 4 consecutive days with volunteers between the first and fourth postoperative period of cardiac valve replacement. The volunteers are randomized into 2 groups: the Control Group submitted to cardiac rehabilitation protocol of the hospital where it will be conducted the study, which consists of respiratory and metabolic exercises. The second group, called Early Mobilization Group in addition to the aforementioned exercises will be added exercise in cycle ergometer. For the implementation of rehabilitation protocol in the early mobilization group volunteers will be placed in a sitting position in the bed with the backrest raised to 45 . The exercise in cycle ergometer will be held for 20 minutes on four consecutive days of active mode, the training load shall be such that the voluntary maintained throughout training a level of fatigue, maintaining level of heart rate predicted for age increased by 70 and 1 w cm2 every minute to keep the parameter within the standards. The evaluation of heart rate variability with the Polar monitor RS800CX brand model before surgery was performed first postoperative day and fifth postoperative day in the control groups and early mobilization. 