Understanding Your Heart Rates and Exercise

February is Heart Month, and I had every intention of creating an article regarding your heart rate and exercising. Then this gem of an article popped up on Facebook yesterday and it said it all for me, so why re-create perfection when it's already done for me?

The following article is courtesy of Active.com

By Mike Siemens, M.S.
Director of Exercise Physiology


What is the optimum heart rate to exercise at for fitness improvement and fat burning? What does my resting heart rate tell me? Why is my heart rate always so high? If you find yourself asking these questions, you are not alone. Very few people know the answers to these questions and even fewer understand the physiology behind the answers. Since understanding your heart rate is critical to exercising safely, effectively and enjoyably, the next four articles will address these questions and discuss heart rates and exercise.
In this first article, I will define maximum and target heart rates and explain how they relate to exercise. I will also discuss the most accurate methods for identifying your target heart rate.

What Is Your Maximum Heart Rate?

Maximum heart rate is the highest beats per minute your heart can achieve. It is not sustainable since it is an all out effort. It is essential to know your personal maximum heart rate in order to calculate effective target heart rates to use during exercise.

It is always amusing to me when a client comes in for an appointment and says, "Whew, I just finished that spinning class and I worked at my maximum heart rate for 30 minutes straight!" This is impossible to do because even the most highly trained, professional athletes in the world can only maintain their maximum heart rates for three to four minutes. Any longer and they would collapse with exhaustion.

To understand what maximum heart rate is read the following scenario:
I put you on a treadmill and I increase the speed or the incline every minute until you fall off the back of the treadmill exhausted. We do not stop the test until you are physically exhausted. I record your heart rate every minute as you push yourself harder than you ever felt possible. When every cell in your body wants to stop you push through for a minute or two longer -- faster, steeper all the while. Your heart rate plateaus -- even though I continue to increase the workload for another minute or two. Finally, your muscles succumb to the fatigue and you collapse with exhaustion. (Note: Do not under any circumstances try this at home without prior physician clearance and even then it can be dangerous.)

The heart rate at which you plateau is your maximum heart rate. I want to reiterate that this is hard, all out maximal exertion. The good news is that you do not need to train at this level of effort or intensity unless you are training for a specific event that requires this type of exertion.

Here are some interesting facts about maximum heart rate:

• Maximum heart rate is not a trainable attribute. This means as you become more or less fit -- your maximum heart rate does not change.
• The more fit you become the more work you can do at your maximum heart rate. This means you will be biking, swimming or running faster with improved fitness.
• Medications in the Beta blocker family (Lopressor, Tenormin, Lopid, Metoprolol, Atenolol Propranolol etc.) will lower your resting heart rate and your maximum heart rate.
• Maximum heart rate is not correlated to fitness level. The amount of work you can do at your maximum heart rate is the thing that is related to your fitness level.

What Is Your Target Heart Rate?

Mathematically it is the range between 70 and 85 percent of your maximum heart rate.

• Depending on your medical history, this might be altered so be sure to discuss it with your doctor if you have any health concerns at all.
• Different types of workouts might call for slightly different intensities

What are the Benefits of Knowing Your Target Heart Rate?

• Guaranteed optimal calorie and fat burning during your workouts.
• Optimal fitness and performance improvement.
• Maximal enjoyment of exercise time. 

How Do I Calculate my Maximum Heart Rate and Ideal Target Heart Rate?
 

Methods with High Potential for Error:

The Charts

We have all seen them hanging there on the gym wall. These charts use columns where you find your age and the correlating target heart rate zone. These charts can produce errors of plus or minus 20 beats per minute! The reason for this huge potential error is that they all use the generic formula of 220 -- AGE = maximum heart rate. This can be off by as much as +/- 30 beats per minute! In real life this means if you are 50 years old -- the charts will predict a maximum heart rate for you of 170 beats per minute. Meanwhile, your true maximum heart rate could be as low as 140 or as high as 200 beats per minute. That is the normal range of human maximum heart rates. From the charts you have no way of knowing if your maximum heart rate is lower or higher than 220 -- AGE. Remember that your maximum heart rate tells us nothing about your fitness level. 

