Objective: To study the efficacy of yoga on Guna (yogic personality measure) and general health in normal adults.
Methods: Of the 1228 persons who attended introductory lectures, 226 subjects aged 18–71 years, of both sexes, who satisfied the inclusion and exclusion criteria and who consented to participate in the study were randomly allocated into two groups. The Yoga(Y) group practised an integrated yoga module that included asanas, pranayama, meditation, notional correction and devotional sessions. The control group practised mild to moderate physical exercises (PE). Both groups had supervised practice sessions (by trained experts) for one hour daily, six days a week for eight weeks. Guna (yogic personality) was assessed before and after eight weeks using the self-administered Vedic Personality Inventory (VPI) which assesses Sattva (gentle and controlled), Rajas (violent and uncontrolled) and Tamas (dull and uncontrolled). The general health status (total health), which includes four domains namely somatic symptoms (SS), anxiety and insomnia (AI), social dysfunction (SF) and severe depression (SP), was assessed using a General Health Questionnaire (GHQ).
Results: Baseline scores for all the domains for both the groups did not differ signifi cantly (P > 0.05, independent samples t test). Sattva showed a signifi cant difference within the groups and the effect size was more in the Y than in the PE group. Rajas showed a signifi cant decrease within and between the groups with a higher effect size in the PE group. Tamas showed signifi cant reduction within the PE group only. The GHQ revealed that there was signifi cant decrease in SS, AI, SF and SP in both Y and PE groups (Wilcoxcon Singed Rank t test). SS showed a significant difference between the groups (Mann Whitney U Test).
Conclusions: There was an improvement in Sattva in both the Yoga and control groups with a trend of higher effect size in Yoga; Rajas reduced in both but signifi cantly better in PE than in Yoga and Tamas reduced in PE. The general health status improved in both the Yoga and control groups.

The present age of speed and competition has increased the stresses and strains resulting in an increasing prevalence of life style-related health problems.[1] One of the increasingly popular tools to overcome this new challenge is physical activity. There is growing evidence that has established the benefits of physical exercises in preventing life style-related diseases[2] such as primary prevention of diabetes,[3] prevention of cardiac diseases through control over major risk factors such as smoking, lipids, obesity and stress,[4] better quality of life of cancer patients,[5] positive health in normal persons through better physical fitness[6] and stress reduction.[7] Yoga which is considered to be a tool for both physical and mental development of an individual is being recognized around the globe only in the last century although it has been practised in India over several centuries to promote positive health and well being. It gives solace for the restless mind and can give great relief to the sick.[8,9] It has become quite fashionable even for the common man to keep fit.[10] Some use yoga for developing memory, intelligence and creativity.[11] With its multifold advantages, yoga is becoming a part of school education.[12] Specialists use it to unfold deeper layers of consciousness in their move towards spiritual perfection.[13] With growing scientific evidence, yoga is emerging as an important health behavior-modifying practice to achieve states of health, both at physical and mental levels. Several studies have demonstrated the beneficial effects of yoga on health behavior in many life style-related somatic problems such as hypertension,[14] bronchial asthma,[15] diabetes[16] including some psychiatric conditions such as anxiety neurosis[17] and depressive illness[18] etc.
The philosophy of yoga believes that somatic problems are nothing but a manifestation of an imbalance between three Gunas (Sattva, Rajas and Tamas) that go to constitute the body-mind complex of the individual.[19] Further, in the famous scriptural text, the Gita; a guna indicates a specific behavior style. Sattva is symbolized by purity, wisdom, bliss, serenity, love of knowledge, spiritual excellence and other noble and sublime qualities. Rajas is symbolized by egoism, activity, restlessness and hankering after mundane things like wealth, power, valor and comforts.
Tamas is related to qualities such as bias, heedlessness and inertia, perversion in taste, thought and action.[20] Ill health occurs if Rajas or Tamas become dominant and the individual gets habituated to either of these response patterns. Furthermore, the Gita goes on to analyze the state of mind and says that when one is dominated by these two gunas, the individual loses mastery over the uncontrolled, speeded-up loop of sentences of the internal dialogue, which shows up as upsurges of emotions and impulsive behavior. In an ideal state of perfect health, man has the complete freedom to use any of these three patterns (Satva, Rajas or Tamas) of responses. Hence, the degree of positive health can be measured by a tool that can grade these three patterns of behavior.[19] The tool can be used for assessment of interventions used for treatment or prevention of diseases as well as for promotion of positive health. The Vedic Personality Inventory (VPI)[21] is a valid and reliable inventory that can measure the three patterns of behavior. While Yoga is getting popular, the relative roles of yoga and physical exercises have not been studied on gunas and health. Hence, the present study was designed to assess the changes in the personality and overall health status after yoga as compared to physical exercise in a randomized controlled study in normal healthy volunteers.