尽管现在推荐为时过早，一项新的研究建议使用咖啡因能够减少困扰训练者的运动后疼痛。在发表于疼痛杂志2月刊上的一项研究中，乔治亚大学一个研究小组在一个小样本的自愿受试者中发现适量咖啡因（大致相当于2杯咖啡）能将运动后肌肉疼痛减少48%。
主要作者Victor Maridakis是乔治亚大学教育学院人体运动学系的研究员，他说：这个发现可能与最近锻炼过的人特别有关，因为他们经历了明显的疼痛。他提到：如果你能用咖啡因减少疼痛，那就很容易从第一周的训练过渡的更长时间的训练计划。Maridakis和他的同事研究了女子学院的九个学生，她们没有常规使用咖啡因也没有进行常阻力训练。在能够引起中等度肌痛的训练后一两天，受试者分别服用咖啡因或者安慰剂并进行不同的股四头肌训练。一种运动达到最大耐受量，另一种达到次耐受量。在最大耐受量测试前一小时服用咖啡因组相比安慰剂组疼痛减少了48%，在次耐受量时咖啡因组比对照组疼痛减少26%。
咖啡因很早就被用来增加警觉和耐力，乔治亚大学Patrick O'Connor教授领衔的2003年的一项研究发现：咖啡因能减少中等强度骑车引起的大腿肌痛。先后随同Kevin McCully和Gary Dudley教授合作进行目前研究的O'Connor解释咖啡因可能通过阻断体内某种腺苷（一种炎症反应产生的化学物质）受体起作用。尽管研究得出了阳性结果，但研究人员称：还存在一些不确定因素。首先，可能这个结果不适用于经常摄入咖啡因者，因为可能他们对咖啡因的效果不敏感。研究者选择研究女性，至少在女性中得到了明确的结果。但是男性可能对咖啡因有不同的反应。只有九个受试者的小样本量意味着这个研究还需经过大样本的研究来验证。
O'Connor说虽然还有这些不足，但是相比常规药物而言，在缓解运动后肌痛方面，咖啡因显示出更加有效的作用。之前的研究已经发现：止痛剂甲氧萘丙酸（萘普生钠的有效成分）能将疼痛减轻30%，阿司匹林达25%，而布洛芬的效果不肯定。
研究者还是建议人们练习前谨慎使用咖啡因，过多的咖啡因能引起诸如神经过敏、心悸和睡眠障碍等副作用。Maridakis说：它能减少疼痛，但你必须有判断的应用而且不能超量。
Caffeine Cuts Post-Workout Pain By Nearly 50 Percent, UGA Study Finds
Main Category: Sports Medicine / Fitness News
Article Date: 11 Jan 2007 - 12:00 PST
Although it's too soon to recommend dropping by Starbucks before hitting the gym, a new study suggests that caffeine can help reduce the post-workout soreness that discourages some people from exercising.
In a study to be published in the February issue of The Journal of Pain, a team of University of Georgia researchers finds that moderate doses of caffeine, roughly equivalent to two cups of coffee, cut post-workout muscle pain by up to 48 percent in a small sample of volunteers.
Lead author Victor Maridakis, a researcher in the department of kinesiology at the UGA College of Education, said the findings may be particularly relevant to people new to exercise, since they tend to experience the most soreness.
"If you can use caffeine to reduce the pain, it may make it easier to transition from that first week into a much longer exercise program," he said.
Maridakis and his colleagues studied nine female college students who were not regular caffeine users and did not engage in regular resistance training. One and two days after an exercise session that caused moderate muscle soreness, the volunteers took either caffeine or a placebo and performed two different quadriceps (thigh) exercises, one designed to produce a maximal force, the other designed to generate a sub-maximal force. Those that consumed caffeine one-hour before the maximum force test had a 48 percent reduction in pain compared to the placebo group, while those that took caffeine before the sub-maximal test reported a 26 percent reduction in pain.
Caffeine has long been known to increase alertness and endurance, and a 2003 study led by UGA professor Patrick O'Connor found that caffeine reduces thigh pain during moderate-intensity cycling. O'Connor, who along with professors Kevin McCully and the late Gary Dudley co-authored the current study, explained that caffeine likely works by blocking the body's receptors for adenosine, a chemical released in response to inflammation.
Despite the positive findings in the study, the researchers say there are some caveats. First, the results may not be applicable to regular caffeine users, since they may be less sensitive to caffeine's effect. The researchers chose to study women to get a definitive answer in at least one sex, but men may respond differently to caffeine. And the small sample size of nine volunteers means that the study will have to be replicated with a larger study.
O'Connor said that despite these limitations, caffeine appears to be more effective in relieving post-workout muscle pain than several commonly used drugs. Previous studies have found that the pain reliever naproxen (the active ingredient in Aleve) produced a 30 percent reduction in soreness. Aspirin produced a 25 percent reduction, and ibuprofen has produced inconsistent results.
"A lot of times what people use for muscle pain is aspirin or ibuprofen, but caffeine seems to work better than those drugs, at least among women whose daily caffeine consumption is low," O'Connor said.
Still, the researchers recommend that people use caution when using caffeine before a workout. For some people, too much caffeine can produce side effects such as jitteriness, heart palpitations and sleep disturbances.
"It can reduce pain," Maridakis said, "but you have to apply some common sense and not go overboard."
http://www.medicalnewstoday.com/medicalnews.php?newsid=60491
编辑：蓝色幻想
