This is the first statistics-based study, and the largest of its kind, which indicates that fear induced by consistent exposure to the threat of terror can lead to negative health consequences and increase risk of mortality, researchers said.
Researchers from the Hebrew University of Jerusalem and colleagues examined factors affecting resting heart rates, and studied how these rates changed over the years during annual checkups of healthy Israeli subjects.
They studied 17,300 healthy subjects, 10,972 men and 6,408 women, who underwent an annual general medical exam including blood tests, heart rate and stress tests at the Tel Aviv Medical Center each year from 2002 to 2013.
By combining the medical exam data with the questionnaire responses, the researchers found that resting heart rate was affected by physiological characteristics, such as level of physical fitness and inflammation index reflecting the activity of the immune system.
Researchers found that fear of terror was a major contributor to annual increases in resting heart rate, with 4.1 percent of 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 subjects 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.
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.
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 and which 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, and thus reduces the body's ability to defend itself from a heart attack, leading to a greater chance of dying.
The researchers also found that levels of C-reactive protein, a biomarker for inflammation, were elevated in those volunteers 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 thus increase the risk of mortality, researchers said.

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