"Some stress is better than no stress"
Mental stress is not just harmful. It can also be inspiring. But where exactly is the border between too much and too little stress? "Psychological and physical health is a good indicator of the right degree of stress", says Professor Arno Villringer, Director at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS). In this interview he explains how stress influences our behaviour, why it’s unhealthy to have no stress, and what we still do not know about this apparently daily experience.
Professor Villringer, stress in general is not just bad but also necessary. How do we determine just the right amount?
Yes, stress of a certain amount and type is good. If it’s evoked by healthy and satisfying challenges – amazing! From experiments with mice it’s known that animals in a challenging environment develop more synapses than those in an impoverished environment. Having no stress is just as unhealthy as having too much. A lack of challenge can lead to lethargy and depression. In an extreme level this can be seen in people with Addison's disease, who are not able to produce the stress hormone cortisol. They’re always tired and unmotivated. It's probably impossible to accurately define an optimal level of stress. But one's health can be used as a proxy. If a person feels okay with their level of stress, emotionally and health-wise, then it's probably an acceptable level. The point being, we feel stress and if we pay close attention we should be able to feel when it's too much. Too much stress mostly arises when we feel we feel like we're not in control and only driven by external factors. This is mostly reflected in high blood pressure and heart rate, obesity, and depression. Too much stress can lead to chronic high blood pressure and heart rate, increased adipose tissue, and even depression. Furthermore, when under permanent pressure certain brain networks don’t function well, especially those involved in body perception and long-term goals.
We seem to know a lot about everyday stress. What still needs to be answered?
We do not know what makes individuals different. Why do some people get along very well while others struggle with the same stress load. Which physical and mental features make someone resistant to stress and what does that mean for the rest of their lives. There are lots of unknown aspects affecting stress reactivity such as genetic factors, early childhood experiences, abuse, or social factors. How can we use what we know to avoid being exposed to overwhelming stress all the time? When it rains do I think "gosh, what shit weather" or "oh well, at least it’s good for the plants". To be more relaxed in certain situations is not something that you can just tell a person to do. They have to learn to do that, similar to playing the piano. Our aim is to find the ideal way to handle stress for each person's demands. This is important as it also influences our decision-making.
In what way?
When chronically stressed we tend toward habitual behaviour where we don’t think much about long-term wellbeing, health, or beauty. When under pressure we invest all of our energy into handling "the enemy", meaning, in facing the challenge and keeping any other burdens separate. When we see snacks or junk food in these situations, for instance, we grab them without a thought for the consequences. In the long run this uncontrolled behaviour can lead to obesity, diabetes, or high blood pressure. These in turn can lead to atherosclerosis and eventually to stroke. Even the stroke itself is connected with massive stress and a real fear of death. It can even trigger posttraumatic stress-disorder, additional to the physical consequences.
What do we know about people that are more resistant to stress?
It’s mainly psychological factors that make people more resistant, such as the ability to transfer bad experiences into action, instead of just enduring them. On a physical level it’s crucial how well a person is able to return to their initial state after a sudden stressful situation. Meaning, how quickly he or she is able to lower their pulse and blood pressure. For that, high heart rate variability is a good condition. Previously, fluctuations in heart rate were seen as disconcerting. Today, we know that it helps you to calm down. People with posttraumatic stress disorder, for instance, don’t show high heart rate variability. In the long run it's better to experience strong stress symptoms acutely than to live under constant low-grade tension and never let it out. This could ultimately also be a sign for a depression. Physical and mental factors always influence each other. If I succeed in regulating my heart rate my mental strain sinks – and vice versa.
Does the brain differentiate between positive and negative stress?
It’s more crucial if we're exposed to acute or permanent stress than if it's positive or negative. To experience negative stress is not generally a bad thing unless it’s permanent. We know from work with apes that the young ones are better at dealing with stress if they’re separated from their parents from time to time, compared to those that never leave their parents. It seems that these experiences teach them how to deal with stress and how to handle challenging situations in the future.
Are we stuck with the properties of our stress systems or can we influence them?
At a certain level we can train them. Heart rate variability in particular can be enhanced with sport. Furthermore, there are several mental training methods by which you can learn how to handle hard situations. This includes emotion regulation techniques such as the reappraisal-method that is used to re-evaluate situations. My boss’ irritability probably has nothing to do with me but rather with his sick mother. Or, there is the method of brushing away strains, meaning the deliberate decision to not worry about a certain situation as it’s occurring.