Frequent exposure to violence may affect teens’ blood pressures and heart rates, Canadian researchers report. Their study findings suggest that exposure to violence may not only have psychological effects, as has been previously demonstrated, but physiological effects as well.
“Real-life exposure to violence has effects not just psychologically, but also on biological systems among adolescents,” study author Dr. Edith Chen, of the University of British Columbia in Vancouver, told Reuters Health.
Previous research found an association between violence exposure and daytime systolic blood pressure (the top number) and nighttime diastolic blood pressure (the bottom number) among adolescents.
Other researchers found that elevated blood pressure, heart rate and other indicators of a poor resting physiological profile in adults may be linked to the development of high blood pressure, coronary artery disease and other conditions. Few studies on the topic have been conducted among children and adolescents, however.
Chen, and co-author Rama Murali, studied 115 students at a public high school in St. Louis, Missouri. The subjects ranged in age from 16 to 19 years, all were healthy and none were taking any heart-related medications.
Blood pressure, heart rate and hormone levels were measured before and after the subjects participated in a stress task and watched a video of serene nature scenes. Students were classified by total observed or experienced violent incidents and by the frequency and intensity of these events.
Higher level of stress hormones
Those who reported experiencing a higher level of violence exhibited higher resting blood pressures and heart rates, and higher levels of the stress hormone cortisol, compared with their peers, the researchers report in the October issue of Annals of Behavioral Medicine. Cortisol, which is released in stressful or dangerous situations, is involved in the “fight or flight” response.
According to Chen, “the associations of greater exposure to violence with elevated resting physiological measures suggests that exposure to violence, over the long-term, might increase health risks for cardiovascular problems such as hypertension and cardiovascular disease later in life.”
Still, the teenagers’ systolic blood pressure reactivity decreased along with increasing reports of total experienced and observed violence, while their heart rate marginally increased along with increasing reports of total experienced violence, the report indicates.
This finding, coupled with the teens’ higher resting systolic blood pressures “suggest that exposure to violence, over time, might take a toll on resting physiological levels, ” Chen said.
“In addition, repeated exposure to violence might 'numb' an adolescent’s biological stress response system, such that when new stressors occur (e.g., the acute lab stressor), their systems do not respond adequately to that stressor,” she added.
Overall, the most pervasive biological effects were seen among teens who more frequently experienced, rather than witnessed, violence. Chen and Murali conclude that “this illustrates the importance of focusing on the health and well being of populations that are exposed to multiple violent events over time, and developing interventions and policies that can alleviate the wear and tear associated with cumulative violent event exposure.”
