等尺性掌握運動時の血圧，心拍数応答

抄録

　The purpose of this study was to measure blood pressure (SBP, DBP), heart rate (HR) and power spectrum (LF, HF) during four types of isometric handgrip exercises (IHG) with the different intensity and duration of time, to observe the function of the autonomic nervous system, and to clarify the response patterns induced to intensity and duration time for the assessment of hypertension. Eighteen male subjects aged 20 years old cooperated as volunteers, and performed four kinds of IHGs on one day for each subject. Experiment (Exp)ⅠandⅡconsisted of five intensities of IHG set for 20, 30, 40, 50 and 60 percent of maximal voluntary contraction (% MVC). ExpⅠgot intermittent (Int) loading contraction, the subjects keep gripping for ten seconds each % MVC with sufficient rest between IHG trials. ExpⅡ(continuous; Cont) got the same procedure as ExpⅠ, but no rest between trials that was done incrementaly. ExpⅠandⅡof IHG both tried from 20% MVC to 60% MVC. ExpⅢ(steady contraction; Sted, 40% MVC) got contraction keeping for forty seconds, and ExpⅣ(Sted, 30% MVC) kept the continuous grip for two minutes. Subjects accomplished all Exps in sitting on a chair. The load level (%) was checked by a picture on a personal computer in front of the subject by itself. During the IHG, arterial SBP, DBP, HR were continuously measured, and calculated LF and HF from the saved HR data with heart rate variability (HRV) software after these measurements. During IHG, the stronger of intensities or the longer of duration, the higher of SBP, DBP and HR were showed. Those differences were remarkably indicated on the Sted (Cont) than on the Imt trial. The pressor response of Cont IHG significantly correlated to SBP/DBP increase in Sted IHG, those makers during the Int IHG didn’t correlate significantly though. HF and LF power revealed enhancement of activity on the autonomic nerves induced to increase of hardness during IHG. According to above results, continuous (Cont) and/or steady (Sted) loadings seemed to be effective to evaluate hypertensive possibility in future much more feasible and validly than Imt loading so far the loading under 60% MVC.