10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 1 2013 (January - March) Aerobic training induces functional and dimensional changes in cardio vascular system, referred to as cardio-vascular conditioning. This article attempts to give the physiological basis of the changes that occur in CVS conditioning. The changes include a decrease in resting heart rate, enhanced stroke volume, enhanced cardiac output and an expanded atrio-venous O lessThan sub greaterThan 2 lessThan /sub greaterThan difference. The major factors that affect training improvement are initial fitness level, frequency, intensity &duration of exercise; and the type (mode) of training. Exercise need not be strenuous to obtain positive training adaptations. An exercise heart rate of 70% maximum represents moderate exercise with little or no discomfort. SANDHYA GUPTA, SEEMA KUMAR AND SUSHIL DOHARE Cardiovascular conditioning, Aerobic exercise, Resting heart rate 479-484