How is anger linked to heart attacks and strokes?

In 1959, researchers first suggested that people who were highly competitive, ambitious, work-driven, time-conscious, and aggressive (type “A” behaviour) were at higher risk of experiencing a cardiovascular event. This hypothesis generated great interest, and several researchers have since studied the association between psychological factors and cardiovascular events.

Anger has been associated with an increased risk of cardiovascular events (heart attack, stroke) in several previous studies, but the mechanism behind this phenomenon remains unknown (see here, here, and here). Researchers recently examined the effects of three negative emotions (anger, anxiety, and sadness) on the health of the endothelium, the layer of cells that lines blood vessels. The randomized, controlled study included 280 participants aged 18 to 73 who had no history of high blood pressure, diabetes, metabolic imbalance, or mood disorder. Participants were randomly assigned to three groups that were exposed to conditions designed to elicit specific emotions:

• Anger and anxiety: Participants were asked to recall an event that made them angry or anxious and talk about it for 8 minutes.
• Depressive state: Participants were asked to read sentences that were increasingly sad for 8 minutes (Velten Mood Induction Procedure).
• Neutral state: Participants in this control group were asked to count aloud for 8 minutes.

The researchers measured the blood flow of each of the participants using an inflated cuff on the dominant arm, an intravenous catheter, and a finger-worn probe, immediately after the induction of the negative emotion or the performance of the neutral task and after 3, 40, 70, and 100 minutes. Since the simple act of talking can affect blood vessels, participants in the control group were asked to talk (count) without eliciting either negative or positive emotions.

Anger significantly reduced blood vessel dilation, compared with the control group. Two other negative emotions, anxiety and sadness, had no significant effect on endothelial health. The adverse effect of anger lasted for up to 40 minutes, before returning to normal. The authors of the study believe that a person who gets angry often damages his or her arteries continuously, and that over time this could lead to the development of atherosclerosis and cardiovascular diseases.

Healthy blood vessels undergo the process of vasodilation on a regular basis, to increase blood flow and thus allow oxygen and nutrients to be transported through the body. Impaired vasodilation, caused by the loss of endothelial function, promotes several processes that lead to the accumulation of plaque in the arteries, i.e. atherosclerosis.

The underlying biological mechanisms by which anger disrupts endothelium-dependent vasodilation remain unknown. Possible mechanisms include the following:

• activation of the sympathetic nervous system, which has previously been associated with disturbances in endothelium-dependent vasodilation;
• dysregulation of the hypothalamic-pituitary-adrenal axis;

• a decrease in the bioavailability of nitric oxide;
• an increase in oxidative stress;
• increased inflammation of the arteries;
• an increase in endothelin-1 (a vasoconstrictor neuropeptide secreted by the endothelium), which has previously been associated with psychological stress.

One important takeaway from this study is that not all negative emotions are created equal when it comes to their effects on the cardiovascular system. In light of the results of this study, clinicians may want to inform their patients about different anger management strategies to promote good cardiovascular health, particularly for patients who experience chest discomfort or pain when they are angry or stressed.