Stress state

People used to have bad nerves and nervous breakdowns, suffer from neurasthenia and neuroses or were just plain nervous - and it was something we preferred not to talk about. Today we call it stress, and people are talking and writing about it all the time.
Stress states are individual, and only you can know exactly what causes strain on you and what your stress states are: what your red environments are, and how you experience your red thoughts, emotions and bodily sensations.
But what follows is a general description of what stress is.
The red stress state is also called negative stress or distress (like dis-ease).
It is negative, uncomfortable, and unpleasant, and hence motivates us to find solutions to the problems that have arisen.
Stress refers both to the stress states we are in, and also to the stress factors: stressors, that trigger the stress state. Stress is triggered by and is inherent in the interaction we have with our environment.
A stressor is typically a situation or event we experience negatively, but can also be negative thoughts about a difficult situation, such as an exam we have to take in the near future.
In addition to psychosocial factors, there are also physical stressors.

A stress state is a state involving significantly negative cognition, emotion and body state.

Cognition

When we get out of balance, we can lose composure and control, and possibly break down or go berserk.
Once stress has been triggered, cognition is negatively affected. Concentration and attention is reduced, we have poorer memory, and a state of confusion can arise.
Stress thoughts are normally negative, automatic thoughts that arise without us being aware of them. They consist of emotional evaluations and interpretations. They usually run through our heads very quickly. They are subjective, general and categorical. Continuing negative thoughts can maintain our stress.

We all have different thought patterns that can make us vulnerable and reduce our stress threshold.
You might try to notice your own, and see if you think you understand them and can do something about them.
Below are some typical characteristics.
If we are sensitive about how other people treat us and what they think about us, we readily believe that we are being misunderstood, disregarded, overlooked, offended, cheated, derogated or that we are generally not given enough consideration, and have trouble coping with these things.
We can also have some negative basic precepts, for example, that you must, should or should not be a certain way. This can cause a lack of self-confidence, a reduced stress threshold, and lead to us not being able to assert ourselves and say "yes" or "no", when necessary.
An example of a negative set of thoughts about yourself might be: I am not good enough, I must not make mistakes, I will never be able to do it, I have to be perfect and everyone has to like me.
Worries and concerns are also typical for the stress state.

Emotion

Stress emotions are intense negative emotions. Every negative feeling of a certain intensity can arise in a stress state and prompt a particular reaction and action. A particular line of thought is linked to every feeling. You could try to make a list of your stress feelings and the thoughts and situations they belong to. You can do that here: recording negative feelings.
Negative emotions, and the three basic stress emotions in particular (anxiety, aggression and frustration) are described in the section on emotion. The acute emotions are very uncomfortable, but normally pass quickly and do not lead to any physical health problems.
Anxiety can feel like an insecurity, nervousness, or unrest, but can rise in intensity to panic, which feels like you are about to faint or go mad. Strong anxiety leads one to avoid or flee from certain situations.
In addition to real situations, for example if you are about to get hit by a car, anxiety also exists in many irrational forms, from fear of spiders to fear of people (social phobia). Compulsive thoughts and actions are also common in anxiety states.
Aggressive emotions vary from a light anger which quickly passes, to rage, or long-term states of bitterness and hate. Aggression is a behaviour that covers a very broad range: from drive and normal assertiveness to dominance, competitiveness, defensive aggression, revenge, punishment, bullying, violence, and sexual and pathological aggression. In addition to guilt, shame and regret where the aggression is directed towards ourselves.
Acute anger, for example in relation to a conflict which quickly passes, has no impact on health, but long-term, pent-up anger and habitual hostility is harmful to health.
It is common behaviour to suppress aggression. Social adaptation and pressure from others can be too strong and too inhibiting, for example, in a competitive work situation. Pent-up aggression can weaken your health and lead to chronic muscle tension and headaches.
Hostility as a personality trait together with a strong competition mentality and excessive ambition in work contexts leads to time pressure and stressed behaviour. These characteristics are called type A behaviour, which maintains a long-term, even chronic, stress state that increases the risk of cardiovascular disease. Measure your hostility level here: The Hostility Questionnaire.
Frustration/despair is the third basic stress emotion. A frustration reaction, capitulation, defeat reaction, type D behaviour, is triggered when a situation is perceived as overwhelming and hopeless, and is accompanied by emotions like despair, powerlessness, desperation, and grief.
Lifestyle stress is due to the fact that we are daily exposed to a number of negative influences, including a quantitative over stimulation/overload, i.e. too many negative influences and too much we have to overcome compared to our resources. We use energy and do not get a chance to recharge. It is also often accompanied by a qualitative under stimulation: what we are doing is boring, arduous, and something we do not feel like doing. These factors produce a frustration state, which if it continues day after day can develop into a fatigue depression, also called burnout.
Measure yourself for burnout here: Burnout Self-Test.
Quantitative and qualitative under stimulation, for example during unemployment, can also lead to a frustration reaction.

Body state

During stress, the body responds with an alarm reaction, in which hormones, the autonomic nervous system and immune defences are stimulated. The intention is for the body to be mobilised for fight or flight. Long-term stress weakens the body and can, in combination with other factors, lead to illness.
The physical symptoms experienced can include: tension, unrest, sleeping difficulties, palpitations, chest pains, headache, quavering voice, flush, dry mouth, hot flushes and sweating, shivering, dizziness, hyperventilation (shortness of breath), choking sensation, stomach/bowel symptoms (nausea, pain, diarrhoea), reduced energy and tiredness, loss of appetite and reduced sexual desire.
You can test yourself for stress: check your stress level.
And here you can read more about Life conditions and stress.