Inspiratory muscle high endurance protocol increases heart rate variability in myocardial revascularization patients

First, the voluntaries were submitted to anthropometric evaluation constituted by height and weight measurements (utilizing a stadiometer and a calibrated balance). On the same day, and in just a single session the respiratory muscle strength was evaluated by measurement of maximal inspiratory and expiratory pressure values, utilizing an aneroid manovacuometer. For this, each maneuver it was made at three repetitions with an interval of one minute between each repetition.The forced inspiratory maneuver was performed from residual volume and the forced expiratory maneuver was performed from total pulmonary capacity. After determination of the maximum respiratory pressures, an inspiratory muscle endurance protocol was applied and consisted of effort at two pressure levels: 60 and 80% of maximal inspiratory pressure. The loads were applied in a random order that had been chosen before the experiment. During the protocol the patient remained seated in a chair, using a nose clip and performed inspiratory effort utilizing the manovacuometer which had previously shown in the visor the value that corresponded to the individual’s pressure percentage of maximal inspiratory pressure (60 or 80%). Each effort level was performed for four minutes and the patient was oriented to make an inspiratory effort and maintain the equipment indicator on the demarcated line, which corresponded to the percentage being tested, for two seconds followed by expiration through the mouth for three seconds and which completed a total of 12 respiratory cycles per minute. To ensure that the maneuver was performed correctly and at the correct times for inspiration and expiration as previously instructed, one of the evaluators used a chronometer to give verbal commands to the patient. The protocol was made in just one day.