TY - JOUR
T1 - Sympathetic neural and hemodynamic responses during cold pressor test in elderly blacks and whites
AU - Okada, Yoshiyuki
AU - Jarvis, Sara S.
AU - Best, Stuart A.
AU - Edwards, Jeffrey G.
AU - Hendrix, Joseph M.
AU - Adams-Huet, Beverley
AU - Vongpatanasin, Wanpen
AU - Levine, Benjamin D.
AU - Fu, Qi
N1 - Publisher Copyright:
© 2016 American Heart Association, Inc.
PY - 2016/5/1
Y1 - 2016/5/1
N2 - The sympathetic response during the cold pressor test (CPT) has been reported to be greater in young blacks than whites, especially in those with a family history of hypertension. Because blood pressure (BP) increases with age, we evaluated whether elderly blacks have greater sympathetic activation during CPT than age-matched whites. BP, heart rate, cardiac output, and muscle sympathetic nerve activity were measured during supine baseline, 2-minute CPT, and 3-minute recovery in 47 elderly (68±7 [SD] years) volunteers (12 blacks and 35 whites). Baseline BP, heart rate, cardiac output, or muscle sympathetic nerve activity did not differ between races. Systolic and diastolic BP and heart rate increased during CPT (all P<0.001) with no racial differences (all P>0.05). Cardiac output increased during CPT and ≤30 s of recovery in both groups, but was lower in blacks than whites. Muscle sympathetic nerve activity increased during CPT in both groups (both P<0.001); the increase in burst frequency was similar between groups, whereas the increase in total activity was smaller in blacks (P=0.030 for interaction). Peak change (Δ) in diastolic BP was correlated with Δ total activity at 1 minute into CPT in both blacks (r=0.78, P=0.003) and whites (r=0.43, P=0.009), whereas the slope was significantly greater in blacks (P=0.007). Thus, elderly blacks have smaller sympathetic and central hemodynamic (eg, cardiac output) responses, but a greater pressor response for a given sympathetic activation during CPT than elderly whites. This response may stem from augmented sympathetic vascular transduction, greater sympathetic activation to other vascular bed(s), or enhanced nonadrenergically mediated vasoconstriction in elderly blacks.
AB - The sympathetic response during the cold pressor test (CPT) has been reported to be greater in young blacks than whites, especially in those with a family history of hypertension. Because blood pressure (BP) increases with age, we evaluated whether elderly blacks have greater sympathetic activation during CPT than age-matched whites. BP, heart rate, cardiac output, and muscle sympathetic nerve activity were measured during supine baseline, 2-minute CPT, and 3-minute recovery in 47 elderly (68±7 [SD] years) volunteers (12 blacks and 35 whites). Baseline BP, heart rate, cardiac output, or muscle sympathetic nerve activity did not differ between races. Systolic and diastolic BP and heart rate increased during CPT (all P<0.001) with no racial differences (all P>0.05). Cardiac output increased during CPT and ≤30 s of recovery in both groups, but was lower in blacks than whites. Muscle sympathetic nerve activity increased during CPT in both groups (both P<0.001); the increase in burst frequency was similar between groups, whereas the increase in total activity was smaller in blacks (P=0.030 for interaction). Peak change (Δ) in diastolic BP was correlated with Δ total activity at 1 minute into CPT in both blacks (r=0.78, P=0.003) and whites (r=0.43, P=0.009), whereas the slope was significantly greater in blacks (P=0.007). Thus, elderly blacks have smaller sympathetic and central hemodynamic (eg, cardiac output) responses, but a greater pressor response for a given sympathetic activation during CPT than elderly whites. This response may stem from augmented sympathetic vascular transduction, greater sympathetic activation to other vascular bed(s), or enhanced nonadrenergically mediated vasoconstriction in elderly blacks.
KW - aging
KW - blood pressure
KW - cardiac output
KW - heart rate
KW - hypertension
UR - http://www.scopus.com/inward/record.url?scp=84961970548&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84961970548&partnerID=8YFLogxK
U2 - 10.1161/HYPERTENSIONAHA.115.06700
DO - 10.1161/HYPERTENSIONAHA.115.06700
M3 - Article
C2 - 27021009
AN - SCOPUS:84961970548
SN - 0194-911X
VL - 67
SP - 951
EP - 958
JO - Hypertension
JF - Hypertension
IS - 5
ER -