al'Absi M, Lovallo W R, McKey B, Sung B H, Whitsett T L, Wilson M F
Veterans Affairs Medical Center, Department of Psychiatry and Behavioral Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, USA.
Psychosom Med. 1998 Jul-Aug;60(4):521-7. doi: 10.1097/00006842-199807000-00021.
This study examined pituitary-adrenocortical responses to dietary doses of caffeine (3.3 mg/kg, equivalent to 2 to 3 cups of coffee), alone and combined with behavioral stress, in men at high risk versus low risk for hypertension. A randomized, double-blind, caffeine-placebo crossover design was used.
Adrenocorticotropic hormone (ACTH) and cortisol levels in plasma were assessed at rest and in response to 60-minutes of continuous work on a mental stressor (arithmetic) and a psychomotor task (reaction time) on four test sessions held on separate days.
Tasks alone caused greater ACTH and cortisol increases in high risk men than in the low risk group. Caffeine alone elevated ACTH and cortisol in both groups, with more immediate responses in the high risk group. Both groups showed significant ACTH and cortisol responses to caffeine plus tasks, with the high risk group showing more persistent elevations. The high risk group also showed the highest levels of ACTH and cortisol after caffeine plus tasks.
These findings demonstrate for the first time the combined effects of caffeine plus stress on ACTH and demonstrate greater corticosteroid effects in hypertension-prone men. As such, they may have implications for the dietary use of caffeine during periods of stress and in those at risk for hypertension.
本研究考察了高高血压风险与低高血压风险男性在单独摄入膳食剂量咖啡因（3.3毫克/千克，相当于2至3杯咖啡）以及同时结合行为应激情况下的垂体 - 肾上腺皮质反应。采用随机、双盲、咖啡因 - 安慰剂交叉设计。
在单独的四天进行的四个测试环节中，分别于静息状态以及在面对精神应激源（算术）和心理运动任务（反应时间）连续工作60分钟后，评估血浆中促肾上腺皮质激素（ACTH）和皮质醇水平。
单独的任务导致高风险男性的ACTH和皮质醇升高幅度大于低风险组。单独摄入咖啡因使两组的ACTH和皮质醇均升高，且高风险组的反应更迅速。两组对咖啡因加任务均表现出显著的ACTH和皮质醇反应，高风险组的升高更持久。高风险组在咖啡因加任务后的ACTH和皮质醇水平也最高。
这些发现首次证明了咖啡因加应激对ACTH的联合作用，并表明在易患高血压的男性中皮质类固醇作用更强。因此，它们可能对在应激期间以及高血压风险人群中咖啡因的膳食使用具有启示意义。
