This slow beat is also the most efficient, because the heart is then taking a minimum of blood for its own nourishment through its coronary arteries. And when the trained heart speeds up, as it must on demand for a burst of physical activity, it still accelerates more slowly than the "loafer's heart" and never attains as high a rate for the same work load.
The trained heart gets that way by being lodged in a youngster who stays highly active into the years when formal athletic training takes over. If this young man does not start smoking he will have little to worry about through his college years. Heart and arteries will remain almost completely healthy, though a few little fatty plaques may develop. Even the American diet, overrich in both fats and starches, will do him little detectable harm up to this point, because he will burn up the calories. The trouble for his heart begins after he takes a sedentary job. He is likely to become a steady smoker, and nicotine has a direct stimulating effect on the heart.
The maturing man spends more time on his rump and less on his feet. He stands in elevators instead of running upstairs—and exercise involving the legs is one of the most important factors in preserving heart health, according to bicycle fan Paul Dudley White. (The value of walking was dramatized recently by President Johnson—a recovered cardiac patient—when he walked 4� miles around the White House grounds while underexercised newsmen—who called it a "death march"—dropped.) The maturing man is likely to accept weekend golf as his only exercise, but it takes more vigorous action every two or three days to stay in trim. Worst of all, the maturing man is likely to go in for more and more very, very dry martinis and marbled steaks with French fries, and he will probably go right on eating sweet, creamy desserts that he loved as a Little Leaguer. The Burlington conference did not bother itself with the question of whether it is cholesterol in the blood, coming from animal fat, that is mainly responsible for coronary disease and early heart attacks or whether it is some other kind of fatty biochemical compound or something derived from starches. The diet-heart experts have not resolved those questions yet. And for present purposes precise answers are unimportant: too much food, most of it too rich, leads to overweight and a lot of other things that are bad enough for the "loafer's heart."
Then there is the matter of breathing. Professor Vincenzo Lapiccirella of Florence, Italy asserted that a major cause of heart degeneration is the fact that civilized man has abandoned deep, abdominal or "diaphragmatic" breathing in favor of shallow chest breathing. Nobody else at the Vermont conference would go that far, but Dr. Thomas R. Dawber, reporting on a long-term study of heart disease in Framingham, Mass., did suggest that "vital capacity" seems to be an index of heart health. This vital capacity he defined as simply "the largest volume of air you can blow out after taking the deepest breath you can take." It takes no medical detective to see that a man slumped behind an office desk or the wheel of a car is doing little diaphragmatic breathing or anything else to maintain his vital capacity.
Advocates of exercise for the heart had been challenged to prove their case with two sets of matched subjects for comparison. Dr. Daniel Brunner of Tel Aviv University offered convincing proof obtained from the study of 5,300 men and 5,200 women in Israel's collective farm communities, or kibbutzim. These people are ethnically alike, and within each kibbutz they all eat food prepared in a single kitchen. There are no choice cuts for executives. The only differences among these people are in how much they choose to eat and the kind of work they do. The results are clear and striking: heart attacks are two to four times as common among the sedentary managerial and clerical workers as they are among the men and women (carefully matched by age groups) who go out and work in the fields.
Today's sedentary man also takes on a more and more "civilized" pattern of behavior that is foreign to his biological nature as it has evolved down through the ages. When primitive man made his choice between fight and flight, either would serve equally well to work off the adrenaline that his body had just mobilized, in response to signals from his midbrain, as a stimulant for his heart. Civilized man must not display feistiness or fear, so he sits still and takes it. Until the Burlington conference there was no neatly assembled body of evidence to show that just "taking it" in frustrating situations, day after day, may do permanent damage to the heart. Most of the evidence came from laboratory experiments on a menagerie of animals, but it was significant.
If a cat's brain is electrically stimulated often enough to simulate the effects of stress and cause an outpouring of adrenaline, its heart will suffer damage resembling that from reduced blood flow in a man's heart. Some of the cats in this experiment, reported McGill University's Dr. Kenneth I. Melville, died from a clearly defined heart attack.
Dr. Marshall E. Groover Jr., noted for his earlier work with aging Air Force officers, had been puzzled by streaks of dead tissue in the heart muscles of Kenya baboons. Then it was realized that the heart damage was related to the date the animal was trapped. Being trapped subjected the savage simian to an emotional storm for which he had no outlet. Transfer from the trap to a handling cage brought another storm. This, said Dr. Groover, may be "related to the mechanisms in the young executive who is caught in an emotional trap and cannot balance his nervous system by physical activity such as running or fighting."
Modern stress seems to be increasingly damaging, suggested Western Australia's Dr. Salek Mine, because it is more likely to be rational and intellectual rather than emotional. He compared a doctor, called out in the middle of the night to see a patient, and a mother awakened at the same hour by the cry of a sick child. The doctor knows what he has to do, because it is his duty, but this is a rational decision without emotional backing. The mother, on the other hand, feels what she must do, and she does it unthinkingly. Her stress is greater, but when she responds in the only way possible she relieves it. The doctor's less severe stress has no such self-liquidating feature.
Underlying all of civilized man's problems in both keeping fit and reacting to the stresses that he has devised for himself is the fact that nature endowed him with two types of muscles and two types of nerves. In each case, one set is under voluntary, conscious control. A signal from the brain through the voluntary nervous system makes a voluntary muscle contract at will, whether to play arpeggios on the piano or to pitch a ball. The involuntary or automatic ("autonomic" to medical men) nervous system sends signals, by instinctive or reflexive action, to many organs and hormone-producing glands. And it is the automatic nervous system, beyond conscious control, that regulates the heart, a muscle beyond conscious control, as are the muscle linings of the arteries. You cannot direct your heart to beat slower or faster. The intricacies of these automatic control systems are forbiddingly complex and their technicalities took up much of the time at the Burlington conference. But of down-to-earth, practical value is what the reports said can be done to avert, minimize or even to repair the damaging effects on the heart and arteries from neglect (meaning underexercise) and abuse (meaning exposure to unmanageable stress).