title: Initial cardiovascular response on change of posture from squatting to standing.
abstract: The immediate cardiovascular responses on active change from the squatting (control) to the standing position differ from those obtained in the lying-to-standing manoeuvre. Without exception, the first beat after changing from squatting to standing showed a decrease in systolic, diastolic and mean pressure by 2.0 +/- 1.1 kPa (14.6 +/- 8.3 mm Hg), 1.4 +/- 1.7 kPa (10.6 +/- 12.6 mm Hg) and 1.9 +/- 1.0 kPa (13.9 +/- 7.3 mm Hg), respectively. During the 4th or 5th pulse after standing the pulse pressure was significantly higher than when lying (P less than 0.01). Mean pressure reached a minimum of 7.7 +/- 1.9 kPa (57.8 +/- 14.4 mm Hg) after 7.1 +/- 1.1 s. Thereafter the blood pressure increased to a new level within about 15 s. 11 of 16 subjects demonstrated a biphasic heart rate (HR) response. The maximum HR was reached after 11.0 +/- 2.4 s of standing. In all experiments, the peaks in HR were distinctly delayed after the blood pressure dips. We conclude that an arterial baroreflex could be implicated in the immediate HR increase after a squatting-to-standing manoeuvre. The subsequent time course of the initial HR response, however, might be induced by other mechanisms.
authors.affiliation: Carl Ludwig Institute of Physiology, Medical Faculty, Karl Marx University, Leipzig, German Democratic Republic.
authors.forename: F
authors.initials: F
authors.lastname: Rossberg
authors.forename: J
authors.initials: J
authors.lastname: Penaz
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D011187:Posture; D011311:Pressoreceptors / Q000502:physiology*; D012018:Reflex