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Even unconscious stress can cause stress symptoms

Our vision of stress is starting to change fundamentally. We can suffer stress without even being aware of it, while sleeping as wall as during the day. Professor of Psychology Jos Brosschot will discuss this phenomenon in his inaugural lecture on 2 December.

Stress is a worldwide epidemic

Brosschot's field of study is the psycho-physiological mechanisms of stress in daily life. It is a highly topical subject: according to the World Health Organisation stress has now become a worldwide epidemic. Work-related stress, for example, is the cause of more than half the working days lost and it carries a four-fold risk of vascular disease.  

Prof. Jos Brosschot

Research focused on stress response

Research on stress has for a long time focused on the so-called stress response, or the fight-or-flight reaction. The term refers to the reaction to a stressful event: at work that could be a bullying colleague, an intimidating boss or a performance interview; outside work it could be just missing a train or having an argument with your partner.  How long does it take before your blood pressure returns to normal, and is there anything you can do to influence it? 

Fight or flight: a healthy reaction

We have gradually come to appreciate that this type of fight-or-flight response is a healthy - sometimes life-saving - reaction that has a long evolutionary history. In principle, there's nothing wrong with this; we have to look elsewhere for what makes stress unhealthy. Unlike animals, humans all too often ruminate on stressful events: long before that difficult performance review we're already worrying about it and going over it again and again in our heads. We keep asking ourselves what could possibly happen. This rumination has physical consequences: our heart rate, blood pressure and cortisol levels are all raised. 

Umbrella term

Long-term stress responses can occur that are unrelated to immediate stress factors or events. Such long-term stress is probably bad for our health. Brosschot and his American colleagues Julian Thayer and Bill Gerin came up with the umbrella term perseverative cognition (persistent thinking). What the researchers mean by this term is specifically the continual rumination on negative events in the past or possible negative events in the future. They expected there might also be other forms - and they were right. 


Fight or flight, a basic human response

Thinking further about stress that is not due to any direct, visible cause led the researchers to the concept of perseverative cognition. One of their studies focused on daydreams, something that people spend about half their time doing.  They found that about 40% of these daydreams relate to positive events, 30% to negative events and 30% neutral events. And that that semi-aware thinking about negative and neutral events makes us less happy, along with the stronger and more unhealthy physical responses it gives rise to. This is also an example of perseverative cognition. 

Unconscious stress

Their own research led Brosschot and his colleagues to the insight that perserverative cognition can even continue while we are sleeping; after spending a  day ruminating, we can experience very strong stress symptoms. Indications that this can also happen in the daytime, when we are on alert, made the researchers curious about unconscious stress during the day. 

Always on the alert

Does there always have to be an actual threat, Brosschot and his colleagues wondered.  They looked at chronic stress situations where there is no perceivable threat. Their thinking led them to the experience of loneliness and how this can affect our feeling of security, our sense of being protected. They concluded that a lack of security could well give rise to a continuous stress response. The stress response remains permanently switched on, unless it is turned off, which can happen when the sufferer feels safe and protected, or suppressed. 

Questions to be answered

This is the theory that Brosschot, Godaert, Thayer and Verkuil will be exploring further. Their research touches on one of the basic human needs and may make a contribution to explaining why stress is such a global problem. There are more questions to be answered: Do present-day humans suffer the same stress response as when our ancestors experienced a flight-or-fight response as a result of a feeling of insecurity in an earlier stage of human development? And can this response combat all forms of vulnerability, such as growing older or being obese? Brosschot will be trying to find answers to these fascinating questions. 

Inaugural lecture by Jos Brosschot 2 December


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