What Is Stress?

What Is Stress?

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A lot of research has been conducted into stress over the last hundred years. Some of the theories behind it are now settled and accepted; others are still being researched and debated.

During this time, there seems to have been something approaching open warfare between competing theories and definitions: views have been passionately held and aggressively defended.

What complicates this is that intuitively we all feel that we know what stress is, as it is something we have all experienced. A definition should, therefore, be obvious... except that it is not.

Definition of Stress

Hans Selye was one of the founding fathers of stress research. His view in his book "The Stress of Life" was that "stress is not necessarily something bad – it all depends on how you take it. The stress of exhilarating, creative successful work is beneficial, while that of failure, humiliation or infection is detrimental." Selye believed that the biochemical effects of stress would be experienced irrespective of whether the situation was positive or negative.

Since then, a great deal of further research has been conducted, and ideas have moved on. Stress is now viewed as a "bad thing", with a range of harmful biochemical and long-term effects. These effects have rarely been observed in positive situations.

The most commonly accepted definition of stress (mainly attributed to Richard S. Lazarus in his book "Psychological Stress and the Coping Process") is that stress is a condition or feeling experienced when a person perceives that "demands exceed the personal and social resources the individual is able to mobilize." In short, it's what we feel when we think we've lost control of events.

This is the main definition used by this section of Mind Tools, although we also recognize that there is an intertwined instinctive stress response to unexpected events. The stress response inside us is, therefore, part instinct and part to do with the way we think.

How We Respond to Stress

Some of the early research on stress (conducted by Walter Cannon in 1932) established the existence of the well-known "fight-or-flight" response. His work showed that when an organism experiences a shock or perceives a threat, it quickly releases hormones that help it to survive.

In humans, as in other animals, these hormones help us to run faster and fight harder. They increase heart rate and blood pressure, delivering more oxygen and blood sugar to power important muscles. They increase sweating in an effort to cool these muscles, and help them stay efficient. They divert blood away from the skin to the core of our bodies, reducing blood loss if we are damaged. As well as this, these hormones focus our attention on the threat, to the exclusion of everything else. All of this significantly improves our ability to survive life-threatening events.

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Not only life-threatening events trigger this reaction: we experience it almost any time we come across something unexpected or something that frustrates our goals. When the threat is small, our response is small and we often do not notice it among the many other distractions of a stressful situation.

Unfortunately, this mobilization of the body for survival also has negative consequences. In this state, we are excitable, anxious, jumpy and irritable. This actually reduces our ability to work effectively with other people. With trembling and a pounding heart, we can find it difficult to execute precise, controlled skills. The intensity of our focus on survival interferes with our ability to make fine judgments by drawing information from many sources. We find ourselves more accident-prone and less able to make good decisions.

There are very few situations in modern working life where this response is useful. Most situations benefit from a calm, rational, controlled and socially sensitive approach.

In the short term, we need to keep this fight-or-flight response under control to be effective in our jobs. In the long term we need to keep it under control to avoid problems of poor health and burnout.


The ideas of "eustress" (good stress) and "distress" (bad stress) were developed by Hans Selye, one of the early researchers on stress. Selye believed that a mild level of stress encouraged animals and people to behave in a more active way, while an excessive level of stress would hamper their performance.

Since then, other people have drawn similar conclusions, substituting the idea of "stress" with the idea of "pressure". Framed in this way, this is an important and valuable idea. With all of its associations of unhappiness and loss of control, real stress is now seen as a bad thing in all circumstances.

The ideas of "eustress" and "distress" are therefore no longer useful. Indeed, they may be harmful in that they may encourage managers to try to motivate subordinates by increasing the amount of unpleasant stress they experience. The error in this approach is clear if you remember that "pressure" is a different thing from "stress".


Stress can cause severe health problems and, in extreme cases, death. While these stress management techniques have been shown to have a positive effect on reducing stress, they are for guidance only, and readers should take the advice of suitably qualified health professionals if they have any concerns over stress-related illnesses or if stress is causing significant or persistent unhappiness. Health professionals should also be consulted before any major change in diet or levels of exercise.

This site teaches you the skills you need for a happy and successful career; and this is just one of many tools and resources that you'll find here at Mind Tools. Subscribe to our free newsletter, or join the Mind Tools Club and really supercharge your career!

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Comments (52)
  • Over a month ago Sarah_H wrote
    As we all come to the subject of stress from our own unique perspectives, some people will find 'what is stress' a useful resource, starting point or reminder, whilst others have far more personal experience of stress, have developed knowledge and deeper understanding. There are currently 105 different resources on Stress in the club so there should be something for everyone. To find them you can go to Skill Areas on the left hand side of your home screen and then select 'stress management'. Hope this is helpful if you are looking for something more indepth.

    MindTools Team
  • Over a month ago airliz80 wrote
    This provides no helpful tools for managing stress
  • Over a month ago Michele wrote
    Hi gladysb,

    We have learned so much about stress and the stress response. It wasn't long ago that we discovered the link between stress and cortisol. We have a skill area devoted to stress management. Take a look:


    Mind Tools Team
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