For many people, stress is part of everyday life. The demands of work, family, and other quotidian pressures can leave one feeling angry, agitated, anxious, downtrodden, or burned out.
While these kinds of day-to-day challenges are often described as mild forms of stress, the reality is that some people will experience them more often and more significantly than others. And there’s mounting evidence linking these and other forms of stress to heart-related health problems.
“We know from several studies in different populations that emotional and psychological stress is associated with an increased likelihood of developing and dying of cardiovascular disease,” says Dr. Beth Cohen, a stress researcher and professor of medicine at the University of California, San Francisco.
For example, research on stress in the workplace has found that people who are under regular strain or who work long hours are up to 40% more likely than their less-taxed counterparts to eventually develop heart disease or stroke. “There are also studies looking at what we call perceived stress, which is the amount of stress a person reports feeling, regardless of cause,” Cohen says. There again, research has found that people who report feeling a lot of stress are at elevated risk for cardiovascular problems down the road.
Meanwhile, some of Cohen’s work has examined the health effects of stress that stem from deeply traumatic experiences—such as those related to military combat service or interpersonal violence. She says post-traumatic stress disorder (PTSD) and other stress-related disorders are associated with increased cardiovascular disease risks.
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But while stress appears to be a major risk factor for heart trouble, there’s a lot about the relationship between stress and heart health that experts are still sorting out. For example, how much stress is too much? “Not all challenging or stressful situations are unhealthy,” Cohen says. “Short-term stress in specific situations, such as working to overcome a difficulty, may actually be beneficial.” Another lingering question: Does stress itself damage the heart, or does stress lead to other things (smoking, poor sleep, an unhealthy diet) that cause the bulk of the harm? These are the types of questions that science has not fully answered.
Untangling the exact relationship between stress and health problems—including heart disease, but also other stress-related conditions such as Type 2 diabetes—is now the goal of research teams across the world. They’ve made progress in showing how stress may change a person—both inside and out—in ways that could contribute to heart trouble.
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Defining stress
In order to understand the negative effects of stress, medical researchers must first define what it means to be “stressed.” That’s easier said than done.
“There’s the lay-person idea of stress, but defining it more scientifically is challenging,” says Dr. Ian Kronish, an associate professor of medicine and associate director of the Center for Behavioral Cardiovascular Health at Columbia University in New York.
For example, some researchers have defined stress as “[a]ny physical or psychological stimuli that disrupt homeostasis.” By this broad definition, watching a suspenseful TV show or hurrying to an appointment are both forms of stress. Both are likely to raise a person’s heart rate and blood pressure in measurable ways. But most experts, like laypeople, recognize that these fleeting periods of stress probably aren’t the kinds that contribute to heart problems.
Another definition of stress is one that encompasses experiences or events that lead to unhelpful changes within the body’s stress-response system. It’s these disruptive forms of stress, Kronish says, that may contribute to heart disease and other health issues. These forms of stress are often sorted into two types: acute stress and chronic stress.
Acute stressors are experiences that lead to very intense activation of the body’s fight-or-flight response. “These are events where the demands of the situation outstrip a person’s resources to handle them,” Kronish says. “Living through a major disaster, whether from natural causes or something like a terrorist event, could be the kind of acute stress that leads to disruptions within these internal systems.” Chronic stress, meanwhile, refers to stressful experiences that may not pose an immediate threat to someone’s health, but that happen regularly and persist for long periods of time. Working in a hectic and draining profession is one example of a chronic stressor that, over time, could lead to perturbations of the body’s stress-response system.
While acute and chronic stress may seem like straightforward concepts, nailing down when and how they harm a person’s health is difficult. Different people will respond to the same stressful situation in different ways; not all veterans with combat experience develop PTSD, and not all people who work in demanding professions develop adverse health effects. There’s also evidence that other lifestyle or environmental factors—such as a person’s exercise habits, their diet, and their social relationships—can help determine whether stress leads to health problems. “When I try to draw this out for people, it ends up looking like a big spider web of connections,” Cohen says. “All of these other things that are important to a person’s psychological and cardiovascular health may affect how they’re impacted by stress.”
It has also been a challenge for researchers to measure stress. “With stress, we don’t have something like blood pressure where I can sit you down and measure it and know exactly what it means,” Cohen says. Likewise, when someone with a history of stress develops heart trouble, there is currently no way for experts to determine whether stress caused that person’s health problems. “We don’t have a test that can tell whether your heart has been impacted negatively by stress,” Kronish says.
