Sex and vasodilator responses to hypoxia at rest and during exercise

Darren P. Casey, John R A Shepherd, Michael Joseph Joyner

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

In humans, ß-Adrenergic receptor activation causes a substantial portion of hypoxic vasodilation in skeletal muscle at rest and during forearm exercise. Recent evidence suggests that ß-Adrenergic receptors are either more sensitive or upregulated in young women vs. men. Therefore, we examined whether sex influences hypoxic vasodilation in 31 young subjects (15 women/16 men; 26 ± 1 yr). We also examined whether potential sex-related differences existed in a group of older adults (6 women/5 men; 61 ± 2 yr). All subjects performed forearm exercise at 10 and 20% of maximum under normoxic and hypoxic [80% arterial O2 saturation (SO2)] conditions. Forearm vascular conductance (FVC; ml·min-1·100 mmHg -1) was calculated from blood flow (ml/min) and blood pressure (mmHg). At rest, young women demonstrated a greater vasodilator response to hypoxia compared with men (39 ± 12 vs. 13 ± 6%, P < 0.05). The absolute compensatory vasodilator response (hypoxic FVC-normoxic FVC) during exercise was similar between sexes, but the relative change was greater in young women at 10% (28 ± 5 vs. 17 ± 3%, P < 0.05) and 20% exercise (29 ± 4% vs. 15 ± 3%, P < 0.01). Additionally, the absolute changes in vasodilation after normalizing the response to forearm volume or workload were greater in young women during exercise (P < 0.05). Interestingly, the compensatory vasodilator responses between older women and men were similar at 10 and 20% exercise, regardless of whether the response is expressed as absolute, relative, or absolute change normalized for forearm volume or workload (P = 0.054-0.97). Our data suggest that the compensatory vasodilator response to hypoxic exercise is greater in young women compared with men. However, sex-specific differences appear to be lost with aging.

Original languageEnglish (US)
Pages (from-to)927-936
Number of pages10
JournalJournal of Applied Physiology
Volume116
Issue number7
DOIs
StatePublished - Apr 1 2014

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Vasodilator Agents
Exercise
Forearm
Vasodilation
Workload
Sex Characteristics
Adrenergic Receptors
Hypoxia
Blood Vessels
Skeletal Muscle
Blood Pressure

Keywords

  • Exercise
  • Hypoxia
  • Sex
  • Vasodilation

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Medicine(all)

Cite this

Sex and vasodilator responses to hypoxia at rest and during exercise. / Casey, Darren P.; Shepherd, John R A; Joyner, Michael Joseph.

In: Journal of Applied Physiology, Vol. 116, No. 7, 01.04.2014, p. 927-936.

Research output: Contribution to journalArticle

Casey, Darren P. ; Shepherd, John R A ; Joyner, Michael Joseph. / Sex and vasodilator responses to hypoxia at rest and during exercise. In: Journal of Applied Physiology. 2014 ; Vol. 116, No. 7. pp. 927-936.
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