Effect of breathing instruction on blood pressure responses during isometric exercise

Twenty-seven normotensive, college-aged, female subjects were studied to assess the effects of training in breathing techniques on blood pressure during isometric contractions. Subjects were randomly and equally assigned to one of three training groups: 1) a group that was taught to perform a Valsalva maneuver during isometric efforts (VAL Group), 2) a group that was instructed to avoid performing the Valsalva maneuver (NO-VAL Group), and 3) a control group that was given no instructions (CONT Group). Prior to and following three breathing technique training sessions, two blood pressure measurements were made by amplified auscultation during 10 isometric contractions of the quadriceps femoris muscle with the leg positioned at 65 degrees of knee flexion. Breathing patterns were recorded on an impedance pneumograph. Data were submitted to a 2 X 2 X 3 (time X trial X group) multivariate analysis of covariance using resting systolic and diastolic blood pressures as covariates. A significant (p less than .05) time-x-group interaction revealed posttraining blood pressure response to isometric exercise had significantly decreased in the NO-VAL Group (163/120 vs 148/112 mm Hg), and had not significantly changed in the CONT Group (157/117 vs 153/117 mm Hg). These data illustrate that training to avoid the Valsalva maneuver may help attenuate the pressor response observed during isometric contractions and provide a means for safer patient exercise.