目的:习惯性喝咖啡无处不在,尽管有短暂的高血压作用,但通常被认为是安全的。我们的目的是确定交感神经系统在高血压反应中的作用。
方法:在单中心交叉研究中,医疗护理人员在食用标准咖啡(浓缩咖啡)后进行了研究,水和脱咖啡因咖啡(defaff)以随机顺序给予至少1个月间隔。血浆咖啡因水平,平均动脉压,心率,记录总外周阻力和肌肉交感神经活动.使用爆发发生率和RR间期变化对自发性血压波动进行评估。
结果:共招募16名受试者(平均[±标准误差]年龄34.4±2岁;44%为女性)参与研究。在十个受试者中研究了三个特工,并在六个受试者中研究了两个代理人。在饮用标准咖啡后的120分钟内,与水(101±1mmHg;p=0.066)和decaff(100±1mmHg;p=0.016)相比,平均(±SE)血浆咖啡因水平从2.4±0.8增加到21.0±4µmol/L,动脉压增加到103±1mmHg.与水(107±4;p=0.01)和脱氟(109±4;p=0.02)相比,咖啡后同期的外周阻力增加到基线水平的120±4%。饮用咖啡和脱咖啡因后心率均较低:与水相比,心率为62±1bpm(64bpm;分别为p=0.01和p=0.02)。咖啡后迷走神经压力反射活性保持稳定,但是交感神经活动减少了,尽管压力反射活性从-2.2±0.1下降到-1.8±0.1爆发/100次搏动/mmHg,但爆发频率为96±3%,与水(106±3%;p=0.04)和decaff(112±3%;p=0.001)相比,爆发频率为96±3%,与水(p=0.009)和脱盐水(p=0.004)相比。
结论:对咖啡的高血压反应继发于外周血管收缩,但这不是由交感神经活动增加介导的。这些结果可以解释为什么习惯性喝咖啡是安全的。
Habitual coffee drinking is ubiquitous and generally considered to be safe despite its transient hypertensive effect. Our purpose was to determine the role of the sympathetic nervous system in the hypertensive response.
In a single-centre crossover
study, medical caregivers were studied after consumption of standard coffee (espresso), water and decaffeinated coffee (decaff) given in random order at least 1 month apart. Plasma caffeine levels, mean arterial pressure, heart rate, total peripheral resistance and muscle sympathetic activity were recorded.
Baroreflex activity was assessed using burst incidence and RR interval changes to spontaneous blood pressure fluctuations.
A total of 16 subjects (mean [± standard error] age 34.4 ± 2 years; 44% female) were recruited to the
study. Three agents were studied in ten subjects, and two agents were studied in six subjects. Over a 120-min period following the consumption of standard coffee, mean (± SE) plasma caffeine levels increased from 2.4 ± 0.8 to 21.0 ± 4 µmol/L and arterial pressure increased to 103 ± 1 mmHg compared to water (101 ± 1 mmHg; p = 0.066) and decaff (100 ± 1 mmHg; p = 0.016). Peripheral resistance in the same period following coffee increased to 120 ± 4% of the baseline level compared to water (107 ± 4; p = 0.01) and decaff (109 ± 4; p = 0.02). Heart rate was lower after both coffee and decaff consumption: 62 ± 1 bpm compared to water (64 bpm; p = 0.01 and p = 0.02, respectively). Cardio-vagal
baroreflex activity remained stable after coffee, but sympathetic activity decreased, with burst frequency of 96 ± 3% versus water (106 ± 3%; p = 0.04) and decaff (112 ± 3%; p = 0.001) despite a fall in
baroreflex activity from - 2.2 ± 0.1 to - 1.8 ± 0.1 bursts/100 beats/mmHg, compared to water (p = 0.009) and decaff (p = 0.004).
The hypertensive response to coffee is secondary to peripheral vasoconstriction but this is not mediated by increased sympathetic nerve activity. These results may explain why habitual coffee drinking is safe.