Human Performance Laboratory, University of Connecticut, Storrs, CT 06269, USA.
Physiol Behav. 2011 Mar 1;102(3-4):429-35. doi: 10.1016/j.physbeh.2010.12.005. Epub 2010 Dec 14.
Caffeine (CAF) ingestion may enhance endurance exercise by lowering perceived exertion (RPE) and muscle pain. However, exercise in the heat may be detrimental to performance by increasing RPE and pain. The purpose of this study was to examine if caffeine affects pain and related perceptual responses differently in cool and hot ambient conditions. Eleven male cyclists (mean ± SD; age, 25 ± 6 years; mass, 72.6 ± 8.1 kg; VO(2max), 58.7 ± 2.9 ml kg(-1) min(-1)) completed four trials in a randomized, double blind design. While remaining euhydrated, subjects cycled for 90 min at 65 ± 7% VO(2max) followed by a 15-min performance trial. Subjects ingested 3 mg kg(-1) of encapsulated caffeine (CAF) or placebo (PLA) 60 min before and 45 after beginning exercise in 12°C and 33°C (i.e., 12-CAF, 33-CAF, 12-PLA, and 33-PLA trials). Central, local, and overall perceived exertion (C-, L-, and O-RPE) and pain were measured throughout exercise. Throughout submaximal exercise C-, L-, and O-RPE were significantly greater in 33°C (P<0.05) but were not affected by CAF (P>0.05). Using area-under-the-curve analysis, pain in 33-PLA was increased by 74% vs 12-PLA (P<0.05). CAF did not reduce pain in 12°C (P=0.542), but in 33°C, CAF reduced pain by 27% (P=0.032). Despite this apparent advantage, CAF improved performance independent of ambient temperature (i.e., non-significant interaction; P=0.662). This study found that, although caffeine improves exercise capacity, its effect on leg muscle pain is dependent on ambient temperature. Although exercise in the heat increases muscle pain compared to a cooler environment, caffeine reduces this pain.
咖啡因（CAF）的摄入可以通过降低感知的努力（RPE）和肌肉疼痛来增强耐力运动。然而，在高温下运动可能会通过增加 RPE 和疼痛而对表现产生不利影响。本研究的目的是检查咖啡因是否在凉爽和炎热的环境条件下对疼痛和相关的感知反应产生不同的影响。11 名男性自行车手（平均±SD；年龄，25±6 岁；体重，72.6±8.1kg；最大摄氧量（VO2max），58.7±2.9mlkg-1min-1）以随机、双盲设计完成了四项试验。在保持水合状态的情况下，受试者以 65±7%VO2max 的强度骑行 90 分钟，然后进行 15 分钟的运动表现试验。在 12°C 和 33°C 时，受试者在运动前 60 分钟和运动后 45 分钟内分别摄入 3mgkg-1 的封装咖啡因（CAF）或安慰剂（PLA）（即 12-CAF、33-CAF、12-PLA 和 33-PLA 试验）。在整个运动过程中测量中央、局部和整体感知的努力（C-、L-和 O-RPE）和疼痛。在亚最大运动期间，33°C 时 C-、L-和 O-RPE 显著更高（P<0.05），但不受 CAF 的影响（P>0.05）。通过曲线下面积分析，33-PLA 的疼痛增加了 74%，而 12-PLA 增加了 74%（P<0.05）。CAF 并未降低 12°C 时的疼痛（P=0.542），但在 33°C 时，CAF 降低了 27%的疼痛（P=0.032）。尽管存在这种明显的优势，但 CAF 改善了运动能力，而不受环境温度的影响（即，无显著相互作用；P=0.662）。本研究发现，尽管咖啡因提高了运动能力，但它对腿部肌肉疼痛的影响取决于环境温度。尽管在高温下运动比在较凉爽的环境中增加肌肉疼痛，但咖啡因可减轻这种疼痛。
