FINDING YOUR MAXIMUM HEART RATE
Another example of individuality is each person’s maximum heart rate. Even within a group of athletes of the same age, gender, and ability, the maximum heart rate can vary considerably. There are two ways to find your maximum heart rate. One is by trial, and the other by formula.
The best approach is by trial. Your maximum heart rate for specific activities can be determined following about three to four minutes of maximum (all-out) training, with running being the most effective way to bring the HR to the highest level.
The best formula for determining your maximum heart rate—for healthy adult male and female athletes not on medication—is as follows: 208 minus 0.7 multiplied by age (subtract the result of 0.7 times your age from 208). It’s different than the traditional formula of 220 minus age, which is not as accurate. But even using this or other formulas, athletes usually won’t find the same maximum heart rate as performing a trial. In most cases, actual maximum heart rates are higher.
It should be noted again that your maximum heart rate is not factored into the 180 Formula in obtaining the maximum aerobic heart rate; 180 minus your age is not your maximum heart rate but just a means to obtain your max aerobic rate.
Maximum heart rates vary between different types of activities. Running would produce the highest maximum heart rate compared to cycling or swimming in the same person, due to the increased amount of muscle mass associated with more gravitational stress that accompanies running compared to other activities.
Maximum heart rate may also vary slightly due to a person’s training and stress levels (well rested or tired), nutritional status (such as hydration), weather (high or low humidity), and other factors. This produces a wide variety of maximum heart rates. In a group of forty-year-old athletes, for example, a normal range of maximum heart rates can be 160 to 200 beats per minute. In addition, maximum heart rate diminishes with age in athletes, by about five to ten beats per decade; this, too, can vary considerably with one’s fitness and health.
Despite the inexact science, maximum heart rate has been shown to change with training. In particular, maximum heart rate can decrease with successful aerobic training. This is due to increased efficiency of the heart, improved changes in blood volume, and other factors. It’s also been shown that maximum heart rate can increase during periods of no training, such as during a period of injury when training is reduced.
Regarding anaerobic workouts for activity other than weight lifting, your heart rate should not exceed 90 percent of your maximum heart rate. If you’re doing intervals on a track, use the heart rate as your primary guide, along with total workout time. Betsy, another endurance athlete patient, was a track runner in high school and always enjoyed training on the 400-meter oval. Her choice was to perform one-mile repeats for anaerobic sessions following her four-month base period. With a PR of 41:10 in the 10K, her goal was to eventually break forty minutes. I suggested that she run her mile repeats around a 6:30 pace with an easy quarter- to half-mile recovery at the low end of her aerobic range of 140 to 150. This pace also corresponded with a heart rate in the low 180s at the end of her mile intervals. (Betsy’s maximum heart rate of 197 was determined in a one-mile race six months earlier.)
The main question is this: How is maximum heart rate useful for athletes? While many athletes focus on their maximum heart rate believing that higher is better (which is not necessarily true), there are at least two uses of maximum heart rate. First, I recommend using a percent of maximum heart rate to obtain a general guideline for anaerobic training. This may be the best training intensity that produces maximum training benefits, with training above this heart rate producing little or no additional benefits while adding potentially harmful stress. This figure is 90 percent of maximum heart rate, and can be employed during interval training, hill repeats, and other anaerobic workouts (except weight training, of course).
A second use of maximum heart rate is to compare your actual rate as determined in training to the formula above that predicts maximum heart rate (which generally underestimates the actual maximum heart rate). Athletes who don’t come close to their estimated maximum heart rate could have a problem with their autonomic nervous system, the brain’s control of the heart, blood vessels, or another area. In extreme circumstances, significant differences in the actual versus formula maximum heart rate can even indicate a heart problem and an increased risk of sudden death—these cases are sometimes associated with very low maximum heart rates.
The same type of workout can be performed in other events too. Cyclists, for example, can ride three-, four-, or five-mile distances at their anaerobic effort and slightly faster than the speed of a race. Regardless of the sport, allow your heart rate to come down well into the aerobic zone during the interval recovery. The most significant concern with anaerobic workouts is this: while they must cause a certain amount of stress to be beneficial, they should avoid creating excessive stress. Unfortunately, athletes are often impatient and want to improve too quickly. This only leads to the excess stress associated with overtraining.
