Jerusalem — Several studies have documented the negative impact anxiety related to terrorism and armed conflict can have on mental health, but only one statistical study has assessed the physical toll long-term terrorism-related stress can have on the heart.
That study, published by Hebrew University researchers, found that terrorism-related fears can increase people’s resting heart rate and boost their risk of dying.
Published a year ago, the study’s findings have taken on a new urgency due to the latest wave of Palestinian terror “and the emergence of terror as a worldwide phenomenon,” Hermona Soreq, a Hebrew University professor of molecular neuroscience and the study’s lead researcher, told The Jewish Week.
Along with professor Yaacov Ritov, a Hebrew University statistician, Soreq analyzed the health records of 17,300 apparently healthy Israeli volunteers who underwent thorough check-ups from 2002 to 2013 at the Tel Aviv Medical Center.
Those employment-related checkups, which formed the basis of the Tel Aviv Medical Center Inflammation Survey, measured more than 300 health indicators and included a questionnaire with a wide-ranging list of questions. One of those questions asked participants to rate their fear of terror attacks from 1 to 5, with 5 being the highest level.
Soreq said her team was anxious to analyze the Medical Center data because it offered a cross-section of the Israeli population, which unfortunately has a great deal of experience coping with terror.
“Israel has a population that has been chronically exposed to stressful conditions for several decades, and here are 17,000 people from different communities, both Arab and Jewish, religious and secular, men and women.”
Although terror fears aren’t unique to Israel, the researcher said, the public’s decades-long experience with terror threats coupled with the country’s relatively small size and high-quality public medical system, make it the perfect place to assess terror’s impact.
The team searched for data indicating higher-than-normal inflammation markers in the body and a pronounced increase in the basal heart rate (how many heartbeats per minute) “because we know stress and inflammation impact on each other,” Soreq said.
“In normal individuals the resting heart rate should be around 60 heartbeats per minute, give or take. In healthy individuals that rate goes down slightly with age. But there’s a fraction of the population where it goes up instead of down and this is a known risk factor for morbidity. If your heart rate goes up over time it means you could be at higher risk for a stroke or a heart attack.”
The computer-based analysis found that 4.1 percent of those surveyed suffered from an increased heart rate, “and those were exactly the individuals who said they most felt the impact of terror stress,” Soreq said. “The same people who had rated their fears at 5 had greater levels of inflammation and they had 10 to 12 more heartbeats per minute than others.”
While 4.1 percent may seem a small number in a study, Soreq said it’s a worrisome percentage in a population of more than 8 million people.
To determine how the brain tells the body to prepare for stress or trauma, the team tested the amount of acetylcholine, a neurotransmitter in the autonomic nervous system that plays a part in the body’s reaction to tension and stress.
“The results showed that the fear of terror leads to a decline in the function of acetylcholine, and thus reduces the body’s ability to defend itself from a heart attack, leading to a greater chance of dying,” Soreq said in an article on her research published on the Hebrew University’s website.
“We found that fear of terrorism and existential anxiety may disrupt the control processes using acetylcholine, causing a chronically accelerated heart rate. Together with inflammation, these changes are associated with increased risk of heart attack and stroke,” Soreq said.
Levels of C-reactive protein, an inflammation biomarker, were also high in study participants with a higher-than-average heart rate who said they fear terror.
Since the heart/terror study was published, Soreq and her colleagues have embarked on a new study to determine whether there are people whose genome — a person’s complete set of DNA, including all of its genes — dictates his or her risk for stress-related physical health problems. The research is focusing on neurotransmission and how it affects the subjects’ stress-related reactions.
Soreq told The Jewish Week that the subjects of the study, which she could not discuss in depth because it is being prepared for publication, are Israeli soldiers, “who are definitely exposed to much higher stress levels than regular citizens.”
Ultimately, Soreq said, researchers hope to find answers to these questions:
“Would a person who inherited a change in a genome that affects the neurotransmission pathway put them at a higher risk? Can our brains adapt to changes in our genome and overcome the difficulties? Can someone born sensitive overcome that sensitivity and if so, how?”
Soreq, the first woman to serve as dean of the university’s Faculty of Science, said many questions related to the body’s reaction to stressors like war and terror remain, but “once we understand the mechanism we can begin trying to find ways to prevent the disease process.
“Today, unfortunately, this is a worldwide issue,” she said.