In an effort to address these and other gaps, researchers have focused much of their attention on mapping out the underlying connections between stress and health. That work has revealed how acute and chronic stress may contribute to heart trouble, diabetes, and other health problems.
The stress-heart connection
The human body reacts to stress in predictable ways. Blood pressure and heart rate increase, while breathing becomes shallow and rapid. Muscles grow tense and blood sugar levels rise. Alertness and attention sharpen. This all happens because stress-related hormones are circulating throughout the brain and body, ramping up activity in the sympathetic nervous system (SNS) and preparing the entire organism to respond to any potential threats. While SNS activation is the kind of stress a person can feel, a lot more is going on inside them. In fact, stress affects the operation of every organ and system in the body, including the immune system.
All of this is normal and healthy. The body is made to manage stress, and, typically, it will recover from periods of stress without any lingering ill-effects. But in those situations when a stressful event is very severe, or when stress lingers for long periods of time, changes may occur that threaten the heart. “Increases in blood pressure, which can be initiated by stress, will increase pressure on the walls of blood vessels, and can therefore lead to cardiovascular damage,” says Dr. Amgad Makaryus, a cardiologist and professor at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell Health in New York.
The effect stress has on blood pressure is just one of many theorized ways that stress may lead to heart trouble. “With stress, it’s difficult to pinpoint the exact way it’s doing damage, but we know one of the end products of stress is inflammation,” Makaryus says. While stress usually leads to temporary increases in inflammatory activity, chronic stress can produce persistent low-grade inflammation. This sort of simmering, all-the-time inflammation has been tied to heart disease, but also to Type 2 diabetes, depression, and other illnesses of the mind and body.
While there’s good evidence supporting the theory that too much stress damages the body via heightened inflammation and other forms of internal dysregulation, experts say there are still a lot of details to be worked out. “The field is still trying to untangle the various biological and behavioral pathways that may connect stress and cardiovascular health,” Kronish notes. His group has spent a lot of time looking at the ways stress changes a person’s behavior in ways that may lead to health problems. He says stress motivates some people to take better care of themselves, but it can also lead people to forgo exercise and social gatherings, to smoke or drink more than they otherwise would, and to adopt other habits that imperil their health. “Sleep is another pathway that might connect stress to poor cardiovascular outcomes,” he says. There’s evidence that stressed people tend to sleep poorly, and a persistent lack of sleep has been associated with a wide assortment of health problems.
Untangling all these different stress-related harms—both the biological and the behavioral—is no easy task. They’re likely all interconnected. “People talk a lot about a dysregulated stress system, but my sense is it’s a more complicated story,” Kronish says. “There are so many factors to tease apart.”
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How to reduce your risks
Stress appears to threaten the heart in numerous ways. Safeguarding the heart from that assault may require a multi-pronged defensive strategy, experts agree. “People hear that stress is bad for the heart, and so they should do things to reduce stress,” Kronish says. “But the truth is we don’t have a grand slam stress-reducing intervention that we know will protect the heart from stress in all people.”
For example, psychotherapy has shown promise for the reduction of both stress and its attendant heart risks, and Cohen recommends it for people with PTSD and other stress-related mental health conditions, such as anxiety, depression, and trouble sleeping. But the evidence supporting its protective benefits for the heart is inconsistent. “Some trials have looked at psychotherapy and stress reduction techniques,” she says. “They’ve consistently led to better mental health outcomes, but they’ve had mixed evidence in terms of whether they reduce heart disease risk.”
Meanwhile, Makaryus says medication-based treatments aren’t the answer—at least not yet. “Medications are a big part of cardiovascular disease treatment, but we don’t have an easy pill that will solve this,” he says of stress-related heart trouble. “I think the key is prevention.”
It may not be surprising, but he and others say the time-tested elements of a healthy lifestyle—regular exercise, a proper diet, good sleep, and time spent with friends—can help a person recover from stress and reduce their risks for stress-related health problems. “Many people deal with stress by connecting with family and friends, or connecting with a spiritual group,” Cohen says. Leaning on other people for support—as opposed to isolating yourself and dealing with stress on your own—seems to be one of the best ways to reduce its harms, she says.
For many of us, stress is inescapable. But we all have the power to eat better, exercise, and engage in other healthy activities that appear to help limit the harms of stress. “There are mysteries left to unravel,” Cohen adds, “but we already know many ways how to preserve and protect cardiovascular health.”