By A.J.S. Rayl, published on July 1, 2007 - last reviewed on June 9, 2016
The nightmare began in 1996 when Sally Clark's 11-week-old baby, Christopher, was found dead in his Moses basket. Sally and her husband, Steve, both attorneys from Essex, England, decided to have another child. Fourteen months later, baby Harry, 8 weeks old, collapsed in his bouncy chair and died. Sally Clark was accused of killing her babies and summarily thrown in jail. While facing trial for murder, she discovered she was pregnant; that child was taken from her and placed in foster care. Clark was convicted of murder based on faulty testimony and handed two life sentences. The wheels of justice finally turned, and in 2003, Clark was released from prison while the doctor who put her away had his theories discredited and his medical license stripped. Back at home, the barrister found normal life difficult. Suffering bouts of depression, mood swings, and nightmarish memories of her time in jail, she barely left the house. Then, this past March, at age 42, Sally Clark died suddenly of natural causes, officials said.
"She died of a broken heart," her friends told the tabloids, which had covered the Clark saga from the start. Though the exact cause of death is still under investigation, the idea that someone might succumb to prolonged stress and grief has always been provocative. Is it possible? The popular belief has gotten some hefty backup from scientists studying the link between the heart and mind. While not all negative thoughts and feelings are bad for health, specific emotional states, especially stress and depression, have now been linked to heart troubles of all kinds. Evidence is overwhelming that the heart takes a beating after psychic trauma like Clark's, but lesser insults may do us in as well. A bad marriage, an angry or abusive boss, a mugging in the park—all increase risk of heart disease, a bounty of evidence shows. Personality factors like extroversion and optimism can positively impact the cardiovascular system and the health of the heart, while anger and stress can damage the heart and the mind. Some forms of heart disease even trigger the same chemistry found in depression and stress.
In the last couple of years, our understanding of the connection between heart and mind has gathered enormous nuance, detail, and depth. We've long connected depression and anger with heart ailments, but new findings suggest that even mild forms of these states can place us at risk. Other studies now trace the relationship between heart and mind to our days in the womb. We are now identifying the personality types and temperaments that make some people so vulnerable to heart trouble, and we've learned it's not just extreme stress or fear, but also work-related repetition and boredom—often referred to as burnout—that puts us at risk. Finally, we are gaining profound new insight into the biology behind the links: For the first time, researchers are getting to the bottom of the inflammatory process that drives depression, stress, and heart disease—as well as the feedback loops that keep all three so tightly bound. With knowledge comes new hope. The more we know, the more that changes in lifestyle and pre-emptive treatments can reduce risk of cardiovascular disease, still the number one killer in the United States.
The connection between emotional well-being and the heart begins in the womb, when the unborn child's heartbeat pulses in time with that of her mother. Heart-to-heart synchrony continues after birth, when babies' hearts beat rhythmically with mothers and fathers during face-to-face interaction. "This is amazing—that one person can change the other person's physiology without even touching them, just by sensing the rhythm of their heartbeat and breath," says psychologist Ruth Feldman, of Bar-Ilan University in Israel, whose studies have shown that these early interactions lead to easy intimacy later in life. "Synchronized heartbeats are so basic to parent-child communication that they permeate every close human relationship from then on. Having a good synchronous relationship in the first year of life prepares infants to show more empathy and be able to read emotions better," Feldman says.
The converse is also true. When parent-child breathing or heartbeat detach from each other and go out of sync due to things like premature birth or postpartum depression, the impact can be so profound, it may be harder for that person to forge healthy relationships later in life, Feldman adds. It isn't that being out of sync predisposes a baby directly to heart trouble, of course. Rather, the shared rhythm shows just how sensitive the heart is to interpersonal experience and emotional expressions like rejection, anger, acceptance, and love.
As a child grows, the heart remains vulnerable to love, to stressors, and to pain. Even the turbulent events of 9/11 had an impact on young hearts. Psychologist Brooks Gump of the State University of New York at Oswego studied children in upstate New York after the destruction of the towers and found that even though the event was physically distant, it produced changes in children's cardiovascular responses compared to a similar group of children tested before the attacks. "If terrorism affects responses to stress, then chronic threats of terrorism might increase the risk for heart disease," Gump says.
