The possible combined effects of caffeine and exercise on blood pressure (BP) regulation were examined in 34 healthy, normotensive (BP less than 135/85 mm Hg) young men (mean age 27 +/- 3 years) in a placebo-controlled, double-blind crossover design. Each subject performed submaximal and symptom-limited maximal supine bicycle exercise 1 hour apart after ingestion of placebo or caffeine (3.3 mg/kg). Heart rate, BP, cardiac output and peripheral vascular resistance were compared for placebo and caffeine days. Postdrug baseline showed that caffeine increased systolic and diastolic BP and peripheral vascular resistance (p less than 0.001 for each) and decreased heart rate (p less than 0.01) but did not change stroke volume or cardiac output. BP and vascular resistance effects of caffeine remained during submaximal exercise resulting in an additive increase in BP while negative chronotropic effects of caffeine disappeared. At maximal exercise substantially more subjects (15 on caffeine vs 7 on placebo, p less than 0.02) had systolic BP greater than or equal to 230 mm Hg and/or greater than or equal to 100 mm Hg for diastolic BP. Plasma norepinephrine levels were not significantly different across days, but epinephrine was higher at maximal exercise and cortisol was increased post-drug and throughout maximal exercise on caffeine days. Data indicate that caffeine increases BP additively during submaximal exercise and may cause excessive BP responses at maximal exercise for some individuals. The pressor effects of caffeine appear to be due to increasing vascular resistance rather than cardiac output.

译文

:在安慰剂对照的34名健康,血压正常(血压低于135/85 mm Hg的年轻人)(平均年龄27 /-3岁)中,研究了咖啡因和运动对血压(BP)调节的可能联合作用,双盲交叉设计。服用安慰剂或咖啡因(3.3 mg / kg)后,每位受试者间隔1小时进行次最大和症状受限的最大仰卧自行车运动。比较安慰剂和咖啡因天的心率,血压,心输出量和外周血管阻力。药物后基线显示,咖啡因可增加收缩压和舒张压以及周围血管阻力(每个P值均小于0.001)和降低心率(P值均小于0.01),但并未改变中风量或心输出量。在次最大运动量下,咖啡因的血压和血管阻力作用仍然存在,从而导致血压增加,而咖啡因的负变时效作用消失了。在最大程度的运动中,更多的受试者(咖啡因为15,安慰剂为7,p小于0.02)的收缩压大于或等于230 mm Hg和/或舒张压大于或等于100 mm Hg。血浆去甲肾上腺素水平在各天之间无显着差异,但在最大运动量时,肾上腺素较高,而在咖啡因日后和整个最大运动量中,皮质醇增加。数据表明,咖啡因在次最大运动量时会增加BP,并且可能对某些个体在最大运动量时导致过度的BP反应。咖啡因的升压作用似乎是由于血管阻力增加而非心输出量增加所致。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录