Performance and Sport Rehabilitation Laboratory (DEPORSALUD), Faculty of Sports Sciences, University of Castilla-La Mancha, Avenida Carlos III s/n, 45071 Toledo, Spain.
Faculty of Health Sciences, Universidad Francisco de Vitoria, 28223 Pozuelo de Alarcón, Spain.
Nutrients. 2024 May 7;16(10):1405. doi: 10.3390/nu16101405.
This study aimed to analyse the placebo effect associated with a high dose of caffeine (9 mg/kg) on heart rate and its variability and on strength tests.
18 participants experienced in strength training (19.7 ± 2.3 years; 72.2 ± 15.0 kg; 169.6 ± 9.0 cm) performed two days of trials (caffeine-informed/placebo-ingested (placebo) and non-ingested (control)). Firstly, heart rate and its variability were measured while participants lay down for 15 min. After that, bench press and squat tests were performed at 3 different loads (50%, 75% and 90% of 1RM). Perception of performance, effort and side effects were also evaluated.
no differences were found in the vast majority of strength variables analysed. Resting heart rate decreased in the placebo trial (60.39 ± 10.18 bpm control vs. 57.56 ± 9.50 bpm placebo, = 0.040), and mean RR increased (1020.1 ± 172.9 ms control vs. 1071.5 ± 185.7 ms placebo, = 0.032). Heart rate variability and perception of performance and effort were similar between conditions ( > 0.05 in all cases). Side effects such as activeness and nervousness were reported while consuming the placebo.
the placebo effect did not modify performance in the majority of the strength test variables, HRV and perception of performance and effort. However, resting heart rate was reduced, mean RR increased, and some side effects appeared in the placebo trial.
本研究旨在分析高剂量咖啡因（9 毫克/千克）对心率及其变异性以及力量测试的安慰剂效应。
18 名有力量训练经验的参与者（19.7 ± 2.3 岁；72.2 ± 15.0 千克；169.6 ± 9.0 厘米）进行了两天的试验（咖啡因知情/安慰剂摄入（安慰剂）和未摄入（对照））。首先，参与者躺下 15 分钟时测量心率及其变异性。之后，在 3 个不同负荷（1RM 的 50%、75%和 90%）下进行卧推和深蹲测试。还评估了对表现、努力和副作用的感知。
在分析的绝大多数力量变量中未发现差异。静息心率在安慰剂试验中下降（60.39 ± 10.18 bpm 对照 vs. 57.56 ± 9.50 bpm 安慰剂， = 0.040），平均 RR 增加（1020.1 ± 172.9 ms 对照 vs. 1071.5 ± 185.7 ms 安慰剂， = 0.032）。在两种情况下，心率变异性和表现及努力的感知相似（所有情况下 > 0.05）。摄入安慰剂时报告了一些副作用，如活跃和紧张。
安慰剂效应并未改变大多数力量测试变量、HRV 和表现及努力的感知中的表现。然而，静息心率降低，平均 RR 增加，安慰剂试验中出现了一些副作用。
