Terrorist attacks like the one in Paris this Wednesday can create a climate of national anxiety -- and such a climate may come with health risks that we're not considering, according to recent research from a team at the Hebrew University of Jerusalem. The everyday fear and stress of living with the threat of terrorism has been shown to elevate one's resting heart rate, which can lead to a greater risk of cardiovascular disease and even death.
In the largest statistical analysis of its kind, Hermona Soreq, a professor of molecular neuroscience, examined a group of 17,380 healthy adult Israelis and found that she was able to predict which participants would exhibit an unusual increase in resting heart rate, based on how fearful they were of potential terrorist attacks.
And the findings don't apply only to Israelis or mass attacks from insurgent groups, Soreq notes.
"We believe that the definition [of] 'fear of terror' represents general anxiety, and therefore it is reasonable to extend the implications of our results also for other countries and other types of anxiety," she told The Huffington Post in an email. "However, this must be tested in separate populations and proven in independent studies."
The long-term psychological effects of fear of terrorism, such as anxiety and post-traumatic stress disorder, are well-known, but Soreq hopes her finding will lead to more research about the long-term physical effects. She said that people who are under constant threat of terrorist attacks should be just as vigilant about their long-term health as they are about their safety, and that they should seek help if they notice changes in their resting heart rate.
Soreq and her team analyzed the data of apparently healthy study participants (10,972 men and 6,408 women) who had visited the Tel Aviv Medical Center for routine health exams between 2002 and 2013. In all, the researchers analyzed 325 different metrics, but three were of particular interest to Soreq’s team -- C-reactive protein, which increases when levels of inflammation rise in the body; a brain chemical called acetylcholine; and fear of terrorism, or FOT, which was assessed based on participants' responses to the following statements:
1) Nowadays, I worry about my personal safety.
2) Nowadays, I feel heightened tension when I am in crowded places.
3) I am afraid of a terror strike harming me or my family.
The participants noted, on a scale of one to five, how much they agreed with those statements, and Soreq used those responses to come up with FOT scores for each participant. She found that the 4.1 percent of participants who had high FOT scores also had elevated resting heart rates over time -- which is unusual, because as most people age, their resting heart rate tends to go down. These people also tended to have higher levels of C-reactive protein, which means they had more inflammation in their bodies, and had lower levels of acetylcholine, a neurotransmitter that the body releases when it is trying to tame stress. Soreq linked all of these factors in a statement about the study.
"We found that fear of terrorism and existential anxiety may disrupt the control processes using acetylcholine, causing a chronic accelerated heart rate,” Soreq wrote in the press release. "Together with inflammation, these changes are associated with increased risk of heart attack and stroke."
However, this study only demonstrates a link between FOT and elevated pulse and the other biomarkers, meaning that researchers can’t assume FOT caused people's resting heart rates or levels of inflammation to increase over time. But these are questions Soreq wants to examine in future research, she told HuffPost. She also noted that she’d like to be able to better identify which particular diseases might be exacerbated due to FOT. For now, her study simply suggests that people living under the continuous threat of terrorism should monitor their resting heart rate as part of a regular health assessment.
"The main therapeutic implication is that psychological stress (expressed as fear of terror) can cause long term risk for cardiovascular diseases, so that [individuals] under continuous threat should be aware of such risks and seek medical advice if their pulse gets faster with time,” Soreq wrote to HuffPost. “This study shows the importance of going through routine health tests, because those can show you risks that you never anticipated."
Professor Daphna Canetti of the University of Haifa in Israel has studied the health impacts of terrorism and traumatic events for about a decade, and has also analyzed levels of C-reactive protein and elevated pulse on a large scale. Canetti wasn’t involved in Soreq’s analysis, but she said it raised important issues and agreed with Soreq's assertion that more screening for trauma and PTSD is needed for civilian populations that are constantly under threat -- not just among veterans or soldiers.
"The medical system worldwide has begun to screen for depression, but there is nearly no screening for trauma and PTSD,” Canetti told HuffPost in an email. “Those with clinical or near clinical levels of PTSD need treatment, as all the evidence [suggests] that PTSD is both highly painful and adversive in its own right, and related to health deterioration."
Canetti also said that the emerging body of evidence about how terrorism and conflict affect civilian populations could help steer public policy one day.
“To the extent the population understands that their own soldiers will return with lifelong burdens of disease and that if under attack, they themselves will have these additional health costs, it may influence the balance of public opinion” about how governments wage war, she concluded.
Professor E. Alison Holman of the University of California, Irvine, has published surveys (which do not contain physiologic data) showing that in the wake of the Sept. 11, 2001, terrorist attacks, there was a significant correlation in Americans between high acute stress, the fear of potential terror attacks and the beginning of new cardiovascular symptoms. Holman wasn’t involved in Soreq’s analysis, but said the study’s large sample size, as well as the the hundreds of biomarkers the researchers assessed, offered “fascinating” new insight into how deeply fear affects physical health.
“The authors did a thoughtful approach and analysis for linking the psychological and physiologic correlates potentially related to terrorism,” Holman wrote to HuffPost. "By analyzing measures of physiologic parameters in relation to these psychological (fear of terror, perceived control) and cardiovascular risk factors (inflammation, BMI, etc) they have provided some fascinating new data that I believe are quite telling about how profoundly fear contributes to both mental and physical disease."
However, Holman noted that it would be interesting to map the participants' levels of fear, and their changes in body chemistry over time, in relation to how many terror attacks each person actually experiences during that time. She said this could help to make sure other kinds of life traumas aren’t affecting the results.
"It is important in these kinds of studies to examine ongoing stress/trauma using an assessment that differentiates between terrorism and other types of stressful events, and control for this in the analyses,” Holman explained. "What if there are other things going on in people's lives that are the more immediate explanation for their higher heart rates?"
Soreq's analysis excluded people in therapy for anxiety and depression, but she acknowledged that some participants with pre-existing mental health issues who were not receiving treatment could have flown under the radar and been included in the study. She did try to account for differences in the way individuals manage stress, with questionnaires about perceived control over one's work environment, but she admitted that more work is needed to assess how personal stress management can affect things like the fear of terror.