title: Sex difference in the influence of central blood volume mobilization on the exercise pressor response.
abstract: OBJECTIVE
  To determine the sex difference in the impact of central venous pressure (CVP) on the pressor response induced by ischemic handgrip exercise.
  
  
  METHODS
  Twelve young healthy individuals (six males, 25 ± 3 years) performed ischemic handgrip exercise during mild levels of lower body negative pressure (LBNP, -5 mmHg) and during a 10° head-down tilt (HDT) to lower and increase CVP, respectively. The protocol consisted of 3 min of baseline ischemia, followed by 2 min of isometric handgrip exercise at 35 % of maximal voluntary contraction force, and 2 min of post-exercise circulatory occlusion. Mean arterial pressure (MAP) was assessed continuously by finger plethysmography and CVP was estimated from the venous pressure of the non-exercising dependent arm.
  
  
  RESULTS
  Baseline CVP was greater during HDT than LBNP (8.4 ± 1.8 vs. 6.5 ± 1.8 mmHg, p < 0.01). MAP was greater during LBNP than HDT throughout the protocol (p = 0.05). During ischemic handgrip exercise, CVP increased in males but not in females (Group × protocol interaction: p = 0.01). A group × condition interaction was also observed for MAP, with males showing a greater MAP during LBNP than HDT (110 ± 2 vs. 103 ± 2 mmHg, p < 0.01).
  
  
  CONCLUSIONS
  Baseline CVP inversely affected the pressor response to handgrip exercise in all individuals, with a greater MAP response observed during LBNP than HDT. Increase in CVP in males may be due to a greater splanchnic vasoconstrictor response to ischemic handgrip exercise. Therefore, combined baseline CVP and changes in CVP likely contributed to the greater MAP response observed during LBNP in males.
authors.affiliation: School of Kinesiology, Faculty of Health Sciences, Western University, Room 3110 Thames Hall, London, ON, N6A 5B9, Canada.|Department of Kinesiology, University of Toledo, Toledo, OH, USA.
authors.forename: Sophie
authors.initials: S
authors.lastname: Lalande
authors.affiliation: School of Kinesiology, Faculty of Health Sciences, Western University, Room 3110 Thames Hall, London, ON, N6A 5B9, Canada.
authors.forename: Carly C
authors.initials: CC
authors.lastname: Barron
authors.affiliation: School of Kinesiology, Faculty of Health Sciences, Western University, Room 3110 Thames Hall, London, ON, N6A 5B9, Canada. kshoemak@uwo.ca.|Department of Physiology and Pharmacology, Western University, London, ON, Canada. kshoemak@uwo.ca.
authors.forename: J Kevin
authors.initials: JK
authors.lastname: Shoemaker
mesh_terms: D000328:Adult; D001794:Blood Pressure; D001810:Blood Volume; D015444:Exercise; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000502:physiology*; D012018:Reflex; D012737:Sex Factors
keywords: Cardiopulmonary receptors; Central blood volume; Handgrip exercise; Head-down tilt; Lower body negative pressure