Lane J D, Manus D C
Department of Psychiatry, Duke University Medical Center, Durham, North Carolina 27710.
Psychosom Med. 1989 Jul-Aug;51(4):373-80. doi: 10.1097/00006842-198907000-00001.
Although habitual caffeine users ingest the drug repeatedly throughout each day, the persistence of caffeine's known cardiovascular effects with such repeated use has not been investigated. Blood pressure and heart rate were measured under resting conditions in 10 healthy, male coffee or tea drinkers for 2 hours following a pretreatment dose of caffeine (125 mg) on two separate days after overnight abstinence. Either a second caffeine dose or placebo was administered and measurements continued for 1.5 hours. Compared to placebo, the second dose of caffeine produced significant increases in heart rate and diastolic and mean arterial, but not systolic, blood pressures. The results suggest that the cardiovascular effects of caffeine may persist throughout the day with repeated administration of moderate amounts of caffeine. Habitual caffeine use does not necessarily lead to complete tolerance, which suggests that caffeine's cardiovascular effects could contribute to an increased risk of cardiovascular disease.
尽管有咖啡因使用习惯的人每天会多次摄入这种药物，但咖啡因这种反复使用后已知的心血管效应的持续性尚未得到研究。在10名健康男性咖啡或茶饮用者过夜禁食后的两个不同日子里，在给予预处理剂量的咖啡因（125毫克）后，于静息状态下测量其血压和心率2小时。之后要么给予第二剂咖啡因，要么给予安慰剂，并继续测量1.5小时。与安慰剂相比，第二剂咖啡因使心率、舒张压和平均动脉压显著升高，但收缩压未升高。结果表明，反复给予适量咖啡因后，咖啡因的心血管效应可能会持续一整天。习惯性使用咖啡因不一定会导致完全耐受，这表明咖啡因的心血管效应可能会增加心血管疾病的风险。
