Since the early years of the 20th century, a lot of research has been done into the industrial phenomenon that we now call stress. There exists a small library full of theories, methods, principles and explanations; some of these theories are now pretty well settled and accepted, others are still being researched, developed and debated.
Life would be much simpler if these theories were all complementary and compatible, but it's not and they're not. Even definitions of stress vary; both between researchers, and over time.
In 1956, Hans Selye's views were pretty much standard: "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 and humiliation is detrimental." Selye focused on the biochemical effects of stress, which would be experienced irrespective of whether the outcome was positive or negative: a stress-neutral chemical perspective.
Since then, stress has had a pretty bad press; it is now seen almost universally as a bad thing, with harmful biochemical, physiological and behavioural effects, which almost never offer positive outcomes.
Nowadays, stress is most commonly - though not universally - defined as a state experienced when a someone feels that 'demands exceed the personal and social resources the individual is able to mobilize.' This feeling or perception - thinking that we cannot cope and that we have lost control - underpins most modern thinking on stress.
That does not mean, however, that the early researchers were plain wrong. There are two aspects at work here: one a conscious perception, the other a primitive biochemical response to unexpected events.
On this website - and in most modern literature - the word 'stress' implies 'excessive levels of stress'. To read our definition of stress, click on 'What is Stress' below