TY - JOUR
T1 - Effects of alcohol on sympathetic activity, hemodynamics, and chemoreflex sensitivity
AU - Van De Borne, Philippe
AU - Mark, Allyn L.
AU - Montano, Nicola
AU - Mion, Decio
AU - Somers, Virend K.
PY - 1997/6
Y1 - 1997/6
N2 - Alcohol intake has been shown to worsen obstructive sleep apnea and increase nocturnal hypoxemia. The mechanisms of this action are unclear. Animal studies suggest that a reduction in chemoreflex sensitivity may be implicated. Using a double-blind, randomized, vehicle-controlled design, we tested the hypothesis that oral alcohol intake depresses chemoreflex sensitivity in humans. We examined the effects of oral alcohol intake (1.0 g/kg body wt) on blood pressure, heart rate, heart rate variability, muscle sympathetic nerve activity, forearm vascular resistance, and minute ventilation in 16 normal male subjects. Peripheral and central chemoreflex sensitivity were measured in response to hypoxia (n = 10) and hypercapnia (n=6), respectively. Plasma alcohol increased from 0 to 23.2±1.5 mmol/L (107±7 mg/dL) at 60 minutes and 20.2±1 mmol/L (93±4 mg/dL) at 85 minutes after alcohol intake (P<.0001). Alcohol induced an increase in heart rate from 59±2 to 66±2 beats per minute (P<.01) and increased the ratio of low- to high-frequency variability of heart rate (P<.05). Although alcohol increased sympathetic nerve activity by up to 239±22% of baseline values (P<.01), forearm vascular resistance after alcohol was lower than that after vehicle (P<.05). Blood pressure did not increase compared with the vehicle session. Oxygen saturation during hypoxia after alcohol was 4±1% lower than it was during hypoxia after vehicle (P<.05) although arterial blood PO2 was unchanged. Alcohol did not affect the cardiovascular, sympathetic, or ventilatory responses to either hypoxia or hypercapnia. Acute increases in plasma alcohol increase heart rate and sympathetic nerve activity; blood pressure is not increased, probably because of vasodilator effects of alcohol. Alcohol does not alter chemoreflex responses to hypoxia or hypercapnia; thus, alterations in chemoreflex sensitivity are unlikely to explain the effects of alcohol on sleep apnea. Alcohol may reduce the affinity of hemoglobin for oxygen.
AB - Alcohol intake has been shown to worsen obstructive sleep apnea and increase nocturnal hypoxemia. The mechanisms of this action are unclear. Animal studies suggest that a reduction in chemoreflex sensitivity may be implicated. Using a double-blind, randomized, vehicle-controlled design, we tested the hypothesis that oral alcohol intake depresses chemoreflex sensitivity in humans. We examined the effects of oral alcohol intake (1.0 g/kg body wt) on blood pressure, heart rate, heart rate variability, muscle sympathetic nerve activity, forearm vascular resistance, and minute ventilation in 16 normal male subjects. Peripheral and central chemoreflex sensitivity were measured in response to hypoxia (n = 10) and hypercapnia (n=6), respectively. Plasma alcohol increased from 0 to 23.2±1.5 mmol/L (107±7 mg/dL) at 60 minutes and 20.2±1 mmol/L (93±4 mg/dL) at 85 minutes after alcohol intake (P<.0001). Alcohol induced an increase in heart rate from 59±2 to 66±2 beats per minute (P<.01) and increased the ratio of low- to high-frequency variability of heart rate (P<.05). Although alcohol increased sympathetic nerve activity by up to 239±22% of baseline values (P<.01), forearm vascular resistance after alcohol was lower than that after vehicle (P<.05). Blood pressure did not increase compared with the vehicle session. Oxygen saturation during hypoxia after alcohol was 4±1% lower than it was during hypoxia after vehicle (P<.05) although arterial blood PO2 was unchanged. Alcohol did not affect the cardiovascular, sympathetic, or ventilatory responses to either hypoxia or hypercapnia. Acute increases in plasma alcohol increase heart rate and sympathetic nerve activity; blood pressure is not increased, probably because of vasodilator effects of alcohol. Alcohol does not alter chemoreflex responses to hypoxia or hypercapnia; thus, alterations in chemoreflex sensitivity are unlikely to explain the effects of alcohol on sleep apnea. Alcohol may reduce the affinity of hemoglobin for oxygen.
KW - alcohol
KW - anoxia
KW - autonomic nervous system
KW - blood pressure
KW - hypercapnia
KW - sympathetic nervous system
UR - http://www.scopus.com/inward/record.url?scp=0030991836&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030991836&partnerID=8YFLogxK
U2 - 10.1161/01.HYP.29.6.1278
DO - 10.1161/01.HYP.29.6.1278
M3 - Article
C2 - 9180629
AN - SCOPUS:0030991836
SN - 0194-911X
VL - 29
SP - 1278
EP - 1283
JO - Hypertension
JF - Hypertension
IS - 6
ER -