Stevenson Jada L, Krishnan Sridevi, Inigo Melissa M, Stamatikos Alexis D, Gonzales Joaquin U, Cooper Jamie A
a Department of Nutritional Sciences , Texas Tech University , Lubbock , Texas , USA.
b Department of Exercise and Sports Sciences , Texas Tech University , Lubbock , Texas , USA.
J Diet Suppl. 2016;13(3):324-38. doi: 10.3109/19390211.2015.1036189. Epub 2015 Aug 28.
To determine if an echinacea-based dietary supplement (EBS) provided at two different doses (a regular dose (RD), 8,000 mg/day, vs. a double dose (DD), 16,000 mg/day) would increase erythropoietin (EPO) and other blood markers involved in improving aerobic capacity and maximal oxygen consumption (VO2max) in endurance-trained men. Secondly, to determine if any sex differences exist between male and female endurance-trained athletes.
Forty-five endurance athletes completed three visits during a 35-day intervention. Participants were randomized into placebo (PLA; n = 8 men, n = 7 women), RD of EBS (n = 7 men, n = 8 women), or DD of EBS (n = 15 men) for the 35-day intervention period. At baseline, weight, body composition, and VO2max were measured. Blood was drawn to measure EPO, ferritin, red blood cells, white blood cells, hemoglobin, and hematocrit. At the mid-intervention visit, blood was collected. At the post-intervention visit, all measurements from the baseline visit were obtained once again.
There was a significant increase in VO2max for endurance-trained men in PLA (increase of 2.8 ± 1.5 ml kg(-1) min(-1), p = .01) and RD of EBS (increase of 2.6 ± 1.8 ml kg(-1) min(-1), p = .04), but not in DD of EBS (p = .96). Importantly, there was no difference in the change in VO2max between PLA and RD of EBS. For endurance-trained women, VO2max did not change in either treatment (PLA: -0.7 ± 1.7 ml kg(-1) min(-1), p = .31; RD of EBS: -0.2 ± 2.4 ml kg(-1) min(-1), p = .80). There were no significant changes in any blood parameter across visits for any treatment group.
This EBS should not be recommended as a means to improve performance in endurance athletes.
确定两种不同剂量（常规剂量（RD），8000毫克/天，与双倍剂量（DD），16000毫克/天）的紫锥菊属膳食补充剂（EBS）是否会增加耐力训练男性的促红细胞生成素（EPO）以及其他与提高有氧能力和最大摄氧量（VO2max）相关的血液指标。其次，确定耐力训练的男性和女性运动员之间是否存在性别差异。
45名耐力运动员在35天的干预期间完成了三次访视。在35天的干预期内，参与者被随机分为安慰剂组（PLA；8名男性，7名女性）、EBS常规剂量组（7名男性，8名女性）或EBS双倍剂量组（15名男性）。在基线时，测量体重、身体成分和VO2max。采集血液以测量EPO、铁蛋白、红细胞、白细胞、血红蛋白和血细胞比容。在干预中期访视时采集血液。在干预后访视时，再次获取基线访视时的所有测量值。
PLA组（增加2.8±1.5毫升·千克⁻¹·分钟⁻¹，p = 0.01）和EBS常规剂量组（增加2.6±1.8毫升·千克⁻¹·分钟⁻¹，p = 0.04）中耐力训练男性的VO2max有显著增加，但EBS双倍剂量组没有（p = 0.96）。重要的是，PLA组和EBS常规剂量组之间VO2max的变化没有差异。对于耐力训练的女性，两种治疗中VO2max均未改变（PLA组：-0.7±1.7毫升·千克⁻¹·分钟⁻¹，p = 0.31；EBS常规剂量组：-0.2±2.4毫升·千克⁻¹·分钟⁻¹，p = 0.80）。任何治疗组在各次访视期间的任何血液参数均无显著变化。
不应推荐使用这种EBS来提高耐力运动员的成绩。
