Caffeine-herbal ephedra combination increases resting energy expenditure, heart rate and blood pressure.
Caffeine-herbal ephedra combination increases resting energy expenditure, heart rate and blood pressure.
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咖啡因与草药麻黄的组合会增加静息能量消耗、心率和血压。
DOI：
10.1111/j.1440-1681.2005.04152.x
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Benowitz,NealL
中科院分区：
文献类型：
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作者：
Vukovich,MatthewD;Schoorman,Rana;Heilman,Chris;Jacob3rd,Peyton;Benowitz,NealL
1. 本研究的目的是确定摄入急性剂量的咖啡因和麻黄是否会增加 3 小时内的静息能量消耗 (REE)、心率 (HR) 和血压 (BP)。2。 进行了一项随机、双盲交叉研究，评估咖啡因（150 毫克）/草药麻黄（麻黄；20 毫克麻黄生物碱）与安慰剂的急性作用。总共 8 名健康受试者（4 名男性和 4 名女性），平均 (±SD) 年龄为 23.4 ± 0.8 岁（男性和女性平均年龄：分别为 25.3 ± 0.7 和 22.0 ± 0.7 岁）和 22.5 ± 3.1% 体脂（男性为 15.7 ± 1.2 和 27.6 ± 3.5% 体脂）和女性）被招募到该研究中。参与者是中度咖啡因使用者（大约 150–300 毫克/天）。3. 受试者在 12 小时禁食和 48 小时无咖啡因饮食后向实验室报告。在补充前测量静息能量消耗，并在补充后 3 小时内每 30 分钟测量 15 分钟。每 15 分钟获取一次心率和血压。测量 REE 后每 30 分钟采集一次血样，并分析咖啡因、麻黄碱、游离脂肪酸和葡萄糖。4。 到 3 小时时，咖啡因/麻黄试验的 HR 比基线高 22.7 ± 5.5%（P <0.05），而安慰剂组则高 8.9 ± 2.2%。 3 小时时，咖啡因/麻黄试验的收缩压比基线高 9.1 ± 2.2% (P <0.05)，而安慰剂试验的收缩压仅比基线高 1.9 ± 2.9%。咖啡因/麻黄组合对舒张压没有影响。安慰剂试验中最后 30 分钟的静息能量消耗高出 4.5 ± 2.5%，咖啡因/麻黄试验中高出 10.7 ± 2.5% (P <0.05)；与安慰剂试验相比，咖啡因/麻黄试验中的 REE 含量高出 8.5 ± 2.0% (P <0.05)。在安慰剂和咖啡因/麻黄试验中，游离脂肪酸随着时间的推移而增加（分别从 0.5 ± 0.05 至 0.63 ± 0.05 mEq/L 和从 0.48 ± 0.06L 至 0.8 ± 0.05 mEq/L）。5。 咖啡因和草药麻黄，剂量分别为 150 毫克和 20 毫克（麻黄碱），会导致 REE、HR 和 BP 显着升高。虽然能量消耗的增加很显着，但就减肥而言可以忽略不计。
1. The purpose of the present study was to determine whether the consumption of an acute dose of caffeine andMa Huangincreases resting energy expenditure (REE), heart rate (HR) and blood pressure (BP) over a 3 h period.2. A randomized, double‐blind cross‐over study was performed evaluating the acute effects of caffeine (150 mg)/herbal ephedra (Ma Huang; 20 mg ephedra alkaloids) versus a placebo. A total of eight healthy subjects (four males and four females) with a mean (±SD) age of 23.4 ± 0.8 years (mean ages for males and females: 25.3 ± 0.7 and 22.0 ± 0.7 years, respectively) and 22.5 ± 3.1% body fat (15.7 ± 1.2 and 27.6 ± 3.5% body fat for males and females, respectively) were recruited to the study. Participants were moderate caffeine users (approximately 150–300 mg/day).3. Subjects reported to the laboratory following a 12 h fast and 48 h of a caffeine‐free diet. Resting energy expenditure was measured prior to supplementation and for 15 min every 30 min for 3 h following supplementation. Heart rate and BP were obtained every 15 min. Blood samples were obtained every 30 min following the measurement of REE and analysed for caffeine, ephedrine, free fatty acids and glucose.4. By 3 h, HR was 22.7 ± 5.5% higher (P <0.05) than baseline for the caffeine/ephedra trial compared with 8.9 ± 2.2% higher for the placebo grou. At 3 h, systolic BP was 9.1 ± 2.2% higher (P <0.05) than baseline for the caffeine/ephedra trial compared with only 1.9 ± 2.9% different from baseline for the placebo trial. There was no effect of the caffeine/ephedra combination on diastolic BP. Resting energy expenditure during the last 30 min was 4.5 ± 2.5% higher in the placebo trial and 10.7 ± 2.5% higher (P <0.05) in the caffeine/ephedra trial; REE was 8.5 ± 2.0% higher (P <0.05) in the caffeine/ephedra trial compared with the placebo trial. Free fatty acids increased over time in the placebo and caffeine/ephedra trials (from 0.5 ± 0.05 to 0.63 ± 0.05 mEq/L and from 0.48 ± 0.06L to 0.8 ± 0.05 mEq/L, respectively).5. Caffeine and herbal ephedra, at doses of 150 mg and 20 mg (ephedrine), respectively, result in a significant elevation in REE, HR and BP. Although significant, the increase in energy expenditure is negligible in terms of weight loss.