''HE was on the faculty at Harvard, but when he went to Harvard Square to get a cab, no one would pick him up - because he was black,'' said Dr. Dean Ornish, a physician who was treating the man for hypertension.
''He was an hour late for his appointment with me. When I took his blood pressure, it was somewhere around 190/110, much higher than usual,'' said Dr. Ornish, who is now director of a program for treating heart disease in Sausalito, Calif. ''He was angry, but it was a resigned anger, as if to say this was not the first time this had happened to him.''
It is precisely that steady, subdued anger that many practicing physicians and a few scientific studies are now pointing to as a significant reason that hypertension, or high blood pressure, is twice as common in American blacks as whites. The new evidence suggests that dangerously high blood pressure is a hidden cost of racial prejudice for at least some blacks.
''If there were no racism in America, hypertension would be less of a problem among blacks,'' said Dr. Elijah Saunders, a cardiologist at the University of Maryland Medical School and co-author of ''Hypertension in Blacks'' (Year Book Medical Publishers), a leading textbook in the field. ''Hypertension is at near-epidemic proportions among blacks and is chiefly responsible for their high mortality rates from heart and kidney disease and stroke.''
Some Remain Skeptical
''It makes sense to me that racism and black rage are emotional stressors that could worsen any physiological tendency toward hypertension,'' Dr. Saunders said. But the evidence has yet to convince other experts. ''It's an intriguing idea, but it's difficult to attribute much of the hypertension in blacks to anger,'' said Dr. Clarence Grim, chief of the hypertension research unit at the Martin Luther King Jr. Hospital in Los Angeles, who said he believed that genetic and physiological factors play the major role.
Federal health officials say the evidence is uncertain. ''Folks have talked about anger and hypertension in blacks, but there are so many rival hypotheses about blacks' high blood pressure that it's hard to sort out exactly what's going on,'' said Dr. Ed Roccella, coordinator of the National High Blood Pressure Education Program of the National Heart, Lung and Blood Institute. ''So far as I know, there's not strong evidence either way yet.''
Hypertension is a complex condition, with no single cause.Being overweight, a high salt diet and drinking alcohol heavily are the main known risk factors, according to a 1988 study at the National Heart, Lung and Blood Institute.
The possibility that black anger at racism may account for a meaningful portion of the difference in rates of hypertension between blacks and whites, while intuitively sensible to some physicians, has been discounted by many scientists for lack of research evidence.
But in the last few years supporting evidence has grown, including several crucial studies published in the last year. Taken together they build a plausiblescientific explanation for the higher incidence of hypertension among blacks.
Findings of Studies
Among major findings are these:
* People who tend to suppress their anger, both black and white, have higher blood pressure than normal, as has been shown in dozens of studies over the years.
* Some blacks appear to have a greater genetic or physiological susceptibility to high blood pressure than do whites.
* Perhaps a quarter of all blacks retain sodium in their kidneys while under emotional stress, a reaction that raises the blood pressure, according to recent findings, some not yet published.
* Racism is a particularly potent trigger of anger and of high blood pressure in blacks, according to detailed interviews by psychologists with black men, and the clinical experience of doctors who treat black patients.
Link Is Discovered
The first demonstration that racism sets off a greater blood pressure rise than other kinds of anger came from a small study, published last month in Health Psychology, by Kathleen Lawler, a psychologist at the University of Tennessee, with Cheryl Armstead, a graduate student at St. Louis University. The researchers showed 27 black college students scenes from movies portraying racial incidents, other anger-provoking scenes and neutral scenes. For example, from the film ''Places in the Heart,'' the clips depicted a racist scene portrayingan attack on a black farmer by the Ku Klux Klan; an anger-provoking scene, in which a white banker threatens to foreclose on a mortgage and seize a white woman's farm; and a neutral scene, a man talking to a child. In response to the racist scenes, the blacks' diastolic blood pressure rose on average by three points. But in response to the anger-provoking scenes, it rose only one point.
Although the blood pressures did not rise into the range considered hypertension, the reseachers say that such sharp rises indicate a hyperreactive blood pressure, which, if continually provoked over several years, can become a dangerous combination with other risk factors for hypertension, such as obesity or salt retention.
Although there have been relatively few studies investigating the role of racism in hypertension, many physicians who treat blacks for hypertension say the link between black anger at racism and blood pressure problems is obvious in some cases.
''One of my patients was a 45-year-old black woman who had worked in a bank for 15 years,'' said Dr. Shirley Brown, an internist at the University of California Medical School in San Francisco. ''She had no blood pressure problem until she got a supervisor who she felt was racially prejudiced. She came in for her annual physical a few weeks after her new supervisor took over, and I noticed her blood pressure was getting high.''
'Seething With Anger'
Dr. Brown added, ''She told me that she was seething with anger at her supervisor. Over the next three months it rose steadily, to the point where she developed hypertension that required medication.''
''Whites just really don't understand what it's like to be black in America,'' said Dr. Brown. ''As a black, slights are part of daily life.''
''Blacks seem to be in a double-bind with their anger at racism,'' said Ernest Johnson, a psychologist at the University of Houston. ''Because of racial slights and the like, they experience provocation more often than whites, but because of the fear of retaliation if they express anger openly - they may lose a job, for instance - they often suppress it.''
''When I looked at anger and blood pressure in a thousand 10th-graders in Tampa,'' Dr. Johnson said, ''I found that the black kids were angrier than the whites, but that they suppressed their hostility more. The higher the level of suppressed hostility, the higher was their blood pressure.
''And in interviews with black men about the sources of stress in their lives, the most frequently cited is trouble at work, which they believe is due to racism,'' Dr. Johnson said. ''Their blood pressure rises while they are talking about it.''
'A Deadly Biology'
Dr. Johnson added, ''There's a deadly biology when you have continually suppressed anger along with other risk factors.''
One risk factor that is about three times more common in blacks than in whites is the tendency for the kidneys to excrete salt more slowly under stress, according to new findings by Kathleen Light, a physiologist at the University of North Carolina.
In most people the kidneys speed up sodium excretion under stress, thus helping keep blood pressure low. Slowing down sodium excretion under stress raises blood pressure.
''This is a maladaptive response,'' said Dr. Light. ''This stress reactivity pattern, over years, can lead to hypertension.''
Dr. Light found that about a quarter of blacks tend to retain sodium under stress, a trait she believes is inherited.
The pattern of sodium retention under stress, Dr. Light found, runs in families that are more prone to hypertension. ''Given a genetic tendency toward hypertension, emotional stress speeds up the rate at which hypertension will develop,'' she said.
Another factor in the high rate of hypertension among blacks is a higher rate of obesity, especially among women. Both tendencies, toward retaining sodium under stress and toward obesity, are largely independent of diet in blacks, although eating habits can worsen their effects, said Dr. Grim. Though a skeptic on the significance of anger in hypertension, Dr. Grim said it might play a role in some blacks. ''Given the genetic propensity, chronic anger might sometimes bring out hypertension that would not develop otherwise,'' he said.