The Big Book of Endurance Training and Racing

by Dr. Phil Maffetone
The 180-Formula and Heart-Rate Monitoring

An important training companion to assist you in developing optimal endurance and better fat burning is a heart-rate monitor. This simple device is a valuable tool that not only guides your training but is part of an important assessment process, and can even be used in some competitive situations. 

A heart monitor is really a simple biofeedback device. Dorland’s Medical Dictionary defines biofeedback as “the process of providing visual or auditory evidence to a person of the status of body function so that you may exert control over that function.” Unfortunately, most people use their heart-rate monitors only to see how high their heart rate gets during a workout, or evaluate the morning, resting heart rate.

In the 1970s, I first measured heart rates as a student involved in a biofeedback research project. I observed and jotted down responses in human subjects to various physiological inputs, such as sounds, visual effects, and other physical stimulation, including exercise. The subjects’ reactions were evaluated by measuring temperature, perspiration, and heart rate. Through this research, it became evident that using the heart rate to objectively measure body function was simple, accurate, and useful, especially for athletes. I began using the heart rate to evaluate all exercising patients, and by the early 1980s developed a formula that anyone could use with their heart monitor to help build an aerobic base. This “180 Formula” enables athletes to find the ideal maximum aerobic heart rate in which to base all aerobic training. 

The heart rate is directly related to, and a reflection of, the body’s oxygen need. The heartbeat, the outcome of the heart’s muscular contraction to help pump oxygen-rich blood through the body, is also associated with systolic blood pressure, while diastolic blood pressure reflects relaxation of the heart as measured between beats. The relationship between two heartbeats is associated with heart rate variability, reflecting our parasympathetic aspect of brain and nervous system function—this being an important factor for professionals to assess heart health and for athletes to evaluate recovery from training and racing.

The heart itself has a built-in mechanism of nerves that controls its own rhythm (to maintain a heart rate of around 70 to 80 beats per minute), but the brain, through the action of the autonomic nervous system and various hormones, controls the wide range of heart rates based on the body’s needs. This rate can be as low as 30 to 40 in those with great aerobic function to as high as 220 or higher in young athletes during all-out efforts. 

Abnormal heart rates also fall within this range, sometimes making heart rates inaccurate. For example, in the later stages of the overtraining syndrome, the resting heart rate is abnormally low; and those who are too stressed can have abnormally high resting and training heart rates.

In my continued attempt to individualize training heart rates, in the late 70s and early 80s I had several bulky heart monitors in my office, used for accurate heart rate evaluation. Whether the athlete was on a treadmill or stationary bike in the clinic, on the track, or at other locations, I would record a number of pre- and post-workout features. These would include the athlete’s gait—their moving posture during the workout—along with standing posture and muscle balance, and I would correlate this mechanical efficiency with heart rate at various points before, during, and after workouts. It was obvious that training at various intensities affected both posture and gait: the more anaerobic, the more distortion of the body’s mechanics. These changes are due, in part, to previously existing muscle imbalance and muscle problems that develop during the workout. This is sometimes very subtle and other times more obvious. All this information was correlated, and ultimately, an ideal training heart rate was found that promoted optimal aerobic function without triggering significant anaerobic activity, excess stress, muscle imbalance, or other problems.

It soon became evident that the athletes needed more consistent training quality, rather than relying on the feel of the workout on the day they used the heart monitor. It became necessary for each athlete to have his or her own heart monitor and train with it every day. The advent of modern heart monitors, which sensed the heart rate directly from the chest wall and transmitted the information to a wristwatch, was a great benefit in this regard, with Polar’s entry into the marketplace in 1982. One of the most significant observations I made during this period was that athletes who wore heart-rate monitors during each workout felt better and improved in performance at a faster rate than others who trained without a monitor.

It was now possible to find an ideal training heart rate for athletes building their aerobic system; however, it was a relatively lengthy process of one-on-one assessment. My goal now was to find a way that any athlete could determine an optimal training heart rate, using some simple formula.

As I began lecturing and writing more about endurance training, it was difficult to explain the details of all this information on assessment without some simple and specific guidelines. The idea of a formula that would be accurate for an individual and result in a very similar or identical heart rate as my manual assessments seemed ideal. While the 220 Formula was commonly used, the number I found to be ideal in my assessment was often very different from the 220 Formula; it was usually significantly lower. In addition, it was becoming evident that athletes who used the 220 Formula for a daily training heart rate showed poor gait, increased muscle imbalance, and other problems following a workout at that heart rate, and that these athletes were more often over trained.

There are two ways to define age. Chronological age is measured by calendar years, but this may not be a good reflection of fitness and health. We all know athletes who appear much younger—or older—than their chronological age. Some maintain better levels of physical, chemical, and mental function throughout life, reflecting a truer physiological age, while others who are the same chronological age do not. We can evaluate these differences by measuring heart and muscle function, blood sugar, and hormone levels, and by performing other clinical tests. An appropriate questionnaire that asks about fitness and health history is also very useful to assess physiological age, and would better represent “age” in a new and more accurate formula.

Over time, I began piecing together a mathematical formula, taking the optimal heart rates in athletes who had previously been assessed as a guide. Instead of 220 minus the chronological age multiplied by some percentage, I used 180 minus a person’s chronological age, which is then adjusted to reflect their physiological age as indicated by fitness and health factors.

