Key result
Young women had greater femoral blood flow (P=0.002) and vascular conductance (P=0.041) responses to the cold pressor test compared with young men, despite similar sympathetic nerve activity.
Why the study?
Emerging evidence suggests sympathetic vasoconstriction is lower in young women, leading to the hypothesis that increases in MSNA during acute physiological stressors induce less vasoconstriction in young women compared to young men.
Do age and sex differences affect sympathetic and hemodynamic responses to acute physiological stressors like hypoxia and cold pressor test in healthy individuals?
Cross-Sectional (n=32)
Do age and sex differences affect sympathetic and hemodynamic responses to acute physiological stressors like hypoxia and cold pressor test in healthy individuals?
p-value: p=0.002
Young women exhibit paradoxical vasodilation in response to the cold pressor test compared to young men, despite similar sympathetic nerve activity responses.
May indicate attenuated sympathetic vasoconstriction in young women during stress; leaves open mechanisms and clinical relevance for larger trials.
Emerging evidence suggests that sympathetic vasoconstriction is lower in young women. We hypothesized that increases in muscle sympathetic nerve activity (MSNA) during acute physiological stressors induce less vasoconstriction in young women compared to young men. Healthy young men (n = 10, 27 ± 1 years), young women (n = 12, 25 ± 1 years), and older women (n = 10, 63 ± 6 years) performed the cold pressor test (hand in ice for 2 min) and continuous hypoxia (10% O2, 90% N2) for 5 min. MSNA, femoral blood flow velocity, heart rate, and blood pressure were acquired continuously. Femoral artery diameter was obtained every minute and used to calculate femoral blood flow, and femoral vascular resistance and conductance. MSNA responses to cold pressor test (P = 0.345) and hypoxia (P = 0.969) were not different between groups. Young women had greater femoral blood flow (P = 0.002) and vascular conductance (P = 0.041) responses to cold pressor test compared with young men. The femoral blood flow response to hypoxia was not different between the two sexes but the increase in femoral flow was attenuated in older women compared with younger women (P = 0.036). These data show that young women had paradoxical vasodilation to cold pressor test. The mechanisms responsible for the attenuated sympathetic vasoconstriction or for enhanced vasodilation in young women during the CPT require further investigation.
No takes yet. Share an insight, caveat, or question.
Miller et al. (2019) conducted a cross-sectional in Healthy (n=32). Cold pressor test and continuous hypoxia vs. Young men (for sex differences) and young women (for age differences) was evaluated on Muscle sympathetic nerve activity (MSNA), femoral blood flow, and vascular conductance responses (p=0.002). Young women had greater femoral blood flow (P=0.002) and vascular conductance (P=0.041) responses to the cold pressor test compared with young men, despite similar sympathetic nerve activity.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: