The Role of Psychology
The sophisticated machinery that keeps the heart functioning is strongly influenced by the brain and central nervous system-particularly the sympathetic nervous system, which controls stress responses, and the autonomic nervous system, which makes sure vital organs keep working to maintain life. Thus, an important question driving risk-factor research is how we can use nervous system activity and the psychological forces that so strongly affect it as bases for determining who is most prone to heart attack.
Since researchers have long recognized that a family history of heart attack, heart pain, or other heart problems-particularly in blood relatives before age 60-is important in assessing a patient’s risk, it seems reasonable to suggest that specific conditions passed down through the generations deserve a careful look. One issue that is just starting to receive the kind of attention it warrants is the neurological wiring particular individuals may have inherited. Experimental evidence has shown some men and women who may be subject to heart attack apparently have nervous systems set on high. Stress expert and cardiologist Robert Eliot of Phoenix and his colleagues have done pioneering studies measuring heart and blood pressure responses to stressful situations. They have been able to identify some of their subjects as “hot reactors.”
Cardiologist Rodman D. Starke, senior staff physician at the American Heart Association, agrees that such individuals may be prone to heart attack, and adds that the people who respond badly to stress are those who “find it wherever [they] go-at home, in the car at red lights, in a line at the supermarket.”
Research by a team from Ohio State University led by psychology professor Tilmer Engebretson suggests that anger, in particular, is a dangerous emotion. Engebretson and his colleagues, who tracked anger characteristics and cholesterol levels in 116 middle-aged male airplane pilots, found large differences between those categorized as “flexible” and those who seemed overwhelmed by their anger and acted in extreme ways. Men judged to have the most trouble with anger registered total cholesterol levels about 40 points higher than normal, and levels of artery-clogging LDLs about 30 points higher than normal.
A good case can be made that depression poses another serious threat to the heart. About 70 percent of people who have had a heart attack suffer depression-often severe depression-in the year afterward, and patients with severe depression that goes untreated have about twice as many heart attacks during that first year, according to Robert Carney, a psychiatrist at Washington University in St. Louis. “There are now six published studies that show depression increases risk of mortality for patients with coronary disease by several fold,” Carney says. How do these deaths occur? Nobody knows for sure, but depressed patients do show elevated levels of sympathetic nervous system activity.
Findings from psychologist John C. Barefoot of Duke University confirm that depression can be hard on the heart. In early 1996, Barefoot’s group, reporting on a 27-year study of 513 men and women, noted that individuals who scored high on measures of despair, concentration difficulties, weak motivation, and poor self-esteem in 1964 and 1974 had a 70 percent higher risk of heart attack, as well as a 60 percent higher risk of death, compared with those who had low scores. And S. Leonard Syme, an epidemiologist at the University of California at Berkeley, suspects that social isolation might be a heart-attack risk factor as well. He notes that the theme of “interrupted social ties” seems to play through much of the research on heart disease, including his own studies charting the impact of broken family ties on Japanese men and women who have migrated to Hawaii and then to the San Francisco Bay Area. His subjects experienced a rise in heart attacks and heart attack deaths when they moved into Westernized societies, and he speculates that while some of the increase may be attributable to changes in their diets, psychological factors, including loss of contact with loved ones, may be implicated as well.
Finally, job stress could be a crucial factor in determining heart-attack risk. Workplace studies show that employees who feel the most stress are not top executives, as some people might expect, but rather middle managers intent on climbing the corporate ladder. And at the DuPont Corp. in Wilmington, Del., where primary prevention programs and healthier lifestyles are thought to be largely responsible for a decrease in heart attack deaths, corporate medical researchers have discovered that the drop in mortality was about 38 percent in salaried employees with job security but only 18 percent in hourly employees who were more subject to layoffs. Yet another job-stress risk factor for coronary disease might be characterized as situations of “high demand and low control.” Studies of telephone operators working at computer terminals and given only so many seconds to look up a phone number show that a significant number reported chest pain during the experience.
Research on the central nervous system has also provided clues about what specific circumstances precipitate heart attack in those who have already been identified as high risk according to traditional criteria. Cardiologist James Muller of the University of Kentucky in Lexington believes certain triggers act through the nervous system of a susceptible person. He and other scientists theorize that pulling one of these triggers sets a specific sequence of events in motion. First, blood pressure surges, constricting arteries. Then a vulnerable plaque breaks open. This plaque rupture is followed rapidly by formation of a blood clot, and the total blocking of blood flow through the artery. The result is a heart attack.
Heavy exertion such as snow shoveling is one trigger, because it stresses the autonomic nervous system and puts an unusual physical workload on the heart. Another potential trigger is any disturbance in bodily rhythms, he says, noting that more heart attacks happen in the morning, particularly after getting out of bed, and that more happen on Monday than on any other day of the week. The third trigger Muller has identified is fear. Its effects surfaced dramatically in Los Angeles during an earthquake on January 17, 1996, he points out. When it hit, “an enormous peak in coronary deaths” occurred, because “the whole population was exposed at the same time.”