Selye and Levi have defined stress as a non-specific conventional and phylogenetic basic response pattern, the primary function of which is to prepare the body for the physical activity such as resistance or flight.

There are two kinds of stresses that are distinguished by Selye and Levi. Eustress is synonymous with healthy essential stress, produced for example, like joy, and kind of positive impulses, sensible recreational activities, sports practiced as a hobby, etc., Distress is synonymous with morphigenous stress that has to be controlled. For example, continuous mental or physical strains of any kind, anger, frustration, state of tension seemingly without hope. There is nothing unique that happens at psychological level, that is called stress reaction. The changes that occur are triggered at the highest level of the brain and travels down the body through imbalances at:

i. Autonomic nervous system
ii. Endocrine system

Stress, according to yoga is imbalance, imbalance is misery. At the mental and physical it is excessive speed and thus a demanding situation, it causes pain and leads to ailments and diseases.

Repeated thinking leads to attachment, attachment to desires, desires (greed, lust,fear, possessiveness, etc.,) to anger, anger to infatuation, lack of awareness, the power to discriminate and ultimately one gets lost.

Egocentric personalities are characterized by strong obsessions,ambitions, likes and dislikes. Emotional imbalances emerge out of them and upsurges often. Else if they get suppressed, they percolate to the physical level resulting in heart attacks or nerve shattering diseases. When emotional outbursts like anger continues, they are infatuated, obsessed, loose all discrimination powers and start to act from instinctive level. This, Pathanjali, called as "Adhinivesha",a state of helplessness, constriction, slavery or bondage that is the grossest manifestation of stress.

Stress hazards decrease the quality of life and could lead to many ailments. Four distinct stages are recognized:

1. Psychic phase
2. Psychosomatic phase
3. Somatic phase and
4. Organic phase

Modern medical system offers many drugs to effectively reduce the sufferings at the somatic and organic phases.Yoga tackles the problems at Phases 1 & 2 itself.

Apart from periodically and regularly releasing the accumulated stress and tensions, which is essential to begin with, it is imperative to move towards a stress free life.This helps us in retaining our sharp intellect and all the powers and capabilities obtained by a sensitive mind which becomes vital for day to day functioning in this hi-tech era. The regular release of stress helps us to spread this insight through the action phase. Application of karma yoga techniques helps us to reduce the accumulation of tension and stress and thus makes possible tension free life a reality. Thus yoga with physical and mental and emotional personality and a holistic understanding offers a total approach to the challenge of stress.