咖啡摄入前后心率变异性的对比研究

目的研究中等剂量咖啡摄入对青年受试者心率变异性的影响,明确咖啡对心脏自主神经活性的作用。方法无咖啡因摄入习惯的16名健康青年受试者(身高167 cm±7.2 cm、体重61.3 kg±6.3kg、年龄24.9岁±2.8岁)参与本项研究,在摄入含6 mg/kg咖啡因的咖啡饮品后,于8:40~10:45应用动态心电图记录仪(Holter)进行咖啡摄入前后心电信号的采集及心率(heart rate,HR)和心率变异性指标的分析。心率变异性指标包括R-R间期标准差(SDNN)、相邻R-R间期差值的均方根值(r MSSD)、相邻的R-R间期之差大于50 ms的心搏数占总心搏数的百分比(PNN50)、标化低频(normalized low frequency power,LFnorm)、标化高频(normalized high frequency power,HFnorm)、低频功率(low frequency,LF)与高频功率(high frequency,HF)的比值(LF/HF)。结果饮用咖啡后,心率、心率变异性指标均发生改变且具有统计学意义,HR、LFnorm和LF/HF分别降低了7.5%、17%和35%。r MSSD、PNN50和HFnorm分别提高了82%、80%和58%。其中HR及LF/HF随着时间的变化趋势最明显。HRV参数在饮用咖啡前后的差值ΔLF与ΔHF,ΔLF与ΔLF/HF均显著相关,相关系数为-0.980和0.903。结论中等剂量咖啡可引起心率变异性的改变和心率的降低,抑制交感神经活性,提高副交感神经活性。

Effect of coffee on heart rate variability

Objective To study the effect of coffee on heart rate variability( HRV) in young adults in order to determine the effect of coffee ingestion on cardiac autonomic nervous system ( ANS ) activity. Methods There were sixteen healthy young nonhabitual caffeine consumers as subjects enrolled in this study( height 167 cm±7. 2 cm,body mass 61. 3 kg±6. 3 kg,age 24. 9 years±2. 8 years). Coffee ingested by the subjects was 6 mg/kg caffeine as moderate dosage. And the dynamic electrocardiogram signals were recorded and analyzed with a dynamic Holter before and after coffee ingestion during 8:40 to 10:45 in the morning. HRV parameters included the mean standard deviation of all NN intervals,the root mean square of successive differences(rMSSD),the percentage of successive NN intervals differing >50 ms ( PNN50 ) , the normalized low frequency power (LFnorm),the normalized high frequency power(HFnorm),and the low frequency(LF)and high frequency ( HF) ratio LF/HF. Results There were significant differences before and after taking coffee in HRV parameters and the mean heart rate ( HR ) . HR, LFnorm, LF/HF decreased 7. 5％, 17％ and 35％, respectively. rMSSD, PNN50 and HFnorm increased 82％, 80％ and 58％, respectively. HR and LF/HF changed more obviously over time after taking coffee.ΔLF was highly correlated with ΔHF and ΔLF/HF with the correlation coefficients of -0.980 and 0.903. Conclusions Coffee with moderate dosage caffeine can cause the change of HRV and the decrease of HR, inhibit sympathetic nervous system activity(SNSA),and enhance parasympathetic nervous system activity(PNSA).