Determining Your Exercise Heart Rate: The New 180-Formula
Many people who want to fine-tune their exercise and uncover secrets about their bodies' limits, spend quite a bit of time and money reading the magazines about aerobic exercise. Some even spend more on laboratory tests. But the most important information is all free, and takes just minutes.
Some information provides the person with a knowledge about his or her blood lactate and maximum oxygen uptake, respiratory quotient, and heart rate. The last two factors are particularly valuable.
The Respiratory Quotient (RQ) indicates how the body is utilizing oxygen and carbon dioxide. Through this assessment, it can be ascertained whether you are primarily burning fat or sugar while exercising. This procedure is performed by measuring the amount of oxygen the body consumes and comparing it to the quantity of carbon dioxide exhaled. The mathematical ratio of carbon dioxide to oxygen is called RQ (Respiratory Quotient), the R Value, or sometimes the Respiratory Exchange Ratio (RER). The RQ ranges from 0.7 to 1.0. As your R Value gets closer to 0.7, it denotes that more fat is being used to fuel the body. And when the value tilts closer to 1.0, this suggests that sugar, in increasing amounts, is the dominant energy source.
The second factor—heart rate—can be used alone to reliably portray all the previously mentioned research that sports lab performs. This is possible since the heart rate accurately parallels these other factors. In effect, there is an inexpensive and practical method for evaluating your physical condition as well as the effectiveness of your workouts right at your fingertips.
This was not always the case. Up until the early 1980's, there were only two heart rate evaluation procedures available: the talk test, which originated with the 1970's running craze, an a quasi-scientific formula based on an athlete's chronological age. When applying the talk test, it is assumed you are exercising within the aerobic range if you can comfortably talk to your training partner during a workout. This test however, is about as reliable as the flip of a coin, since the chances are 50-50 you will be either right or wrong.
Given these odds, the quasi-scientific method seems infinitely more reliable for structuring a training program based on the athlete's heart rate. This system, which is still widely used today, instructs riders to subtract their age from 220 and multiply the difference by a figure ranging from 65 to 85 percent. Supposedly, the resulting number provides the athlete with the maximum heart beats per minute (bpm) for keeping workouts aerobic or, some say, just at the anaerobic threshold (AT).
Technically, exercising at AT means you have reached the highest level of oxygen uptake, or the point at which, regardless of the workload, you can't consume any more oxygen. Yet, the term threshold, anaerobic threshold refers to the onset of anaerobic exercise. This approach to exercise, therefore, emphasizes anaerobic efforts however mild they may be, as opposed to aerobic activities.
The assumed rationale for the old formula contains two fallacies. First, it assumes that 220 minus age will render your maximum pulse rate. In reality, most people who push themselves to the maximum in order to obtain their maximum heart rate will find it is not 220 minus their age. It is often above or below that number. Second, the multiplier (65%-85%) is an arbitrary figure that doesn't consider your overall health and fitness. Does one use 65%, or 75%? How about 80%, or 70%? Without having a more precise indicator, you are left to guess a percentage.
An accurate method to determine your heart rate is, therefore, essential for realizing your overall well-being. In a medical setting, ascertaining the exact relationship between heart rate and aerobic state is achieved by clinically establishing an athlete's true, or physiological, age. Different doctors do this in different ways. What they commonly evaluate, however, are the lungs' vital capacity, blood sugar, and the condition of the heart (by using an electrocardiogram), as well as an individual's personal and family history.
What becomes readily apparent from such medical analysis is that a 40-year old may have the body efficiency (the ability to perform an athletic task) of an individual either 10 years older or 20 years younger. As a consequence of physiological condition, the true age of these 40-year old would be closer to 50 and 20, respectively.
Doctors can help people establish their correct exercise heart rate. Yet it is quite possible to make this determination on your own with reasonable accuracy. All you have to do is to follow this easy 2-step formula:
Step l: Subtract your chronological age from 180.
Step 2: Place yourself in one of the four following categories below and adjust the number derived in Step 1.
a. If you have never trained before, are recovering from a major injury, operation, and/or illness, or are taking medication, subtract 10 from the number obtained in Step 1.
b. If you are currently exercising, but have been falling short of your goals (e.g. improved fitness, better competitive results, more energy, weight loss, etc.), or your workout routine is inconsistent, or you have suffered an injury (even a minor one), or you have had more than 2 colds or cases of the flu during the past year, subtract 5 from the number obtained in Step 1.
c. If for the past year you have worked out consistently (4 or more times per week), have progressed to your satisfaction (feel fitter, enjoyed improved competitive results, have more energy, lost weight, etc.) and have not suffered any injury or experienced no more than 2 colds or cases of the flu, do not alter the number obtained in Step 1.
d. If you are a competitive athlete, and your performance has improved over the past two years, you have not suffered any injuries or experienced more than 2 colds or cases of the flu during the past year, add 5 to the number obtained in Step 1.
More than likely, you will easily be able to find a suitable category and obtain a specific numerical value. This figure, regardless of the category, is the maximum heart rate that will keep you aerobic when training.
'In Between' Status
Some individuals, however, may be in a quandary over how to determine their exact maximum heart rate figure. That's because, due to a variety of circumstances, they feel as though they fall in between categories. If you are in this situation, just select the more conservative number.
Here is a typical example of a person who qualifies for 'in between' status. He is 35 years old and has been working out for 3 years despite experiencing a nagging injury (e.g. a minor knee problem or lower back pain). If your situation is similar, no matter how old you are, compute your maximum heart rate in this manner:
Step 1: 180 minus age. 180 - 35 = 145
Step 2: Choose category b and subtract 5. 145 - 5 = 140
In this case, your maximum heart rate, therefore, would be 140 bpm. Generally, the figure derived this way will enable training without harming the body and still provide fat-burning, aerobic benefits. Should your heart rate exceed 140 bpm, however, you would not only start burning much more sugar and less fat, but also risk the possibility of aggravating the injury.
All people, upon arriving at a number that indicates their peak heart rate, should establish a bpm range. The most serviceable span is 10 bpm below your top-end, since it's often difficult to keep your heart rate at its designated maximum. If your maximum aerobic heart rate is 160 bpm, for example, you will still derive conditioning and health gains at your low-end of 150 bpm.
Since the 180-formula takes into account an person's health as well as fitness, it will be more precise than its 220-counterpart. The 4 categories, however, are similar in rationale to the 65 to 85 percent multipliers prescribed in the 220-procedure. Yet, even in this area, the 180-method has demonstrated greater accuracy.
Since around 1982 the 180-formula has been used to clinically monitor the heart rates of individuals whose abilities ranged from superstar to novice. Moreover, during this period, the 4-category plan has proven to be much more reliable than the percentage multiplier approach as a means of establishing an individual's maximum heart rate. And even more significant is the fact that, when compared to laboratory tests, the 180-equation correlated amazingly well.
While the 180-equation can confirm your correct target zone, you must still have a reliable means of determining your heart rate, whether using a heart monitor or manually taking your pulse.