title: Arterial blood pressure response to head-up tilt test and orthostatic tolerance in nurses.
abstract: OBJECTIVE
  High tolerance to postural changes was examined in nurses.
  
  
  METHODS
  Twelve female nurses and 12 healthy controls underwent a 70° head-up tilt (HUT) test for 10 min. Blood pressure (BP), heart rate (HR), pulse pressure, and hormone levels were measured. Baroreceptor sensitivity (BRS) was calculated using a sequence technique.
  
  
  RESULTS
  HR increased during HUT in both subject groups, with no difference between groups. Systolic BP was rapidly increased by HUT in both subject groups, and was higher in the nurse group than in the control group during the first 2 min of HUT. Pulse pressure decreased during 1-2.5 min of HUT in the control group, but there was no decrease in the nurse group. BRS was decreased by HUT in the nurse group, while it tended to be decreased in the control group. Both during baseline and HUT, BRS was lower in the nurse group than in the control group. Plasma noradrenaline increased with HUT, and the increase was greater in the nurse group than in the control group.
  
  
  CONCLUSIONS
  Although nurse subjects had a lower BRS during HUT than control subjects, they were able to effectively maintain BP during HUT, suggesting that nurse subjects had higher orthostatic tolerance. The better maintenance of BP in nurse subjects appeared to be associated with a compensatory mechanism other than the arterial baroreflex and/or a hemodynamic mechanism.
authors.affiliation: Department of Physiology, Aichi Medical University, Nagakute, Aichi, 480-1195, Japan, onizuka@aichi-med-u.ac.jp.
authors.forename: Chisato
authors.initials: C
authors.lastname: Onizuka
authors.forename: Yuki
authors.initials: Y
authors.lastname: Niimi
authors.forename: Motohiko
authors.initials: M
authors.lastname: Sato
authors.forename: Junichi
authors.initials: J
authors.lastname: Sugenoya
mesh_terms: D000328:Adult; D017704:Baroreflex; D001794:Blood Pressure; D004244:Dizziness / Q000209:etiology*; D005260:Female; D006339:Heart Rate; D006728:Hormones / Q000097:blood; D006801:Humans; D009726:Nurses; D011187:Posture; D018667:Tilt-Table Test; D055815:Young Adult
chemical_list: D006728:Hormones