The study suggests that most animals remain stressed longer than optimal after a stress-inducing incident.
Table showing the methodology between evolutionary modeling and empirical research. Trends in Ecology & Evolution.
Almost all organisms have fast-acting stress responses that help them respond to threats – but stress uses up energy, and chronic stress can be harmful.
A new study by an international team including researchers from the Universities of Bristol and Exeter suggests that most animals remain stressed longer than optimal after a stress-inducing incident.
The reasons for this aren’t clear, but one possibility is that there is a limit to how quickly the body can remove stress hormones from the circulation.
« While the physiological basis for the stress response system has been studied in depth, we have so far understood remarkably little about why this system has evolved, » said Dr. Sian English from the School of Biological Sciences at Bristol University.
“We have shown that considering both the mechanisms of hormone clearance and the characteristics of the environment – how predictable the threat is over time – can help explain the universal stress response and how it varies.
“Our results are all the more relevant today when we live in such uncertain times and stress is a topic of daily discussion. ”
Dr. English worked with experts in mathematical modeling including Bristol Professor, John McNamara, and Dr. Tim Fawcett of the University of Exeter to develop the conceptual framework and consider the broader effects on stress in fish, birds and mammals.
« We created one of the first mathematical models to understand how organisms evolved to deal with stressful events, » said Dr. Fawcett.
“It combines existing research on stress physiology in a variety of organisms with the analysis of optimal responses that balance the costs and benefits of stress.
“We know that the stress responses are very different between different species, and even between individuals of the same species – as we see in humans.
The researchers define stress as the process of an organism that reacts to stressors (threats and challenges in its environment), including its recognition and the stress response itself.
The model suggests that an animal living in a dangerous environment should have a high level of underlying stress, while an animal in a safer environment would benefit from it if it were able to increase and increase the stress quickly reduce.
« Our approach shows the predictability of the environment and physiological limits as key factors for the development of stress reactions, » said the lead author Professor Barbara Taborsky from the University of Bern.
« Further research is needed to advance scientific understanding of the evolution of this core physiological system. ”
The study was carried out by the Universities of Bern, Exeter, Bristol, Stockholm and Turku and the Brain Mind Institute of the École polytechnique fédérale de Lausanne.
« Towards an Evolutionary Theory of Stress Responses » by Taborsky, B. . , English, p. . , Fawcett, T. . W.. . et al. ;; in trends in ecology & evolution.
Scientists, research, physiology
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