Stress can be understood in terms of the following models:

Tiredness/mental fatigue

Stress can be understood at the simplest level as our minds not having enough time to recuperate or heal following a period of activity. Just as after a very busy day we want to chill out and do nothing physically, we need similar breaks for our minds as well. Unfortunately our minds never rest. Even during periods of rest and sleep the mind is constantly thinking and planning. The only time when our mind rests fully is when it is awake and is in an emotionally neutral state – neither too happy nor too sad. Unfortunately we are always seeking some or the other activity/situation to feel happy thereby giving little time for the mind to heal itself.

Unfulfilled potential

Not being able to do what one is capable of or supposed to do can result in stress. This is the opposite of the tiredness model and relates to not doing something rather than doing things. Each individual is unique and it would be reasonable to assume that nature has given each one of us a unique potential to carry out certain tasks in this world. Due to our unique individuality and the situation in this world there are certain things that only we can do. Not doing what we are supposed to do will result in guilt and depression. However it may be a difficult task to know one’s true calling, the purpose why we are here.

Desire

Desires are the spice of life, without them we wouldn’t want to live. This makes us invent new desires when the old ones are fulfilled. In fact a desire free state would be the most relaxed state to be in. We do not feel okay when nothing much is happening in our lives. As a result our minds are never free from thinking, planning, seeking, creating new emotions and excitement etc. These apparently positive endeavours also result in stress, which we can describe as a positive stress. If the desires that we carry in our minds are not fulfilled it causes enormous stress, especially if we cannot forgo them or work towards alternative goals in life. If the desires are fulfilled it creates further stress as each desire attained sows seeds for further desires.

Relationship model

Relationships can cause stress in two totally opposite ways i.e. as a result of not feeling connected or feeling isolated and as a result of being in an enmeshed relationship.

Existential model

Existentialism is a branch of philosophy that believes that stress is an integral part of life and can not be avoided. It goes a step further in saying that the real stress of being a human being is much greater than we normally appreciate.
It is not difficult to understand that apparently life seems unfair. It is difficult to comprehend why people are struck with tragedies, sickness, and financial ruin for no fault of their own. Very carefully planned lives are shattered by the cruel hand of destiny. A good life is guaranteed to no one and in spite of our best efforts, we remain subject to chance and uncertainties. How can we feel secure in this world? We probably live in denial for most of our lives and organise our lives in such a way that we do not confront this existential stress that is linked with our mortality, meaning of life, sense of responsibility, freedom of choice and ultimate fate. According to existentialism a constant awareness of this type of stress is desirable as it makes us more human and our lives richer. Inability to acknowledge and accept this stress can result in clinical anxiety.

Strong negative emotions

This model is very close to the desire model as unfulfilled desires lead to negative emotions. It is not the intensity of the negative emotions that is linked to stress but our inability to digest or process these negative emotions. This is closely linked to our value system, world view, cultural beliefs, core identities and life goals. These factors dictate what would/would not be acceptable to us.

Control model

Wanting to be in control of our own and others lives all the time can result in high levels of stress. We do not have full control over the results of our actions as a lot of outside factors come into play in deciding the outcome. We can only control our actions. It is therefore important to make a distinction between our actions and the results, and change our focus from being result-oriented to action-oriented. Surrendering the issue of results to higher forces can be helpful in this regard.

Physiological model

Our nervous system is composed of two different subsystems: the central nervous system and the autonomic nervous system. The autonomic nervous system has been divided into two further groups: the sympathetic nervous system and the parasympathetic nervous system.

We experience stress at the body level in the form of sympathetic nervous system over-activity or an imbalance between the sympathetic and parasympathetic nervous system activation.

Normally both these systems work in harmony, very much like the accelerator and the brakes in our car. But in stress situations there is an imbalance between the two. It is possible to correct this imbalance by means of biofeedback treatment and certain mind-body therapies.

Spiritual/religious model

In everyday life we tend to identify ourselves with the apparent systems that are finite i.e. our body, mind, possessions, environment and people but at a deeper level our existence is linked with and supported by the infinite cosmic forces that support our life on this planet. Finding a meaningful connection with the infinite is considered very important for our well being in most spiritual traditions. Losing this connection can make us vulnerable to stress that can result from the vicissitudes of life.

Genetic/biological model

For some individuals genetic and biological factors play a major role compared to the environmental ones in producing stress. These factors modulate release of certain chemicals such as serotonin and adrenaline which are involved in producing anxiety and depression.

AUTONOMIC NERVOUS SYSTEM AND STRESS
Our nervous system consists of two separate parts, one that is under our control called the central nervous system which controls functions such as hand movements, and the other that is not under our control is called the autonomic nervous system which is responsible for regulating the functions such as gut movements, heart beats, blood flow in our arteries, respiratory rhythms, skin temperatures, brain waves etc. Until recently it was believed that apart from very few functions such as respiration, muscle tension etc we can not control these functions but with the advent of biofeedback treatments it has become possible for us to control these functions as well. This research has had important implications in stress management as the stress that we experience inside our bodies results from alterations in the autonomic functions

The autonomic nervous system can be broadly divided into the following two subsystems:

1.Sympathetic nervous system: that is involved in dealing with emergencies such as fear, fight and flight. It puts our system in hyper drive by accelerating the heart rate, blood flow in to muscles and our respiratory rate. The enables us to deal with any emergency.

2.Parasympathetic nervous system: which plays the important functions of healing, regeneration and nurturance in times of peace. It slows down the heart and respiration rates and increase movements of intestines. It also results in increased blood flow to skin thereby increasing skin temperature.

It is important for normal functioning of our psyche that these two systems function in harmony with each other. Any imbalance in the two systems can result in illness. An increase in sympathetic activity can result in anxiety/panic attacks, hypertension, irritable bowl disease, premature ejaculation etc and a hyperactivity of parasympathetic activity can result in illnesses such as bronchial asthma, syncope, chronic fatigue syndrome.

Summary of the causative factors

So far we have discussed stress mainly in terms of a mental reaction to something and this mental reaction is a consequence of how we perceive and judge different things in this world. One can ask, why in the first place, one person reacts in a certain way and not in other ways? Apart from genetic predisposition, we can understand this in terms of early childhood experiences. According to psychoanalysis, the software of our minds are written in the first five years of our lives and during the rest of our lives we keep re-playing that software. However, more recent theorists believe that we can change that software by will later on.