Is your cardio exercise program designed around heart rate training? If so, great! Heart rate training helps you make faster progress more comfortably and with less risk of injury and burnout. But how did you come up with your target heart rate numbers? Did you just follow a simple formula like “220 minus your age?” If so, you may be undercutting your fitness efforts because the truth is, most formulas can’t give you an accurate measure of your maximum heart rate (Max HR). In fact, simple age-based formulas may lead you entirely astray.
Method or Madness?
There are several methods for determining how hard you should be working during any given workout. Many of them are based on achieving targeted exertion levels (zones) defined by percentages of your Max HR.
Max HR is the highest heart rate value you can achieve in an all-out effort to the point of exhaustion. Obviously, it’s rarely the goal of any workout to take you to a point of all-out exhaustion, but using percentages of your individual Max HR to determine the appropriate intensity for a given workout (or series of workouts) can help create more efficient and effective fitness routines. For example, working out at half your Max HR is great for improving your health and increasing your base level of fitness, while working out at 75 percent of your Max HR is a great way to improve your cardiovascular capacity and endurance.
So knowing your Max HR has its merits. But the best method for determining Max HR remains a hotly debated topic. For quite some time now, the best known Max HR-estimating formula has been “220 minus your age.” While this formula does happen to prove accurate (or close to accurate) for some people, for others it turns out to be woefully off base.
Exercise physiologists have long questioned and researched this method’s reliability, and today there is a general consensus among informed fitness experts that Max HR cannot reliably be deduced using such a simple formula. The main problem is that Max HR is not influenced so much by age as by genetics. In fact, most people of similar age do not have the exact same Max HR.
For instance, exercise physiologists Jack H. Wilmore, PhD, and David L. Costill, PhD, authors of Physiology of Sport and Exercise (Human Kinetics, 2004) have reported that the Max HR of 95 percent of all 40 year old men and women falls somewhere between 156 and 204 beats per minute. But that’s a big margin, particularly when you consider that most heart rate zones (determined by Max HR) are carved out in ranges of 20 beats a minute or less. The lesson here: Estimate your Max HR wrong, and you can easily get your zones all wrong too.
Testing for Accuracy
So if the standard formula can’t be trusted, then how do you determine your Max HR? There are basically three methods: good, better and best.
The “good” method is to use a slightly more complex formula that takes into consideration more personal variables than just your age. One formula (which can provide a more highly dependable but still not perfect estimate) is: 210 minus one-half your age; minus five percent of your body weight (in pounds); plus four (for men) or zero (for women). This formula has been tested on thousands of people, and the results typically fall within five heartbeats of a person’s true Max HR. Of course, even this formula leaves something to be desired, but it beats the simple “220 minus age” hands down.
The better and more accurate method of estimating Max HR involves employing maximal and submaximal tests to evaluate your body’s reactions to real aerobic loads. The very best of these options employs sophisticated VO2-max equipment to pinpoint your body’s biochemical reactions at various stages of exertion. A maximal test (with or without specialized equipment) can give you a very good idea of your real Max HR, but because by definition it requires an all-out effort, it is very physically demanding, requires supervision and is not advised for people who are not already in relatively good to excellent shape. (If you are a candidate for a max test, see Chart A below on how to conduct one.)
Chart A - Maximal Stress Test
If an individual is already in good shape and 35 years old or younger, then he or she should be able to safely undergo a maximal stress test. (If you have a client who is older than 35 or has a heart condition, advise them to seek assistance from a qualified professional.)
It’s easiest to do the test on a treadmill or cycle ergometer, but you can also use a running track or nearby hills. Avoid any vigorous activity the day prior to the test and don’t eat two hours before. Then have your client do the following:
- Warm up adequately for at least 15 to 20 minutes, staying at an intensity that permits comfortable conversation.
