between a person's perceived exertion rating times 10 and the actual heart rate during physical activity; so a person's exertion rating may provide a fairly good estimate of the actual heart rate during activity (Borg, 1998). For example, if a person's rating of perceived exertion (RPE) is 12, then 12 x 10 = 120; so the heart rate should be approximately 120 beats per minute. Note that this calculation is only an approximation of heart rate, and the actual heart rate can vary quite a bit depending on age and physical condition. The Borg Rating of Perceived Exertion is also the preferred method to assess intensity among those individuals who take medications that affect heart rate or pulse.
Borg RPE scale
© Gunnar Borg, 1970, 1985, 1994, 1998
Instructions for Borg Rating of Perceived Exertion (RPE) Scale
While doing physical activity, we want you to rate your perception of exertion. This feeling should reflect how heavy and strenuous the exercise feels to you, combining all sensations and feelings of physical stress, effort, and fatigue. Do not concern yourself with any one factor such as leg pain or shortness of breath, but try to focus on your total feeling of exertion.
Look at the rating scale below while you are engaging in an activity; it ranges from 6 to 20, where 6 means "no exertion at all" and 20 means "maximal exertion." Choose the number from below that best describes your level of exertion. This will give you a good idea of the intensity level of your activity, and you can use this information to speed up or slow down your movements to reach your desired range.
Try to appraise your feeling of exertion as honestly as possible, without thinking about what the actual physical load is. Your own feeling of effort and exertion is important, not how it compares to other people. Look at the scales and the expressions and then give a number.
6 No exertion at all
Extremely light (7.5)
9 Very light
13 Somewhat hard
15 Hard (heavy)
17 Very hard
19 Extremely hard
20 Maximal exertion
9 corresponds to "very light" exercise. For a healthy person, it is like walking slowly at his or her own pace for some minutes
13 on the scale is "somewhat hard" exercise, but it still feels OK to continue.
17 "very hard" is very strenuous. A healthy person can still go on, but he or she really has to push him- or herself. It feels very heavy, and the person is very tired.
19 on the scale is an extremely strenuous exercise level. For most people this is the most strenuous exercise they have ever experienced.
Most people in the fitness industry now use a much simpler 10 point version and I love this explanation by Paige Waehner at About.com.