Alves M N, Ferrari-Auarek W M, Pinto K M, Sá K R, Viveiros J P, Pereira H A, Ribeiro A M, Rodrigues L O
Departamento de Educação Física, Escola de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
Braz J Med Biol Res. 1995 Jun;28(6):705-9.
Stimulant properties during exercise have been attributed to caffeine (CAF) and tryptophan (Trp). The purpose of the present study was to investigate the effects of CAF and Trp ingestion on rectal temperature (Tre), total exercise time (TET), oxygen consumption (VO2), carbon dioxide production (VCO2), pulmonary ventilation (VE), heart rate (HR) and rate of perceived exertion (RPE) during exercise on a cycle ergometer at 80% of maximal work load, in eight healthy male volunteers. Each subject abstained from caffeine for 48 h and from animal-derived foods for 36 h before each experiment. Aerobic capacity was determined on the first day. In consecutive trials, conducted in a double-blind, randomized, crossed-over manner, each subject received capsules containing CAF (10 mg/kg), Trp (1.2 g), a combination of the two (CAF+Trp), and lactose (PLA), 1 h before exercise. Plasma CAF concentration (PC) was measured by high performance liquid chromatography (HPLC), before (basal concentration) and 1 and 2 h after ingestion of the capsules. At both times after CAF or CAF+Trp ingestion, the PC was elevated compared with the basal concentration (P < 0.05). During exercise, significant increases occurred with time in Tre, TET, VO2, VCO2, VE, HR and RPE (P < 0.01) while no significant difference was observed when CAF or CAF+Trp were compared with control values. Under the conditions of this study, CAF and/or Trp did not affect the physiological parameters measured before, during or after exercise at 80% of maximal work load.
运动期间的兴奋特性一直被归因于咖啡因（CAF）和色氨酸（Trp）。本研究的目的是调查在八名健康男性志愿者以最大工作负荷的80%在自行车测力计上进行运动期间，摄入CAF和Trp对直肠温度（Tre）、总运动时间（TET）、耗氧量（VO2）、二氧化碳产生量（VCO2）、肺通气量（VE）、心率（HR）和主观用力程度（RPE）的影响。每次实验前，每位受试者需48小时不摄入咖啡因，36小时不食用动物源性食物。第一天测定有氧能力。在随后以双盲、随机、交叉方式进行的试验中，每位受试者在运动前1小时服用含有CAF（10毫克/千克）、Trp（1.2克）、两者组合（CAF+Trp）和乳糖（PLA）的胶囊。在摄入胶囊前（基础浓度）以及摄入后1小时和2小时，通过高效液相色谱法（HPLC）测量血浆CAF浓度（PC）。在摄入CAF或CAF+Trp后的两个时间点，PC均高于基础浓度（P<0.05）。运动期间，Tre、TET、VO2、VCO2、VE、HR和RPE随时间显著增加（P<0.01），而将CAF或CAF+Trp与对照值进行比较时未观察到显著差异。在本研究条件下，CAF和/或Trp在最大工作负荷的80%的运动前、运动期间或运动后均不影响所测量的生理参数。
