Why mental stress can take a toll on the heart

Researchers have found that mental stress can significantly impact the heart, particularly among people with heart disease. When faced with stress, the body typically activates its sympathetic nervous system, increasing heart rate and constricting blood vessels. This prepares the body for a "fight or flight" response. However, for those with heart disease, this response can lead to reduced blood flow to the heart, known as myocardial ischemia, which increases the risk of heart attacks or heart-related deaths.

The study, published in Circulation: Cardiovascular Imaging, highlighted that dysregulation between the sympathetic and parasympathetic nervous systems plays a crucial role. Reduced heart rate variability, which reflects the heart's ability to adjust to stress, was linked to a higher risk of ischemia during stressful situations. This imbalance, termed autonomic dysregulation, indicates that the sympathetic nervous system dominates, while the parasympathetic system, responsible for calming the body, is less active.

During the study, participants underwent a mental stress test involving speech preparation. Those with lower heart rate variability were more likely to experience ischemia compared to those with higher variability. The findings underscored that mental stress affects the heart differently than physical stress, suggesting tailored interventions such as heart rate monitors or stress-reducing techniques could help manage these risks effectively.

Source: National Heart, Lung, and Blood Institute (NHLBI), USA