Covid-19 taught most people that the line between tolerable and toxic stress – defined as persistent demands that lead to disease – varies widely. But some people will age faster and die younger from toxic stressors than others.

So how much stress is too much, and what can you do about it?

I’m a psychiatrist specialising in psychosomatic medicine, which is the study and treatment of people who have physical and mental illnesses. My research is focused on people who have psychological conditions and medical illnesses as well as those whose stress exacerbates their health issues.

I’ve spent my career studying mind-body questions and training physicians to treat mental illness in primary care settings. My forthcoming book is titled Toxic Stress: How Stress is Killing Us and What We Can Do About It.

A 2023 study of stress and aging over the life span – one of the first studies to confirm this piece of common wisdom – found that four measures of stress all speed up the pace of biological aging in midlife. It also found that persistent high stress ages people in a comparable way to the effects of smoking and low socioeconomic status, two well-established risk factors for accelerated aging.

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Good stress, bad stress

Good stress – a demand or challenge you readily cope with – is good for your health. In fact, the rhythm of these daily challenges, including feeding yourself, cleaning up messes, communicating with one another and carrying out your job, helps to regulate your stress response system and keep you fit.

Toxic stress, on the other hand, wears down your stress response system in ways that have lasting effects, as psychiatrist and trauma expert Bessel van der Kolk explains in his bestselling book The Body Keeps the Score.

The earliest effects of toxic stress are often persistent symptoms such as headache, fatigue or abdominal pain that interfere with overall functioning. After months of initial symptoms, a full-blown illness with a life of its own – such as migraine headaches, asthma, diabetes or ulcerative colitis – may surface.

When we are healthy, our stress response systems are like an orchestra of organs that miraculously tune themselves and play in unison without our conscious effort – a process called self-regulation. But when we are sick, some parts of this orchestra struggle to regulate themselves, which causes a cascade of stress-related dysregulation that contributes to other conditions.

For instance, in the case of diabetes, the hormonal system struggles to regulate sugar. With obesity, the metabolic system has a difficult time regulating energy intake and consumption. With depression, the central nervous system develops an imbalance in its circuits and neurotransmitters that makes it difficult to regulate mood, thoughts and behaviors.

Treating stress

Though stress neuroscience in recent years has given researchers like me new ways to measure and understand stress, you may have noticed that in your doctor’s office, the management of stress isn’t typically part of your treatment plan.

Most doctors don’t assess the contribution of stress to a patient’s common chronic diseases such as diabetes, heart disease and obesity, partly because stress is complicated to measure and partly because it is difficult to treat. In general, doctors don’t treat what they can’t measure.

Stress neuroscience and epidemiology have also taught researchers recently that the chances of developing serious mental and physical illnesses in midlife rise dramatically when people are exposed to trauma or adverse events, especially during vulnerable periods such as childhood.

Over the past 40 years in the US, the alarming rise in rates of diabetes, obesity, depression, PTSD, suicide and addictions points to one contributing factor that these different illnesses share: toxic stress.

Toxic stress increases the risk for the onset, progression, complications or early death from these illnesses.

Suffering from toxic stress

Because the definition of toxic stress varies from one person to another, it’s hard to know how many people struggle with it. One starting point is the fact that about 16% of adults report having been exposed to four or more adverse events in childhood. This is the threshold for higher risk for illnesses in adulthood.

Research dating back to before the Covid-19 pandemic also shows that about 19% of adults in the US have four or more chronic illnesses. If you have even one chronic illness, you can imagine how stressful four must be.

And about 12% of the US population lives in poverty, the epitome of a life in which demands exceed resources every day. For instance, if a person doesn’t know how they will get to work each day, or doesn’t have a way to fix a leaking water pipe or resolve a conflict with their partner, their stress response system can never rest. One or any combination of threats may keep them on high alert or shut them down in a way that prevents them from trying to cope at all.

Add to these overlapping groups all those who struggle with harassing relationships, homelessness, captivity, severe loneliness, living in high-crime neighborhoods or working in or around noise or air pollution. It seems conservative to estimate that about 20% of people in the US live with the effects of toxic stress.

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Managing stress

The first step to managing stress is to recognise it and talk to your primary care clinician about it. The clinician may do an assessment involving a self-reported measure of stress.

The next step is treatment. Research shows that it is possible to retrain a dysregulated stress response system. This approach, called “lifestyle medicine”, focuses on improving health outcomes through changing high-risk health behaviours and adopting daily habits that help the stress response system self-regulate.

Adopting these lifestyle changes is not quick or easy, but it works.

The National Diabetes Prevention Program, the Ornish “UnDo” heart disease program and the US Department of Veterans Affairs PTSD program, for example, all achieve a slowing or reversal of stress-related chronic conditions through weekly support groups and guided daily practice over six to nine months. These programs help teach people how to practice personal regimens of stress management, diet and exercise in ways that build and sustain their new habits.

There is now strong evidence that it is possible to treat toxic stress in ways that improve health outcomes for people with stress-related conditions. The next steps include finding ways to expand the recognition of toxic stress and, for those affected, to expand access to these new and effective approaches to treatment.

Lawson R Wulsin is Professor of Psychiatry and Family Medicine, University of Cincinnati.