Measuring the Wear and Tear of Stress

I am interested in how stressful experiences impact the health of people. My book, Stress, Health, and Behavior, presents a review of the damaging effects of stress on physical and mental health. In this post, I will suggest a way that large health systems like hospitals, academic medical centers, and health maintenance organizations (HMOs) could develop a personalized stress risk score that would become a part of a patient’s electronic health record and inform him or her of how stress is adversely affecting overall health.

In the middle part of the twentieth century, continuing studies in stress and health were established by Hans Selye, a prolific physician-scientist based in Montreal. However, Selye, who defined stress as “the response of the body to any demand placed upon it,” did much of his research in laboratory animals and did not translate those findings into useful metrics for patients. In fact, his imprecise definition of stress was a big part of the problem.

A team of researchers, led by the late Bruce McEwen, tackled the complex question of how people age well, and through their work, they developed a new approach to thinking about stress, health, and aging. They introduced a new measure of stress called allostatic load to capture the progressive wear and tear that stress exerts on our bodies. They reasoned that recurring exposure to stressful stimuli that vary in frequency, duration, and intensity could render individuals susceptible to a variety of chronic diseases and mental disorders. Allostatic load reflects the extent to which internal physiological systems must adjust to new set points that may lie outside of the range of normal variations for each measure.

How does one measure allostatic load, and would it be useful as a personalized stress index? McEwen and his colleagues initially employed 10 variables, some of which are measured whenever you go to your primary care provider (PCP) for an annual physical examination (blood pressure, waist-to-hip ratio, serum high-density lipoprotein and total cholesterol, and hemoglobin A1C). Other measures included several hormones found in blood. From their results, they calculated an allostatic load score that increased as individual measures were elevated relative to the total group of participants in the study. Over the past two decades, additional clinical measures have been added by other researchers; the results have remained consistent. Higher allostatic load scores are associated with poorer health outcomes.

Consider the following results from several published studies:

• Higher allostatic load scores in healthy men and women who were 70-79 years of age were associated with lower levels of cognitive and physical functioning and increased risk of cardiovascular disease 2.5 years later and increased risk of death 7.5 years later.
• Data from the Scottish Health Survey indicated that higher allostatic load scores were associated with an increased risk of death from all causes 10 years later.
• African-American men and women have higher allostatic load scores compared with White men and women at all ages and these differences between races increase with age. Higher allostatic load scores in African-Americans may reflect levels of racial discrimination and could explain in part the poorer health outcomes and higher mortality rates of African-Americans compared with Whites, even after controlling for income levels.
• Some early results point to a beneficial effect on health measures of psychological interventions designed to reduce allostatic load scores.

At present, few healthcare providers talk to their patients about their stress levels. This is in spite of the fact that stress levels play an important role in health outcomes over the life course. Given the convincing results relating allostatic load scores to health outcomes, where do we go from here? I suggest that a behavioral measure of stress should be added as a component of the allostatic load score. A quick and easy measure is the 14-item Perceived Stress Scale, PSS, which takes just a few minutes to complete and could be folded into the allostatic load scores. It measures one’s perceived levels of stress over the past month. How we perceive and cope with stressors is as important as our actual frequency of stress exposures. The PSS could be completed on a tablet while you are in the waiting room of your PCP’s office. This combined measure could then be presented as a stress risk score (SRS) that is simpler to grasp than an allostatic load score.

Following an annual checkup, each individual would receive information through the health system app on where his or her SRS falls within an age-matched group of patients within the larger healthcare system. Third, if one’s SRS is clearly elevated, feedback would be provided through the electronic health system app suggesting local therapists, online resources, and wearable devices that might be helpful in managing stress levels and improving coping skills. A patient’s SRS score could also be discussed at each subsequent office visit by the PCP. Having excellent health in your 50s and beyond begins with a lower SRS in your 20s and 30s.

Conversations about stress levels should occur regularly between healthcare providers and their patients. Introducing the SRS into primary care settings is one way to shine a bright light on stress levels and their adverse effects on our health.