The amygdala is a region in the brain that is particularly susceptible to stress. Heightened activity in the amygdala has previously been linked to depression, anxiety, post-traumatic stress disorder, and emotion regulation, but has yet to be considered as a risk factor for heart disease. In addition to stress, studies show that arterial inflammation is a known risk factor for cardiovascular illness. Prior animal studies also point to a link between chronic stress and alterations of bone marrow and spleen activity, however these linkages have not been tested in humans.
The link between perceived stress, amygdala activity, and heart disease
In this study, 293 participants age 30 years and older (median age 55 years) with no prior diagnosis of heart disease or cancer underwent PET/CT scanning to record their brain, spleen, and bone marrow activity, and arterial inflammation. They were then followed for an average of 3.7 years. A total of 22 study participants were diagnosed with cardiovascular disease within the follow up period (2.7-4.8 years). Analyses revealed that heightened activity of the amygdala was associated with increased arterial inflammation, heightened bone marrow activity, and an elevated risk for cardiovascular disease. An examination of a cross-section of participants further showed a relationship between perceived stress and heart disease risk. Specifically, higher participant ratings of perceived stress were significantly correlated with greater amygdala activity, arterial inflammation, and C-reactive protein (CPR) levels. (CRP is a known biomarker of stress). This is the first study to provide evidence of the link between perceived stress, heightened amygdala activation, known cardiovascular disease risk factors, and the onset of heart disease. Findings suggest that how the mind, body, and brain perceive and respond to stress may have direct bearing on the onset of cardiovascular illness.
Mindfulness reduces stress and heart disease risk
A comprehensive review and meta-analysis published in Complementary Therapies in Clinical Practice in 2016 provides convincing evidence that practices such as meditation and yoga are highly beneficial for reducing chronic stress. This review linked regular contemplative practice with reduced blood pressure and cholesterol values, decreased waist circumference, and decreased heart and respiratory rates, suggesting that these practices may benefit all those looking to prevent heart disease, or ameliorate its effects. Indeed, the scientific evidence of mindfulness programs such as Mindfulness-Based Stress Reduction and Mindfulness-Based Cognitive Therapy for reducing cardiovascular disease risk factors is building, with studies demonstrating links between mindfulness practice and reductions in heart disease risk factors such as chronic stress, hypertension, poor type 1 and 2 diabetes regulation, smoking, and obesity-related eating behaviors. This may be attributed to the fact that practices like meditation improve attentional control, emotion regulation, and self-awareness, all of which are important contributors to the maintenance of a healthy lifestyle. Although more research is needed to better understand why and how mindfulness practices benefit cardiovascular health, these studies suggest that contemplative practices may decrease the risk for heart disease and increase overall well-being.