By comparing the new 180 Formula with my relatively lengthy process of one-on-one evaluations, it became clear that this new formula matched very well—in other words, my tedious assessment of an athlete and the 180 Formula resulted in a number that was the same or very close in most cases.

Early in this process, I made number of relatively minor changes to the formula. By the early 1980s, I settled on the final, most effective formula and this is the one in use today: 180 minus a person’s chronological age, which is then adjusted to reflect their physiological age as indicated by fitness and health factors. The use of the number 180 was and is not significant other than as a means to finding the end number. Plus, 180 minus age itself is not a meaningful number; for example, it is not associated with VO2max, lactate threshold, or other traditional measurements. The end number is an athlete’s maximum aerobic heart rate. This is the training heart rate that reflects optimal aerobic training, and a number which, when exceeded, indicates a rapid transition to more anaerobic training. Through the use of this 180 Formula, all athletes can obtain their ideal individual aerobic training rates.

Calculate Your Own Maximum Aerobic Training Heart Rate

To find your maximum aerobic training heart rate, there are two important steps. First, subtract your age from 180. Next, find the best category for your present state of fitness and health, and make the appropriate adjustments:

1. Subtract your age from 180.

2. Modify this number by selecting among the following categories the one that best matches your fitness and health profile:

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

b. If you are injured, have regressed in training or competition, get more than two colds or bouts of flu per year, have allergies or asthma, or if you have been inconsistent or are just getting back into training, subtract an additional 5.

c. If you have been training consistently (at least four times weekly) for up to two years without any of the problems just mentioned, keep the number (180–age) the same.

d. If you have been training for more than two years without any of the problems listed above, and have made progress in competition without injury, add 5.

For example, if you are thirty years old and fit into category (b), you get the following:

180–30=150. Then 150–5=145 beats per minute (bpm). 

In this example, 145 will be the highest heart rate for all training. This is highly aerobic, allowing you to most efficiently build an aerobic base. Training above this heart rate rapidly incorporates anaerobic function, exemplified by a shift to burning more sugar and less fat for fuel.

If it is difficult to decide which of two groups best fits you, choose the group or outcome that results in the lower heart rate. In athletes who are taking medication that may affect their heart rate, those who wear a pacemaker, or those who have special circumstances not discussed here, further individualization with the help of a healthcare practitioner or other specialist familiar with your circumstance and knowledgeable in endurance sports may be necessary.

Two situations may be exceptions to the above calculations:

• The 180 Formula may need to be further individualized for people over the age of sixty-five. For some of these athletes, up to 10 beats may have to be added for those in category (d) in the 180 Formula, and depending on individual levels of fitness and health. This does not mean 10 should automatically be added, but that an honest self-assessment is important.

• For athletes sixteen years of age and under, the formula is not applicable; rather, a heart rate of 165 may be best.

Once a maximum aerobic heart rate is found, a training range from this heart rate to 10 beats below could be used as a training range. For example, if an athlete’s maximum aerobic heart rate is determined to be 155, that person’s aerobic training zone would be 145 to 155 bpm. However, the more training at 155, the quicker an optimal aerobic base will be developed.

Initially, training at this relatively low rate may be stressful for many athletes. “I just can’t train that slowly!” is a common comment. But after a short time, you will feel better and your pace will quicken at that same heart rate. You will not be stuck training at that relatively slow pace for too long. Still, for many athletes it is difficult to change bad habits.

Case history

One of my patients by the name of Don was a good runner who usually placed in the top of his thirty to thirty-nine age-group. When he came to my clinic with chronic injuries, fatigue, and recurrent colds, one of the first things we did was test him on the track with a heart monitor. At his maximum aerobic heart rate, Don was only able to run at an 8:40 pace—almost two minutes slower than his usual training pace! I recommended that Don train at this slower pace with a monitor for a three-month base period. But two weeks later he called me and said it was impossible to run that slow. I again explained the whole process and how he would get faster. A week later he faxed a letter saying he could not train by my recommendations. But several months later, with worsening fitness and health, and almost unable to race, Don came back to the clinic. Now he was ready to train aerobically. It took several months of dedicated base building, beginning with a slower pace, for Don to increase his aerobic pace until finally he was running his “normal” 6:45 training pace—but this time at a heart rate that was twenty-five beats lower than our previous evaluation.

***

The accuracy, usefulness, and importance of the formula have been time-tested throughout the years. But by the early 1990s, many of the athletes I’d worked with for a decade or more taught me another important lesson about the 180 Formula. Seeing the changes they made, including some longer than normal plateaus, helped me come to an important conclusion: Those using the 180 Formula successfully for more than five years needed to adjust their maximum aerobic heart rates down by about two to three beats. They could not keep using the same maximum aerobic heart rate they’d determined years earlier, despite healthier aging. While we age over time chronologically, building fitness and health during the same period results in a slower physiological aging. So in five years of proper (successful) training and improving health, your training heart rate does not need to be lowered by five beats; instead, because you’re physiologically not as “old,” decrease only by two to three beats. When in doubt, always choose a lower maximum aerobic heart rate. This assumes the factors in the 180 Formula that pertain to medication, illness, and competitive improvements are the same. Otherwise, further reductions in the training heart rate may be necessary.

With expressed written consent of Dr. Philip Maffetone to runningcastles.blogspot.com