After reading an article I wrote on the importance of the aerobic system, Dan, a runner, contacted me. He had just completed a successful winter aerobic base period and was ready for spring track work. Like Betsy, his favorite race distance was 10K, and this year his goal was to break forty minutes. He decided to work out with a friend, and he began his track sessions with quarter-mile repeats at seventy-five seconds each, with a quarter-mile jog in between. When race time came, his times were only a few seconds faster than the previous year. What’s worse, his race times got slower as the season wore on, and he never came close to breaking forty minutes.
Why was Dan doing his intervals so fast? He had not yet broken forty minutes for 10K, so his interval pace of seventy-five-second quarters was far beyond his racing ability—the speed of a runner going at a five minute per mile pace! He would produce much less stress and potentially obtain more benefits if his quarter-mile repeats were ninety seconds instead. This was my recommendation when seeing Dan in my office for the first time.
In addition, running a quarter-mile in seventy-five seconds brought Dan’s heart rate well into the 180s, which was almost his previously determined maximum heart rate. Running the same quarter mile at ninety seconds would bring his heart rate to about 170, closer to 90 percent of his maximum heart rate, and a much more effective level of intensity for anaerobic training: it’s lower in stress, offers significant anaerobic stimulation, and still allowed Dan a slightly faster pace than his racing goal.
I’ve not seen the need for long anaerobic training sessions in endurance athletes. It’s relatively easy to stimulate the anaerobic system to obtain benefits and, unlike aerobic training, shorter bouts of anaerobic workouts are very effective. So, the second principle of anaerobic training is to keep it short. This relates to both the total time of each workout and the number of weeks these workouts are maintained. Both longer anaerobic intervals in a training session and anaerobic training that continues for too many weeks (or months) are common causes of overtraining and injury, and together they can be quite problematic for an athlete’s health.
Your brain, muscles, and metabolism have a limit on what they can gain from a given individual anaerobic workout. And I do mean limit: forty-five minutes for high-stress activity such as running, sixty to ninety minutes for other activities like cycling, skating, and swimming. This is, however, more than sufficient time to get substantial benefits. And remember, these times include your warm-up and cool-down. So after this workout, don’t expect to come home ready to collapse; it’s not necessary.
How long should you continue doing the anaerobic part of your schedule? That depends on a number of factors. The biggest is stress—specifically, how much stress do you have in other areas of your life? Since stress and anaerobic workouts are basically the same because of the hormone cortisol, the more stress in your life, the less anaerobic training you can perform without overtraining.
Another important factor is time. How much time do you have in the course of the day and week, especially considering the increased need for recovery from anaerobic workout (plus all your other aerobic training)? Remember the training equation: Training = Work + Rest.
It takes longer to recover from anaerobic sessions, and if your days and evenings are generally busy with other commitments, you may not have the luxury of doing much anaerobic work.
The best way to answer the question of how long you should continue anaerobic work is by performing the MAF Test. If you see a slowing of your pace at any time during your anaerobic training phase, it’s time to stop all anaerobic work and return to aerobic base training. A worsening of your MAF Test would indicate you’ve done too much anaerobic work. As many athletes find, only a few short weeks of anaerobic training is all that’s required. (Of course, any abnormal indication that the anaerobic sessions are not healthy should also bring the same conclusion—these include disturbances in your sleep, pain, extreme fatigue, and others.)
For most endurance athletes, the maximum time for anaerobic work is about six to eight weeks. But this is the maximum, and more of an exception. For the average endurance athlete who works a forty-hour workweek, especially if he or she has a family, five weeks may be quite sufficient and effective. Want to play it safe? Most athletes can obtain maximum anaerobic benefits after three to four weeks. But for many, no anaerobic training is best. Finding the right scenario for your particular needs is very important, and requires an honest self-evaluation, and not just following other athletes or the latest article in popular sports magazines.
By now, you’re asking yourself the customary question: “How will I get fast if I don’t train fast?” Let me emphasize as I did earlier, and assure you that most endurance events rely on the aerobic system—not the anaerobic—for 95 to 99 percent of the body’s energy needs. You will increase your speed by getting more efficient through aerobic training.
