CONCEPT OF VYADHIKSHAMATVA IN AYRVEDA

For prevention of diseases, Ayurveda had advocated the adherence to concepts like dina charya, ritu charya, sadvritta , Na vega dharan  etc.  these measures are useful in preventing the lifestyle related diseases but for preventing the Aupsargik rogas (communicable diseases), Janapada dhwansa rogas (epidemic diseases), Krumij Roga (Infectious diseases), Asatmyaj roga (allergic disorders), the concept of Vyadhikshamtva (Immunity) is propagated by the Ayurvedic science [1]. According to the concept of Ojas or Vyadhikshamatva or Bala (immunity), the body‟s resistance is of tremendous importance in the daily welfare of living beings not only for disease prevention but also for rapid recovery after disease affliction. [2] Ayurveda propounds that prevention is an equally important aspect of disease management as cure and thus, strengthening the immune system, is a natural way to help the body fight against the disease-causing pathogens. Acharyas promoted the use of Rasayana (Rejuvenation) to enhance ojas and vyadhikshamatva (immunity). 
This article is an effort to present Ayurvedic concepts of Vyadhishamatva.


INTRODUCTION
The healthy and joyful long life is the main priority of Ayurveda. Ayurveda explained the concepts related to health and diseases in details, also the knowledge of etiology, symptomology, therapeutics, numerous methods to sustain healthy status and causes behind falling sick. [3] The main purpose and objectives of Ayurveda is the preservation of health in healthy individual and eradication of diseases which are curable.
The concept of Vyadhiksamatva (immunity) is of tremendous importance in the daily wellness of human beings; for prevention and recovery from diseases. When etiological factors come in contact with the body they try to produce disease. At the same time the body tries to resist the disease. This power of the body, which prevents the development of diseases or resists a developed disease, is called Immunity. Vyadhikshamatva in Ayurveda is not merely immunity against a specific infectious agent or disease such as typhoid, measles or rubella for which modern medicine provides "immunizations". Rather, Vyadhikshamatva implies a resistance against the loss of the integrity, proportion, and interrelationship amongst the individual's doshas (bioenergies) and dhatus (tissues). Resistance to disease or immunity against disease is of two kinds i.e. the one which attenuate the manifested diseases and other variety prevents the manifestation of diseases Various factors which contribute towards vyadhikshamatva are normal doshas, equilibrium state of dhatus normal agni, patency of srotas etc. During certain conditions or due to certain factors even unwholesome (ahitakara) dietary practices do not produce disease immediately. All unwholesome (ahitekar) food articles are not equally harmful, all doshas are not equally powerful; all persons are not equally capable of resisting diseases [4] Vyadhikshamatva helps in to achieve the aim of Ayurveda i.e. स्वास्थस्य स्वास्थ्य र�णम ्। आतु रस्य �वकार प्रशमनम ् च।। [5] Ayurvedic literature from ancient texts to usnderstand role of Vyadhikshamatva as per Ayurveda concept which may be helpful in this battle for survival of human beings.

MATERIAL AND METHOD
The materials were collected from the classical Ayurvedic literatures, magazines and research journals.

NIRUKTI
• It is made of two words i.e. vyadhi and kshamatva.

सहजं वत ् शर�रसत्वयोः।
The constitutional strength present since birth It depends on the healthiness of shukra (sperms) and artava (ovum). According to Ayurvedic concept of Genetics, if two parents" genetic makeup is healthy, then children are similar healthy If parents is susceptible to certain diseases, those diseases may be carried over into the next generation [13] This concept indicates congenital abnormalities which occur due to abnormal changes at genes or chromosomal levels.

कालक ृ तं ऋतु �वभागजं वयक ृ तं च।
Temporal strength is the one which is based on division of seasons and age of the person. In Adana kala (late winter, spring and summers) Bala of individual will be less and in Visarga kala (rainy seasons, autumn and winter) it will be more. Bala will be Alpa (minimum) in child and old age, Uttama (maximum) in young age.

यु िक्तक ृ तं पु नस्तद्याहारचे ष्टा योगजं ।
Acquired strength is the one which is achieved by the combination of diet and physical activities.

OJAS
The essence of saptadhatus is called Oja and it is the seat for strength, hence called bala situated in the heart It is viscous, unctuous, greasy, Somatmaka (preponderant in watery principal), clear (transparent) and slight reddish yellow in color. its loss (destruction, absence) may lead to death and its presence in the body (and life) sure to survive. 13

Classification of OAJAS
According to chakrapani Oajas is of two types [14] Para Oajas: Para Oajas is prime Oajas, where Prana the life resides. It is 8 drops in quantity, present in heart, even a part of destruction of Para Oajas leads to death. It is white and Yellowish red in colour.
Apara Oajas: Apara Oajas is half Anjali in quantity,it is less important compared to Para oajas

Ojakshaya (decrease or loss of Ojas)
Ojas undergoes decrease by anger, hunger, worry, grief and exertion. With such decrease, the person becomes fretful, debilitated, worries much again, feels discomfort in the sense organ, develop bad complexion, bad mention and dryness of skin. [15] According to Sushruta there are three stages of abnormal ity of Oajas are [16] Oajovisransa: symptoms of Oajovisransa are looseness of joints, body ache, and displacement of Doshas from their seat, tiredness and impairement in performance of action.
Oajovyapada: symptoms of Oajovyapada are heaviness in the body, stiffness in joints, depression, discolouration, body ache, drowsiness, excess sleep and non-pitting ede-ma.
Vyadhikshamatva and give brief explaination in two divisions.
1) Vyadhi-balavirodhitvam: It is the capacity to put away or resist the power (severity) of the diseases i.e. power to resist the development of disease. 2) Vyadhi-utpadakapratibandhakatva: The counterattacking strength of the body to inhibit the occurrence and re-occurrence of the disease.

FACTORS AFFECTING VYADHIKSHAMATVA
There are around nine types of factors accountable for reducing the immunity. -Ashtaninditiya Purush.

CONCLUSION
The concept of Vyadhikshmatva is very well documented in Ayurvedic literature.Vyadhikshamatva which is synonyms to swastha, bala and ojas is matter ans substance in present world where every day new short of diseases are evolving. Different persons have different vyadhikshamatva which depends upon oja, bala, season, diet and regimen, anupana, rasa, jaatkarma etc. One should wisely adopt these into his lifestyle so as to make his body and mind strong enough to deal with all the physical and mental stresses of modern era.

SOURCES OF FUNDING
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.