Variability and Heart Rate Kinetics During the Six-Minute Walk Test in Morbidly Obese Women – Effect of Aerobic Exercise Training after Gastric Bypass Surgery

All patients will undergo a clinical examination prior to the gastric bypass surgery (GBS) Roux-en-Y, which will be done by gastroenterologist and a cardiologist physician (anamnesis, resting 12-lead electrocardiogram, endoscopy and blood analysis used to determine hemoglobin, triglycerides, total cholesterol and fractions: low-density lipoprotein - LDL and high-density lipoprotein - HDL, fasting glucose and uric acid). In addition, anthropometric data, spirometric measurements, regular physical activity pattern, record of heart rate (HR) and R-R intervals during six-minute walk test (6MWT) will be collected 1 week before and 4 months after GBS. One month after surgery, the obese women will be randomly assigned to two groups: 1) trained (that will participate in a aerobic exercise training program for 3 months) and 2) untrained (will not participate in the exercise program). The aerobic exercise training program consist of five steps: 1) initial five minutes of stretching the upper and lower limbs (hamstrings, quadriceps, calves, shoulders) and diaphragmatic breathing and awareness of proper posture in front of a mirror in the position standing and sitting; 2) five minutes of heating on a treadmill at 3 km/h; 3) forty minutes of walking on treadmill with speed and inclination varying according to the behavior of HR. These forty minutes will be separated into four steps of 10 minutes each: 1 degree) intensity of exercise which the HR remained at 50% of HR maximal; 2 degrees) 60% of HR maximal; 3 degrees) 70% of HR maximal and 4 degrees) maintaining 70% of HR maximal; Note: Heart rate and blood pressure will be obtained at the end of each step; 4) recovery of one minute at 3 km/h and; 5) last step of ten minutes of the same initial stretching and diaphragmatic breathing. HR and blood pressure will be obtained at the beginning of the session, at the end of each step, recovery and at the end of session. The sessions will be held during one hour on alternate days: 3 times per week, for 12 weeks, a total of 36 sessions, a period of 3 months. The sessions will be performed individually and supervisioned by physiotherapist. The control group (eutrophic healthy women), will not perform the GBS and will not participate in the exercise program