A dusty treadmill sits in the corner,
A mountain bike is transformed into a coat hanger,

and the stairclimber is just a living room ornament. Each piece of equipment beckons to the couch potato whose only exercise consists of pushing the buttons of the remote control. But today is a new day, and the couch potato has resolved to get up and complete a vigorous cardio-vascular workout. Dusting off the treadmill and throwing the clothes off to one side, he laces up his running shoes, and turns the aged piece of equipment on. After only two minutes of a fast paced run, he is tired out almost to exhuastion. This is due to years of limited exercise and a poor diet. His heart has to work much harder now because of the buildup of plaque in his arteries, which reduces blood flow.

The heart, a muscular organ, has four chambers. Two atria, the receiving chambers, and two ventricles, the pumping chambers. When the body is put into motion, such as in exercise, the heart has to pump more blood in order to supply a greater amount of oxygen that the cells demand. Deoxygenated blood from the body fills the right atrium and is pushed through a valve to the right ventricle. These contractions are called systoles. The blood is then forced into the lung artery and to the lung where it then passes through capillaries. The carbon dioxide picked up from the body is deposited here, and the blood leaves the lung with oxygen and returns to the left atrium. From the left atrium, the oxygenated blood flows through the left ventricle and to the aorta, the largerst artery in the body. This artery, in turn, branches off into several other arteries and veins, and the blood is carried throughout the body.

Since the couch potato is not used to working out, his heart is beating very fast, he is breathing hard, and he is hot. This is all due to the need for more oxygen to continue the pace. But, with continued and regular exercise, the heart becomes stronger and therefore can supply more blood in each beat. This produces a lower and healthier heart rate.

As the couch potato steps off the treadmill, he sighs with relief from the pain he has had to undergo, but has definitely realized the advantages exercise has towards his heart and circulatory system.

While a human's heart beats about 60 to 80 times a minute,
a hummingbird's heart beats a remarkable 500
to 600 times per minute.

The smaller the animal, the higher their heart rate is likely
to be.


In the course of an average 72 year life span, the
human's heart is likely to beat

more than an estimated 2,649,034,000 times
total.



The tiny blood vessels that distribute blood throughout the
body are known as capillaries. This word
comes from the latin word meaning hair. But, these tiny
vessels are far thinner than even
the finest peice of hair.



The Giraffe's long neck and tall body are very efficeint
in helping it obtain food, but blood

flow to the body becomes very difficult. To aid this
situation, adaptations have caused the
giraffe to have pumping ventricles in its neck as well as the heart.
This helps to prevent the animal from blacking out everytime
it reaches up to have a snack.

Miracle drugs, lifesaving open heart surgery, and new, sophisticated equipment are among the options that people who suffer from heart disease have. Some of the diseases that people may suffer from are congenital heart disease, a defect that is present at birth, such as a hole in the septum, and rhematic fever, which damages the heart valves with scar tissue. Perhaps the most serious heart disease is when one suffers a heart attack. This may be caused by blockage of arteries or veins, and if the coronary arteries are affected, it is considered very serious. A heart that is very badly damaged by a heart attack can no longer pump and heart failure occurs.


Specialized heart doctors called cardiologists use a variety of tests to help determine if there is anything abnormal about the heart. These tests may be conducted on people who have already had a heart attack or are in the high risk category to have one. An Electrocardiogram is a record of the electrical activity of the heart. It uses waves to show the excitation of different parts of the heart, and helps to display abnormalities in cardiac rhythm and myocardial damage. An X-ray may be taken of the heart that produces a shadow like picture and allows the doctor to view the heart's size, shape, its chambers, and the larger blood vessels. Also, a fluroscope can be used to study the motion of the heart.

If a heart attack occurs and is due to plaque buildup or closure in the arteries, two methods of surgery can be done. Bypass surgery is used when the clogged portion of the artery or vein is replaced with a healthy vein usually taken from the leg or arm. Balloon angioplasty is used when a tiny balloon is inserted into the affected area and is pushed open just enough to remove the plaque from the artery. A newer method of removing plaque buildup that is yet to be fully developed invovles directing a beam of laser light to the affected area and ZAPPING the gunk away. This non-invasive surgical technique has great potential and advantages for both the patient and surgeon.

If the heart is so badly damaged that no amount of surgery can repair it, a heart transplant is needed.

This is a more complex process that requires more precautions and increased care after the lengthy surgery. The doctors must make sure that the body does not reject the transplanted organ and cause self destruction. However, new technology is developing every day and the science of cardiology is advancing at a very rapid rate.

Images copyright PhotoDisc, Inc., 1996.
Images copyright T/Maker Company, 1996.
New Book of Knowledge, 1987. Grolier Inc.