Over time, stress exacts a price, wreaking damage that appears to be cumulative, Harvard psychologist Laura Kubzansky says. That's why stress-prone children are more likely to become stress-prone, at-risk adults.
How can nebulous patterns of thinking and feeling "get inside the body" in a way that alters the outcome of disease? How are heart health and emotion linked?
Many experts say that one key pathway connecting emotion and atherosclerosis is inflammation, the process by which the immune system produces cells and molecules to purge outside invaders. Gregory Miller, a psychologist at the University of British Columbia, has identified inflammation as a "biological superhighway" connecting emotional stress and heart disease in a never-ending loop. In the short term, he explains, stress serves a purpose: By initiating inflammation, it mobilizes the body's immune cells to eliminate infection and heal injury. But when stress is long-lasting, the engine of inflammation can run without end. Over the long term, inflammatory molecules can "spill into the brain, where they may cause apathy, social withdrawal, fatigue, and changes in eating habits." Although the symptoms look very similar to those of depression and are being defined as such, "we're not yet sure if they're the same depression you see in a clinic staffed by psychiatrists," Miller says. Whatever it's ultimately labeled, heart patients who have these depressive symptoms and are not treated for them will see their heart disease progress faster, he adds.
The biological superhighway connecting emotion and the heart runs "two ways," Miller emphasizes. "Chronic stress and events with certain emotional themes can kick off an inflammatory process that leads people down the road to both depression and cardiovascular disease." On the other hand, inflammation can start with heart disease, which then causes stress and eventually depression, he says.
Are you the life of the party or painfully shy? Optimistic or pessimistic? So focused on a task that sirens won't budge you—or distracted by the rustling breeze? It's only recently that we've found a connection between temperament and cardiovascular risk.
For years cardiologists pointed to one high-risk temperament: the hothead, quick to anger and fast to explode. The archetype, a TV miniseries cliche, is the jealous boyfriend or rageful boss who, faced with challenge, turns red, grips his chest, and winds up wired to monitors before the commercial break. At especially high risk is the eruptive person who has what psychologists call "trait anger"—the tendency to get mad with minimal provocation and then respond aggressively at the drop of a hat. In a wide range of studies conducted since 2000, researchers have found that trait anger can predict strokes and atherosclerosis. The angriest people face twice the risk of those with normal temperaments, and cardiovascular problems increase in tandem with the level of anger itself.
These days researchers say that more nuanced personality types may also play some role in heart function and health. Those who are optimistic and friendly, it turns out, may have healthier hearts and less chance of heart trouble than the pessimistic or shy. Harvard's Kubzansky says states like hopelessness and even the tendency to ruminate and worry are associated with heart disease.
In one telling study, Dutch researchers asked young extroverts and introverts to focus on tasks. The extroverted children were more distracted by irrelevant information and had more trouble focusing. Introverts—who inhabited a more circumscribed zone of comfort—ignored the extraneous, and their focus was superior as a result. But even though introverts were better at focusing, their cardiac rhythms showed that they were more heart-stressed when a distraction occurred.
Another recent study shows the value of being trusting. University of Michigan scientists reached that conclusion by rating people according to trust, stress, and depression, and then measuring the presence of three markers of inflammation—fibrinogen, C-reactive protein, and IL-6, all linked with narrowing of the arteries and future heart-disease risk. Higher levels of cynical distrust were associated with higher levels of all three markers, while chronic stress was linked with higher levels of IL-6 and C-reactive protein, and depression was associated with higher levels of IL-6.
If you already have heart disease, depression may put you at grave risk. Duke and University of North Carolina scientists found that congestive heart-failure patients are about 50 percent likelier to die or be hospitalized for their heart condition if they are depressed as well. Duke medical psychologist Andrew Sherwood, the study's lead investigator, says depression can be as important for heart-challenged folks as traditional risk factors like high cholesterol and hypertension. Among the explanations for the findings, says Sherwood, could be the heart's ability to react to everyday stress, or the possibility that depressed patients don't comply with medical treatments or make healthy lifestyle choices in such areas as diet and smoking.
