A new study has found that long-term exposure to the threat of terrorism can elevate people’s resting heart rates and increase their risk of dying.
The study of more than 17,000 Israelis is the first statistics-based study, and the largest of its kind, that indicates that fear induced by consistent exposure to the threat of terrorism can lead to negative health consequences and increase the risk of mortality, according to researchers at The Hebrew University of Jerusalem.
Elevated resting heart rate is a predictor of death from cardiovascular disease and death across all causes. As people age, the resting heart rate typically decreases from year to year, and people whose heart rate actually increases annually are more susceptible than others to heart attacks and strokes.
According to the researchers, it is well-documented that international terror outbreaks involve mass psychological trauma, leading to long-term mental health risks. Additionally, previous studies have shown that in the short term, sudden stressful events, such as earthquakes, can increase a person’s heart rate and their risk of having a heart attack.
However, little was known about whether the long-term exposure to the threat of terror can lead to physical health risks, the researchers noted.
That led them to examined the factors affecting basal (resting) heart rates, and studied how these rates changed over the years during annual checkups of healthy Israeli people. Israel has been exposed to the repeated stress of multiple wars and terror attacks for more than 60 years, with a major impact on the entire society, the researchers noted.
Drs. Hermona Soreq, Shani Shenhar-Tsarfaty and Yaacov Ritov studied 17,300 healthy Israelis who underwent a medical exam including blood tests, heart rate, and stress tests at the Tel Aviv Medical Center each year.
The 10,972 men and 6,408 women in the study were healthy employees getting their routine health examinations during the years 2002-2013. The data was collected as part of the Tel Aviv Medical Center Inflammation Survey (TAMCIS).
The researchers asked each person in the study to fill out a questionnaire that covered a wide range of occupational, psychological and physical factors, including body mass index, blood pressure, fitness, smoking, psychological well-being, anxiety and fear of terror.
“We wanted to test whether fear of terrorism can predict an increase in pulse rate and increased risk of death,” said Soreq.
By combining the medical exam data with the questionnaire responses, the researchers found that basal heart rate was affected by physiological characteristics, such as level of physical fitness and inflammation index reflecting the activity of the immune system.
In contrast, an ongoing increase in heart rate was also influenced by psychological characteristics such as fear of terrorism, according to the study’s findings.
Through a statistical analysis of 325 different parameters, the researchers found that fear of terror was a major contributor to annual increases in resting heart rate, with 4.1 percent of the study participants suffering from an elevated fear of terror that predicted an increase in their resting heart rates.
While a heartbeat of 60 beat per minute is normal, an increase of up to 70-80 beats per minute was observed in people who exhibited an increased fear of terrorism. In other words, for people with an elevated fear of terror, the heart beats faster and the associated risk of heart disease is higher, the researchers explain.
The researchers also examined how the brain alerts the body to the expectation of danger. They administered a blood test to examine the function of acetylcholine, a neurotransmitter involved in responses to stress, which also acts as a brake to the inflammatory response.
The results showed that the fear of terror leads to a decline in the function of acetylcholine, reducing the body’s ability to defend itself from a heart attack, leading to a greater chance of dying.
“We found that fear of terrorism and existential anxiety may disrupt the control processes using acetylcholine, causing a chronic accelerated heart rate. Together with inflammation, these changes are associated with increased risk of heart attack and stroke,” Soreq said.
The researchers also found that levels of C-reactive protein, a biomarker for inflammation, were elevated in those who fear terror and show escalated pulse. This finding further suggests that long-term exposure to terror threats may combine with inflammation to elevate resting heart rates and increase the risk of mortality, according to the researchers.
The researchers suggest that since information on heart rate and its time-related changes is easy to follow, the findings may be useful in identifying asymptomatic people who could benefit from prevention measures designed to limit increases in cardiovascular mortality risk. These could include vagal stimulation, anti-inflammatory or anti-cholinesterase medications or physical activity.
The study was published in the Proceedings of the National Academy of Sciences.