Wear and Tear of Stress: The Psychoneurobiology of Aging
Age may be more related to reactions to stress and the absence of disease rather than to a person's chronological age, say leading researchers in the fields of neurobiology and psychoneuroendocrinology. And healthy aging is a good bet if stress can be moderated along with adopting an active, healthy lifestyle. This finding will be presented at the 114th Annual Convention of the American Psychological Association (APA).
From a review of studies on how stress hormones affect the brain, psychologist Bruce McEwen, PhD, of the Laboratory of Neuroendocrinology at The Rockefeller University, finds more evidence that biological and behavioral stress responses can be adaptive in the aftermath of stress, but can also cause damage when they are over- or under-produced and go on for a long time. "Acute stress seems to enhance immune function and improves memory but chronic stress has the opposite effect and can lead to disorders like depression, diabetes and cognitive impairment in aging," said Dr. McEwen.
Cumulative stress effects, said McEwen, are showing up in people who are under constant stress, like those in caregiver situations or those who suffer from obesity and/or diabetes. These people are more likely to have decreased telomerase activity. Telomeres are enzymes that regulate how many times an individual cell can divide. Telomeric sequences shorten each time the DNA replicates, which is a process that happens prior to cells dividing. When at least some of the telomeres reach a critically short length, the cell stops dividing and ages (senesces) which may cause or contribute to some age-related diseases.
There is also more evidence that the brain is more involved in a person's stress response than previously thought, said McEwen. The brain interprets what is threatening, i.e., what is stressful (whether it be public speaking or perceptions of social status) and then regulates the behavioral and physiological responses through the autonomic, immune and neuroendocrine systems. If the brain is under too much stress for too long, said McEwen, "we can see structural and functional remodeling changes that affect how it functions."
"These brain changes, which appear to be reversible, are able to change by not only pharmaceutical agents but also by lifestyle changes like exercise, diet and social support," said McEwen.
In another review of the current literature on the interactions of the brain, stress and the endocrine system, more evidence shows how cumulative stress and the occurrence of disease may define age more than chronological aging. According to the review, certain diseases start to occur when the anabolic hormone levels start to decrease