Getting To The Heart Of Things

Posted: January 01, 1989

Some people's hearts are shrunk in them, like dried nuts.

You can hear 'em rattle as they walk.

- Douglas Jerrold 19th-century English humorist

The heart, that perpetually pulsating little music box, has symbolized many things throughout the ages. Recently, because heart disease has become so prevalent in this country, a hearty heart also has come to represent a healthy body.

Today, the heart also is used as a measurement by those who want to pinpoint the exact degree of their fitness. Specifically, a person's heart rate now is used as an indication of overall conditioning. People who work out on a regular basis aim for a low heart rate because it is usually an indication of true fitness. Trained endurance athletes can attain a resting heart rate (a heart rate measured when a person is not in the midst of exercise) of 35 beats per minute. On the other end of the scale, people who haven't exercised since they were members of a Little League team can register a heart rate of a whopping 100 beats per minute.

But why does a low heart rate indicate that a person is fit? Because a heart with a lower rate uses less energy to pump blood throughout the body than a heart with a faster rate, even if the hearts pump the same amount of blood per minute. In other words, the lower your heart rate, the stronger and more efficiently your heart works. Efficiency, however, is the key word

because it represents the relationship between the amount of blood the heart pumps and the amount of energy needed to pump that blood.

EXPLAINING THE DIFFERENCES

How important is a low heart rate? Take a look at two people, Active Art and Couch Potato Pete. Although they may look about the same size, Art exercises four times a week, while Pete is a fairly sedentary guy. Their hearts circulate the same amount of blood (known as cardiac output) per minute. But when the cardiac output is measured by the heart rate times the amount of blood the hearts pump each minute, it is obvious that Pete's heart is less efficient: It has to beat 80 times per minute to pump the same amount of blood that Pete's heart can pump in 50 beats. Thus, Pete's heart works harder to reach the same cardiac output as Art's.

If Active Art and Couch Potato Pete were to take a brisk walk around the block together, Art's heart would work more efficiently to pump more blood with each beat, since his regular workouts enable him to have a low resting heart rate. Pete's heart, on the other hand, is not accustomed to aerobic movement, so it has to beat at a high rate in order to perform the activity.

Although a low heart rate is a plus for everybody, it is especially desirable for people with heart disease, because it reduces the chances that the heart's demand for oxygen will exceed the supply.

If you want to find out your resting heart rate, the best time of day to monitor your pulse rate is in the morning before you get going. That way, the stress of your day and the consumption of any caffeine will not interfere with your reading. Before you jump out of bed, look at a clock with a second hand, place your fingers over your wrist to feel your pulse, and note how many beats you feel in a minute.

THERE ARE WAYS TO IMPROVE

If your resting heart rate is higher than you'd like, you can lower it through aerobic exercise, such as jogging, swimming, biking or walking. When you begin to exercise on a regular basis, your heart rate should begin to decline after several weeks. This reduced heart rate allows your heart to rest longer between beats, and, as a result, more blood enters the ventricles (the chambers of the heart that pump blood throughout your system). Eventually, this increased amount of blood stretches the heart muscle and leads to a stronger contraction and a greater ejection of blood. After a prolonged period of regular workouts, your heart becomes larger and stronger and your heart rate will decline even further.

If you want to start exercising in order to lower your heart rate, make sure you approach these activities at a moderate intensity. If you delve into workouts with a vengeance, your heart rate, oddly enough, will actually increase because you have not allowed your heart enough time to rest and recuperate. As always, get approval from your doctor before starting an exercise program.

Remember, you don't have to be a seasoned triathlete to attain a low heart rate. Even if you don't consider yourself the athletic type, you can exercise your way to a lower heart rate just by starting a regular walking program and sticking to it.

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