Questioning the Expert
It doesn’t take a scientist — rocket or not — to predict that when you’re stressed, you’re probably going to look and feel pretty haggard. But leave it to a female scientist to wonder if those external signs of stress also signaled some cellular changes. Last December, Elissa Epel, PhD, a research psychologist at the University of California, San Francisco, published the first study to document the link between psychological stress and cell aging. Here, in this Personal Consult, she talks about her groundbreaking findings — and how they apply to us all.
Q. So just how does stress cause aging?
A. "We’ve known for 50 years that stress contributes to hypertension, cardiovascular disease, insulin resistance, and autoimmune disorders — diseases that can shorten our lifespan. But we had no direct documentation of how stress impacts aging at the cellular level. My team identified marked changes in the DNA of the white-blood cells in stressed-out women. Under prolonged emotional stress, the telomeres — branches at the tips of each chromosome, which allow cell replication — appeared shorter. When telomeres get too short, cells can’t divide and die sooner. Based on telomere length, we estimated that cells in the women studied had aged 9-17 additional years. It’s possible that as more cells die, the visible effects of aging — wrinkles, diminished eyesight — become apparent."
Q. Your subjects were female caregivers of chronically ill children. Why did you choose them to study?
A. "Caregiving is a prototypical example of something that creates chronic stress. Full-time caregivers have little time for themselves and make huge personal sacrifices, often at a cost to their own health. It is also something that happens to people randomly. Studying caregivers gave us an opportunity to examine the range of responses to an objectively similar situation, without having to factor in individual personality differences. We chose mothers of young children because we wanted to examine what stress would do to basically healthy people. With a sick child, mothers tend to take on most of the caregiving burden, and become depressed more often than fathers. While all parenting is undeniably stressful, having a child with a chronic illness is stressful at so many more levels. You might feel forced to give up your career — or simply decide that being a caregiver is more important than your career or work. But you may also mourn the loss of your normal life, the life you expected to have.
"By studying people with a similar external stressor, we were able to look at the importance of perceived stress, or the mental filter. So if you’re dealing with something difficult, how you think about it may be equally or more important than the actual situation. We found that those with higher perceived stress had greater cell aging."
Q. These women were obviously highly stressed. But how do their stress levels compare to those of an average woman’s?
A. "Our study also had a control group. While these women had no big stressor in their life that we knew about, they still had stress comparable to the normal experience of women who are juggling work and family.
"Although the real action between telomere shortening and cell aging was apparent at the highest levels of stress, we found the same relationship between perceived stress and telomere shortening in the control group as in the caregiver population. That means that stress and cell aging exist across the full range of stress levels. No one is immune."
More Q & A
Q. If the perceived level of stress is important, does that mean women who are in denial about their stress can avoid accelerated cell aging?
A. "No. Simply having or perceiving lower levels of stress did not make you immune to stress. The women in our study who had been caregiving for the longest had the shortest telomeres and the lowest telomerase, a substance that directly protects the telomeres. But that tells us that both objective stress, as well as subjective or perceived stress, are important contributors to cell aging."