How Chronic Stress Provokes Heart Attacks

There are ways to measure acute stress to an individual – urinary epinephrine, nor-epinephrine, dopamine, cortisol, and salivary cortisol, along with standardized symptom questionnaires.  Perhaps the best of these is salivary cortisol levels, as sputum is readily obtainable at even stressful moments.  But how about chronic stress?  Salivary cortisol and other measures reflect a short stress situation, but how can one capture prolonged exposure to stress?  It helps to think of the relationship between a single blood glucose measurement (a snapshot of the glucose load in a diabetic) and the blood HbA1c (the glycated hemoglobin level, which represents the average glucose load over the previous 2-3 months).

A study reported in the journal Stress has found a simple way to measure chronic exposure to stress.  Scientists from Canada and Israel have developed a way of estimating hair cortisol levels, which is a measure of average stress levels in the recent past; thus the proximal 3 cm of hair is considered to represent the circulating cortisol levels over the previous 3 months (hair grows, on average, 1 cm/month).

To test the usefulness of this measurement, the researchers collected hair samples from 56 men who were hospitalized with a heart attack, and from 56 men who were also hospitalized, but not for heart attacks.  Hair cortisol levels were clearly higher in the heart attack patients, although both groups had similar heart attack risk factors, such as high blood pressure, smoking, and a family history of coronary heart disease.  (But cholesterol levels were higher in the heart attack patients.)         

The results of this study suggest that chronic stress, as demonstrated by hair cortisol levels, contribute to the risk of heart attack.  This has implications – people in chronic stress situations should be encouraged to resolve them, as far as possible, and get stress-relieving therapy - mindfulness meditation, yoga, group therapy, or whatever works.