- Gradually increase the intensity by upping the resistance to elicit an increase of five beats every 15 seconds. Most people will reach their maximum heart rate within two to four minutes. At your maximum, you should feel exhausted and only able to hang there for a few seconds.
- Be sure to cool down upon concluding the test. If the client gave it absolutely everything, the biggest number on your heart rate monitor during this test should be close to their true maximum. If they felt like they quit a bit early, then add three to five beats to the largest number to determine their maximum heart rate.
Submax tests are less taxing and can still offer a precise assessment of your Max HR - better than any formula. There are many submax tests from which to choose. The Easy-Moderate-Hard Test (see Chart B below) is ideal for people who already work out regularly. It’s easy to perform and doesn’t require any special equipment or supervision.
Chart B - The Easy-Moderate-Hard Test
Warm up for five to 10 minutes. Then complete the following three exercises, in this order:
|EASY: Select any cardiovascular activity you enjoy, such as walking, running, cycling, stepping or rowing. Do it for two minutes or one lap around a track at “very, very easy to easy” effort. (On a 1 to 10 perceived exertion scale you should feel between 1 and 3 perceived exertion.) Note your “easy” heart rate.
|MODERATE: Do the same activity for the next two minutes or an additional lap and increase your effort to a level that feels “somewhat hard to hard” (perceived exertion of 4 to 6). Note this “moderate” heart rate.
|HARD: Do the same activity for two minutes more or one extra lap and increase your effort to an intensity level that feels “harder to very, very hard” (talking will be limited to short and choppy phrases; perceived exertion of 7 to 9). Note your “hard” heart rate.
To estimate your Max HR, add the appropriate numbers below to each of your corresponding exercise heart rates. Total the three values, then divide by three to get your estimated Max HR.
- Easy: Add 60 to exercise heart rate
- Moderate: Add 40 to exercise heart rate
- Hard: Add 20 to exercise heart rate
Making the Most of Your Max
Now that you have a more accurate Max HR, what do you do with it? Begin by working within the following five training zones: Zone 1: Healthy Heart; Zone 2: Temperate; Zone 3: Aerobic; Zone 4: Threshold; Zone 5: Redline. These zones cover a complete continuum of exertion.
You reap different benefits in each zone, so you want to choose your zones (and the amount of time you spend in each one) depending on your current fitness level and your goal for a given workout. The following are a few suggestions to help guide you toward choosing the appropriate intensity zone.
If you are just beginning a fitness program, spend the first two weeks in Zones 1 and 2 (50 to 70 percent of Max HR). After a couple of weeks, add some time in Zone 3 (70 to 80 percent of Max HR). To reduce potential injury, it is important to progress gradually. If you are already active, then use Zones 1 and 2 primarily for warm up and cool down and spend approximately 50 percent of your total cardio training time in Zone 3 (70 to 80 percent of Max HR), which can help improve aerobic capacity.
Once you have established a strong cardio base, devote approximately 15 percent of your total cardio training time to Zone 4 (80 to 90 percent of Max HR). This will help to raise your threshold. This is also where you burn the greatest total amount of fat calories in the shortest duration of time.
If you require speed to reach your performance goals, then devote about 10 percent of your weekly time in Zone 5 (90 to 100 percent of Max HR). Time spent in Zone 5 can improve your lactate tolerance and clearance. Too much time in Zone 5 can result in injury and burnout.
Keep in mind that your level of fitness is reflected not in having a high or low Max HR but rather in the percentage of your own Max HR that you can sustain during a training session. The longer you can sustain a heart rate in the upper percentage of your Max HR, and the more comfortable you are while there, the fitter you are becoming.
It’s a good idea to assess your maximum heart rate a couple of times each year. In addition, if you train in a few different modalities (i.e., swimming, biking and running), it is important to determine your maximum heart rate for each of those activities. Studies have shown that maximum heart rate for running is typically five to six beats higher than cycling, two to three beats higher than rowing and around 14 beats higher than swimming.