Aerobic exercises builds stamina for sports and it is also the most important form of exercise for health, since it increases the efficiency of heart, circulation and muscles. In step aerobic exercises the heart rate increases substantially, but never reaches its maximum level. Obesity is usually defined in terms of excessive quantities of total body fat. It is a metabolic abnormality caused by excessive calorie intake. It refers to the condition of having excessive amount of total body fat i.e. above 20% for men and above 30% for women. Obesity leads to a) Diabetes b) Chronic heart diseases c) Deterioration of brain functions d) Acceleration of aging process and e) Deteriorated musculoskeletal system. Total of thirty obese women who works in various places of Chidambaram were selected at random for this study. They belonged to the age group of 25 to 30 years. The subjects were assigned to three groups (Group A, B, and C) with each group comprising of ten subjects. The results of this study shows that the varied aerobic exercises, namely aerobic and step aerobic exercises significantly improved the Vital Capacity of the obese women where as there is no significant decrease in their Resting Heart Rate.