Cardiovascular and perceptual responses to isometric exercise.
The purpose of this study was to investigate the effects of 3 intensities of isometric handgrip contractions on selected cardiovascular parameters and perception of effort, and to determine the relationship of these cardiovascular parameters to perception of effort. Seven healthy subjects were instructed to maintain 3-minute contractions in a randomized sequence, at 15, 25, and 35% of their maximal voluntary contractions (% MVC) while heart rate, systolic blood pressure, diastolic blood pressure and perception of effort were measured at 1-minute intervals. All 4 parameters were found to significantly increase (p less than 0.05) both as a function of contraction intensity (% MVC) and time. Correlation coefficients relating perception of effort to systolic blood pressure, diastolic blood pressure, and heart rate were 0.76, 0.64, and 0.63, respectively, suggested that perception of effort was a better predictor of systolic blood pressure than of diastolic blood pressure or heart rate. A 3-step multiple regression resulted in a cumulative r value of 0.82. Recommendations were made that perception of effort be further explored for clinical use during exercise prescription as an indicator of cardiovascular stress. By using a technique of perception of effort, patients could be taught to restrict activity to within a safe range of cardiovascular variability, rather than totally refrain from all forms of isometric activity.
D000328:Adult; D001794:Blood Pressure; D006225:Hand / Q000502:physiology; D006321:Heart / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D007537:Isometric Contraction; D010465:Perception / Q000502:physiology*; D005082:Physical Exertion; D012044:Regression Analysis