Thursday, May 8, 2014

New study sheds light on the connection between stress and heart disease

A new study in the journal Biological Psychiatry has identified a link between chronic stress and heart disease, and you may not be surprised to learn that this link is inflammation.  The study looked at activity in a part of the brain that helps to regulate emotion called the dorsal anterior cingulate cortex(dACC) and levels of inflammation in the body.  The researchers found that increased activation of the dACC led to higher levels of the inflammatory molecule IL-6 and these higher levels of IL-6 corresponded with more plaque accumulation on artery walls.  Let's take a look at what all of this means.

To fully understand what this means, we first have to discuss something that is regulated by the dACC called cognitive reappraisal.  Cognitive reappraisal is a method of regulating the emotional response to stimuli.  If this sounds familiar, it's very similar to what one tries to achieve while practicing mindfulness meditation.  The problem is, cognitive reappraisal can be either positive or negative.  If a stimulus causes enhanced activation of the dACC but this emotion does not make it to the amygdala to generate an emotional response, that's a positive thing.  If a stimulus continually activates the dACC but also activates the amygdala constantly, that leads to a constant emotional response and chronic stress.

In this study, they found that constantly reappraising a stressful situation caused increased activity in the dACC which increased inflammation.  Since this area of the brain helps control many autonomic processes, it's not surprising that activation of this area of the brain can modulate the immune response.  Furthermore, the dACC is associated with anxiety and OCD-type behaviors in so much that severing the area has been shown to benefit people with OCD not responsive to medications(1).

Obviously you shouldn't severe your dACC, but this study points to the importance of reducing stress and letting things go to reduce heart disease risk.  The increased level of IL-6, an inflammatory cytokine highly associated with heart disease and Type 2 diabetes, is likely a large player in the relationship between stress and health.  In my next blog, I'll go over some of the physical warning signs that you may be experiencing chronic stress.