Exercise Machines and Heart Monitors
Unfortunately, these pieces of equipment use the same 220 -- Age estimation of maximum heart rate as the charts do. So any time you provide the equipment with your birth date or age, the on-board computer software is calculating 220 -- Age and all of the potential error that comes along with it.


Methods with Higher Accuracy: 

An EKG (Electro Kardio Gram) Exercise Stress Test With a Physician

Most of the time these tests are done to screen people for safe participation in exercise. As a result, physicians are usually focused on looking for heart disorders such as arrhythmias and or changes in your EKG that suggest problems.You need to advocate for yourself here and let your doctor know that you would like to know what your maximum heart rate is and what your optimal heart rate range is for exercise.

During this test, you are hooked up to 12 electrode leads and put through a graded exercise test. "Graded" means that the work you are doing is increased every minute or so until either you get too tired to continue or your doctor stops the test. Since this test actually measures your individual heart rate response to exercise, your real maximum heart rate can be determined.

Keep in mind that most of the time these tests are stopped before actual maximum heart rate is reached. This is absolutely fine and normal (remember the description of what maximum heart rate feels like from above). However, since the test will not take you to your maximum heart rate, you and your doctor need to extrapolate what your actual maximum heart rate is. Some cardiologists will calculate a stopping point of the test of 85 percent of your age-predicted maximum heart rate. By now you should know that this is not necessarily going to be 85 percent of your maximum heart rate and is most likely not going to be your true maximum heart rate.

Once you and your doctor estimate your actual maximum heart rate, all that is left to calculate is 70 to 85 percent of that maximum to arrive at your target heart rate. 

A Submaximal Exercise Test With an Exercise Physiologist

This test is done by an Exercise Physiologist (Look for a practitioner with a degree in the field and at least one certification from the American College of Sports Medicine). The physical part of the test is almost identical to the EKG exercise stress test discussed above. The primary differences are:

In the submaximal test with an exercise physiologist you will wear a heart monitor strap, not the 12 lead EKG electrodes. Therefore, this is not a diagnostic test. You must have clearance from your doctor permitting exercise program participation to do the submaximal test.

The submax test can be done on any piece of cardiovascular exercise equipment such as a treadmill, stationary bike, elliptical, stairclimber, rowing ergometer, etc. In this test you will wear a portable telemetric heart rate monitor during an eight to 15 minute graded exercise test. Every two minutes or so your exercise physiologist will increase the workload and record your heart rate. You will also be asked to rate the level of exertion you are feeling in your legs and breathing.

The exercise physiologist should be trained at determining 70 to 85 percent of your maximum heart rate based upon your exertion level, breathing pattern and speech pattern. These tests should always be stopped at 85 percent of maximum heart rate unless a physician is on the premises.

The take home message here is do not rely upon the charts or any other mathematical calculation to determine your maximum heart rate or your target heart rate zone. There is simply too much biological variation in heart rates to use anything other than a test which measures your individual response to exercise.

I cannot stress enough how important it is to have a stress test done, as well as the aforementioned tests prior to starting ANY exercise program. It is also extremely important to have on a heart rate monitor anytime you exercise. This way you can see how hard you are and are not working. The monitors on the treadmills and elliptical machines are just a guideline, and are NOT what is actually going on because there are way too many factors involved, like the ones mentioned, plus if you are gripping the sensors too tight your HR is going to go up.

You can purchase two types of HR monitors: 

The first one is a HR monitor with a chest strap (which is what I use because i trust it more as it's monitor is right by my heart) that send the data to a watch on your wrist. (I need to mention that the this type of monitor can be annoying to some as it is wrapped around your chest and back the entire time, and has to be cleaned after every workout).

The second is a wrist monitor; it has the same design as #1 but there is no chest strap. It is important that if you do purchase one like this that it is accurate, so you may have to test it out before establishing it's accuracy, and this has to be cleaned after every exercise as well.


Another tip I want to mention is when weight lifting, keep a firm grip on the weights, but don't squeeze too tightly as this causes your blood pressure to go up and also creates fatigue in your forearms. 

Yours in Fitness,

Tara