Not everyone with heart disease can point to an emotional trigger—but when emotional factors are at the root, the triggering of a heart attack may be likelier for some. In male patients with heart attacks triggered by emotion like anger or stress, blood pressure and heart activity took longer to return to normal than in those without an emotional prelude to the event, according to Andrew Steptoe, a cardiologist at University College in London. The study shows that some people are more vulnerable to heart attacks "because of the way they respond biologically when confronted with a socially demanding situation," Steptoe says.
If you've ever needed motivation to quit a boring or overwhelming job, new findings from the world of work provide all the incentive you'll need. Nothing embodies overload as dramatically as the firefighter who emerges from a blaze unscathed, only to feel so stressed out that he suffers a heart attack and dies. According to a March 2007 report in the New England Journal of Medicine, most firefighters spend less than 5 percent of their time putting out fires, yet fully a third of all firefighter deaths from coronary artery disease are associated with that activity.
As stress on the job increases, health and longevity can be damaged long-term. Dutch scientists recently reported that flight controllers responsible for 12 aircraft simultaneously (as in busy airports) have faster heart rates and higher blood pressure than those responsible for six planes.
But you need not be fighting fires or averting potential airline collisions to damage your heart. Burnout—emotional exhaustion, physical fatigue, and cognitive weariness—can set in if a job is always stressful or intense, or if you've just been doing it for too long.
The destructive power of burnout is shocking. While it's been traced to psychological problems in the past, says Samuel Melamed, an epidemiologist at the Sackler School of Medicine at Tel Aviv University in Israel, only recently has it been recognized as a risk to the heart. In fact, Melamed has found that people who are burned out have a two- to-threefold higher risk of heart problems, including recurrent myocardial infarction, stroke, coronary-bypass surgery, increase of coronary atherosclerosis, and cardiac death. What's more, the possibility of damage done to the heart by burnout can last up to eight years after that boring or stressful job has come to an end. "The risk is equal to or exceeds that conferred by age, body mass index, smoking, blood pressure, or lipid levels," Melamed says.
Why is burnout so ruinous to the heart? Melamed theorizes that sleep deprivation and physical exhaustion are at the root. He has found that burned-out workers are uncomfortably restless and tense at work. After work, they are so irritable they can't unwind, leaving them sleep-deprived and so exhausted that they become overwhelmed by fatigue.
Her husband died suddenly on a September evening in 1993, and a few hours later she was admitted to an emergency room in Rennes, France. The woman, 70, suffered intense, constrictive chest pain along with sweating, nausea, and vomiting; then she passed out. A couple of years later another woman, age 50, showed up at the same ER in Rennes. Her symptoms were similar and her story also marked by grief: Her son had taken his life just hours before. Both women were treated and both survived—but oddly, in the months thereafter, showed no signs that their heart tissue had been damaged or that they suffered coronary artery disease at all.
Such cases have long puzzled doctors, but in recent years the mystery has been solved. The phenomenon, often provoked by sudden stress or shock like the death of a loved one, causes symptoms that look like a garden variety heart attack, including shortness of breath and chest pain, fluid in the lungs, and, finally, perhaps heart failure. The heart's ability to pump is severely impaired, but the heart tissue itself isn't damaged, nor are the arteries clogged, as is often the case with cardiovascular disease. Instead, as the patient's grief takes hold the apex of the heart, which pumps blood to the left atrium, balloons out and weakens, resulting in abnormal blood flow. Not surprisingly, broken heart is now medically known as apical ballooning syndrome, or stress-induced cardiomyopathy.
"We're recognizing broken heart syndrome with greater frequency here in the U.S.," says Mayo Clinic cardiologist Chet Rihal, who has led the largest review of the condition to date. "This is different than chronic stress, where a person has trouble at work or at home. These mental and physical stresses tend to be caused by severe and sudden shock."
Rihal theorizes that extreme stress might kick up a flood of adrenaline, damaging tiny blood vessels and causing the heart's muscles to shut down. Some people appear especially susceptible: About 10 percent of broken heart patients will have a similar attack again.
Research connecting emotional health and heart health is still in the early stages, but the take-home message is clear: Safeguarding the heart can be as simple as walking away from a fight, quitting a boring job, or working out anger by running around the block. These simple, proactive interventions—if tapped regularly—just might save your life.