Liu Hou-Shao, Okada Takashi, Mitsuya Hiroku, Hsieh Meng-Hung, Hou Chien-Wen, Chang Chih-Chun, Chiu Chih-Hui
Institute of Sports Sciences, University of Taipei, Taipei, Taiwan.
Faculty of Sport Science, Nippon Sport Science University, Tokyo, Japan.
BMC Sports Sci Med Rehabil. 2025 Apr 26;17(1):98. doi: 10.1186/s13102-025-01144-z.
The purpose of this study was to investigate effects of caffeinated chewing gum-induced sympathetic activation and diuretic effect on the rapid rate of weight loss in bodybuilders.
Fourteen current elite natural bodybuilding athletes (age: 26 ± 7 years old; BMI: 26.9 ± 7.1 kg/m; muscle mass: 40.4 ± 7.1 kg; %body fat: 15.5 ± 4.4%) were included as participants. After confirming the specific gravity of the urine, the participants chewing either caffeinate Gum containing 3 mg/kg of caffeine (CAF trial) or placebo gum without containing caffeine (PL trial) for 10 min, with a randomized, double-blind, cross-over design. Following a 15-minute period of rest, the participants undergo a weight reduction process by engaging in cycling on a bicycle with an adjustable resistance level. The cycling is performed until the participant has experienced a dehydration state, resulting in a weight reduction of 2% of their initial body weight. Record time, heart rate, heart rate variability (HRV) urination volume and energy expenditure from exercise to completion of dehydration.
The urination volume (P = 0.040) and sympathetic activation were significantly higher in the CAF trial than in the PL trial during dehydration exercise (P < 0.05). Time to dehydration (P = 0.024) and the rating of perceived exertion (RPE) score during exercise were significantly lower in the CAF trial than in the PL trial. There were no significant differences in heart rate and energy expenditure during dehydration exercise between the two trials (P < 0.05).
This study found that chewing caffeinated gum increased sympathetic nerve activity and accelerated dehydration in bodybuilders.
This study was registered in ClinicalTrials.gov (Date: 04/08/2024; ID "NCT06431035"; https://register.
gov ).
本研究旨在调查含咖啡因口香糖引起的交感神经激活和利尿作用对健美运动员快速减重的影响。
纳入14名现役精英自然健美运动员（年龄：26±7岁；体重指数：26.9±7.1kg/m²；肌肉量：40.4±7.1kg；体脂百分比：15.5±4.4%）作为参与者。在确认尿液比重后，参与者采用随机、双盲、交叉设计，咀嚼含3mg/kg咖啡因的含咖啡因口香糖（CAF试验）或不含咖啡因的安慰剂口香糖（PL试验）10分钟。休息15分钟后，参与者通过在阻力水平可调的自行车上骑行进行减重过程。骑行持续进行，直到参与者达到脱水状态，体重减轻初始体重的2%。记录从运动到脱水完成的时间、心率、心率变异性（HRV）、排尿量和能量消耗。
在脱水运动期间，CAF试验中的排尿量（P=0.040）和交感神经激活显著高于PL试验（P<0.05）。CAF试验中的脱水时间（P=0.024）和运动期间的主观用力程度（RPE）评分显著低于PL试验。两项试验在脱水运动期间的心率和能量消耗无显著差异（P<0.05）。
本研究发现，咀嚼含咖啡因口香糖可增加健美运动员的交感神经活动并加速脱水。
本研究已在ClinicalTrials.gov注册（日期：2024年8月4日；标识符“NCT06431035”；https://register.CLINICALTRIALS.gov ）。
