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We all know the feeling of growing old before our time, for a while. Some days the kids can make a young mother feel like Grandma. Some bosses and some jobs drive us into early retirement at 55 or 60. Then we feel young again and find a second career. Every president goes grey or greyer in the Oval Office. Without term limits, the better ones would die in that office.
The last time I wrote a blog about biological aging (April 2022, “How Old Are You?”), the question was, how can we know how old we are biologically, compared to chronologically? The piece ended with a few more questions to ponder, one of which was, what kinds of stress accelerate aging?
This question is only worth pondering if you believe that some kinds of stress are good, some are tolerable, and some are toxic to our health. Forget the dream of a stress-free life. None of us really wants that. Good stress is the bread of life: meeting the needs of our loved ones, playing games, satisfying appetites. And tolerable stressors are the demands we have the resources for: jobs we can do, bills we can pay, problems we can manage.
What we want is to avoid the toxic stressors that threaten us, slow us down, and eventually make us old before our time. Demands that exceed our resources over and over: bills we can’t pay, family we can’t take care of, crimes we can’t protect ourselves from, relationships that threaten us, pollution or weather we can’t escape, diseases we don’t manage well enough.
Making these distinctions between good, tolerable, and toxic stress can be tricky, even for the experts, since measuring stress is a complicated task, and people vary a lot in how they experience stress. The time it takes for toxic stress to trigger a stress-related illness can be many years. It’s useful to think of your toxic stress as the process that begins with your perception of persistent demands that exceed your resources.
The potentially simpler question—what kinds of stress accelerate aging—assumes that accelerated aging leads to poor health and early death. It also assumes that different kinds of toxic stress might have small or large effects on aging and might also affect the aging process by very different pathways. There is good evidence to support both of these assumptions. So, if we want to try to slow down our own biological aging process, we might need to use different approaches for different kinds of toxic stress, if the kind of stress matters. Take a break from the kids, switch jobs, worry less, or play more? How can we know what to try next?
In June of this year the first study to address this question about the kinds of stress that affect biological aging was published by a team from Otago, New Zealand; Durham, North Carolina; and London, England. Taking advantage of the Dunedin Study that began half a century ago by enrolling over a thousand children at birth in Otago, New Zealand, this team has collected at regular intervals over the years a rare combination of four measures of stress and 19 biological markers for their Pace of Aging measure. The aim of the recently published study was to compare these four measures of stress to two other known factors that accelerate aging, smoking and low education levels, for their effects on biological aging up to the age of 45. Among studies of the big mind-body questions, the methods of this study are as rigorous as it gets.
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They found that all four kinds of stress (perceived current stress levels, adverse childhood experiences, cumulative stressful life events, and a diagnosis of PTSD) were associated with accelerated aging, shortening life by a range of 1-2.4 months per year, an effect comparable to the effects of smoking and low education. The strongest effect on aging was for perceived stress, the person’s rating of the severity of their current levels of distress. This surprising finding raises the suggestion that our perceptions of high stress could be more toxic for aging than the number of stressful events we experienced or when we experienced them.
This is just one well-designed study, but it leaves us with a few pearls. It suggests that by mid-life the people with higher stress levels of all kinds were aging approximately two months faster per year than people with lower levels of stress. The study suggests that multiple measures of stress teach us more than any single measure can. Some kinds of stress accelerate aging more than others. And our perceptions of high stress may consume more biological resources than we’re aware of. If we think we’re highly stressed, we’re probably wearing down our stress response systems. Worry may age us faster than life events do.
This study also raises a question for those of us who think of our lives as highly stressful: could learning to cope better and worry less about stress not only lighten our daily burdens, but also slow down the pace of our aging by a month or two a year? We will have aged a lot, chronologically, before we get to see a study that answers that question.