Chronic stress without stressors?

After more than 70 years, stress science still does not fully understand how a chronic stress response develops. It has taught us a tremendous amount about short-term responses to stressors (threats). However, as we will see below, chronic responses occur precisely in situations where there are no current stressors, or too few to explain these responses. With its focus on immediate responses to stressors it has put us on the wrong track.

Tigers never made us sick

As a result, in almost every popular article, book, or TED-like talk about stress, the stress response is still spoken about as a troublesome relic from ancient times, when facing a tiger or enemy tribe etc. would trigger a fight or flight response: an anachronistic response to threats that are no longer there. At the same time, it is assumed that there are actually no serious threats in our modern world anymore, but that we still react as if there were. But if you ask where that tiger is now, or that enemy tribe, there is no real answer: an embarrassed mumble or a muddled vague reply at best. It is claimed that we now react to small harmless things instead. But it would be evolutionarily silly if our stress system did that. Think about it: in the absence of major dangers, we supposedly react just as vigorously to small ones? That would have no survival value at all. In reality, in ancestral times, encounters with predators and hostile humans were probably quite sporadic to start with.

Stressors are too rare to make us sick

Far more important than this is that in modern times stressful events are also relatively rare (at worst a few times a day) and fairly short-lived – far too infrequent and short-lived to be responsible for any meaningful part of our chronic stress response. It is however a chronic enhanced stress level that can make us sick and even die before our time. Stressors just don't seem to matter that much.

Long-lasting high stress response levels

What do we mean by chronic high stress responses or levels? Think of continuously high blood pressure or heart activity, high or too low levels of stress hormones, or an immune system that is chronically disrupted. Crucially, we are talking about continuously increased levels - even at night during sleep - that typically cannot be statistically explained by lifestyle factors such as smoking, alcohol and diet. Moreover, these increases are often not more than relatively moderate but … chronic, which in the long term can lead to illness and premature death. Size doesn’t matter, but duration does.

Situations with chronic stress responses but without stressors to explain them

Let's take a look at situations in which these elevated chronic stress levels occur – which makes them in fact by far the most important stress factors, if not the only ones, that increase the odds for bodily disease. These situations are, for example, loneliness, low socioeconomic status, being a member of a discriminated minority, marital stress, work stress, being an adult with a history of early life stress or prenatal stress, or a person with chronic anxiety or other long-term emotional problems. Stressful incidents are far too infrequent and brief in all these situations to explain the higher chronic stress levels. In chronic anxiety there is even by definition no real stressor. Thinking of stressors (e.g., worry) can explain some extra part of a chronic high stress level (as my colleagues and I have shown), but unlikely all of it. Even unconscious ‘stress representations’ (another speculative idea of us) are unlikely to explain a truly chronic response.

Disease and early death

Importantly, in all these situations there is not only an enhanced stress level but also proof of higher risk for disease and often also untimely death, which also remains after controlling for lifestyle factors. In other words, you will die earlier than others, on average, when you are lonely, poor, discriminated and so forth.

Mistaking the bathwater for the baby

So, there is abundant evidence of chronic stress levels in situations without stressors as causes. Still, the hypothesis underlying much of stress and health research is insistently focused on stressors. It is the so-called reactivity hypothesis, which holds multiple responses (high reactivity) to stressors responsible for causing disease. I hope to have made clear above that this is the wrong theory. It leads to missing the most important part: the chronic response. In fact, in many studies the chronic stress response (or level) is even actively removed. In typical stress experiments reactivity is taken as ‘response change from baseline’. But the baseline or ‘resting level’ is exactly where we should look for chronic responses! Taking the baseline as something to correct for when studying stress effects on health is mistaking the bathwater for the baby - and throwing away the baby! It is looking in the wrong place with the wrong theory.

Stop focussing on stressors

Thus, we should stop focussing on which stressors seem to trigger the response, and look for a better explanation of chronic stress levels in all these situations without stressors. Why do so many people have a chronic stress response? Current stress science does not offer a better explanation. Until recently. Looks like we've been wrong all along.

I explain this in my next blog, titled ‘Stress? It’s safety, silly!