Yeragani Vikram K, Krishnan Siddartha, Engels Hermann J, Gretebeck Randall
Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan, USA.
Depress Anxiety. 2005;21(3):130-4. doi: 10.1002/da.20061.
Caffeine intake is associated with an increase in heart rate (HR) variability. This study sought to examine the effects of caffeine on HR variability measures before and during progressive exercise in 11 healthy volunteers in a double-blind randomized and counterbalanced placebo-controlled paradigm. As expected, there were significant increases in HR and decreases in HR variability after exercise during both placebo and caffeine conditions; however, pre-exercise caffeine condition was associated with a significant increase of HR variability, especially in the high-frequency range (0.15-0.5 Hz), and also approximate entropy (APEN), which is usually attributed to cardiac vagal function. But during progressive exercise, caffeine intake resulted in a greater decrease of HF power as well as HR APEN. Caffeine also was associated with significantly higher LF power during exercise compared to the placebo condition. These results suggest that caffeine may have different effects on HR variability at rest, compared to exercise. These findings may have implications for patients with cardiac illness and anxiety, depression, and psychotic disorders who use beverages containing excessive caffeine.
咖啡因摄入与心率（HR）变异性增加有关。本研究旨在采用双盲随机、平衡、安慰剂对照范式，检测11名健康志愿者在进行渐进性运动前和运动期间咖啡因对HR变异性指标的影响。正如预期的那样，在安慰剂和咖啡因条件下，运动后HR均显著增加，HR变异性均降低；然而，运动前咖啡因条件与HR变异性显著增加有关，尤其是在高频范围（0.15 - 0.5赫兹），以及近似熵（APEN），近似熵通常归因于心迷走神经功能。但在渐进性运动期间，摄入咖啡因导致高频功率以及HR的APEN下降幅度更大。与安慰剂条件相比，运动期间咖啡因还与显著更高的低频功率有关。这些结果表明，与运动时相比，咖啡因在静息状态下可能对HR变异性有不同影响。这些发现可能对患有心脏病以及使用含过量咖啡因饮料的焦虑、抑郁和精神障碍患者具有启示意义。
