Pincomb G A, Wilson M F, Sung B H, Passey R B, Lovallo W R
Medical Research Service, Veterans Affairs Medical Center, Oklahoma City, OK 73104.
Am Heart J. 1991 Oct;122(4 Pt 1):1107-15. doi: 10.1016/0002-8703(91)90479-2.
Caffeine-induced blood pressure elevations are well documented in habitual consumers, occurring through both vasoconstrictive and cardiostimulatory actions. Whether caffeine hinders pressor regulation during exercise has been uncertain, particularly in those at risk for hypertension. Thus effects of caffeine versus placebo were studied during supine bicycle exercise in healthy men (ages 20 to 35). Hypertension risk was defined during screening: high risk (HRISK) = 135 to 154/85 to 94 mm Hg plus parental hypertension (n = 20); low risk (LRISK) = less than or equal to 132/84 mm Hg and no parental hypertension (n = 14). Exaggerated pressor responses (greater than or equal to 230/100 mm Hg) seen during exercise after placebo identified a subgroup of seven HRISKs indistinguishable at rest from the remaining HRISK men. This subgroup showed a larger resting diastolic response to caffeine (p less than 0.05) than LRISKs and other HRISKs. Compared with placebo, caffeine increased the number of LRISK (0% to 36%) and HRISK (35% to 50%) men reaching abnormal exercise blood pressures, and blunted normal increments in cardiac index at higher workloads among HRISK men (p = 0.05). Thus restriction of caffeine before exercise might benefit persons with either risk for hypertension or unusual sensitivity to caffeine.
咖啡因导致血压升高在习惯性摄入者中已有充分记录，其通过血管收缩和心脏刺激作用实现。咖啡因在运动期间是否会阻碍压力调节尚不确定，尤其是在高血压风险人群中。因此，在健康男性（年龄20至35岁）仰卧位自行车运动期间研究了咖啡因与安慰剂的效果。在筛查期间定义高血压风险：高风险（HRISK）=135至154/85至94毫米汞柱加上父母有高血压（n=20）；低风险（LRISK）=小于或等于132/84毫米汞柱且父母无高血压（n=14）。安慰剂后运动期间出现的过度升压反应（大于或等于230/100毫米汞柱）确定了一个由7名HRISK组成的亚组，其静息状态与其余HRISK男性无法区分。该亚组对咖啡因的静息舒张压反应比LRISK和其他HRISK更大（p<0.05）。与安慰剂相比，咖啡因增加了达到异常运动血压的LRISK（从0%增至36%）和HRISK（从35%增至50%）男性的数量，并且在较高工作量时使HRISK男性的心脏指数正常增加变钝（p=0.05）。因此，运动前限制咖啡因摄入可能有益于有高血压风险或对咖啡因异常敏感的人群。
