Haakonssen Eric C, Ross Megan L, Knight Emma J, Cato Louise E, Nana Alisa, Wluka Anita E, Cicuttini Flavia M, Wang Bing H, Jenkins David G, Burke Louise M
Sports Nutrition, Australian Institute of Sport, Belconnen, 2616, Australia; Physiology, Australian Institute of Sport, Belconnen, 2616, Australia; Human Movement Studies, University of Queensland, St Lucia, 4072, Australia.
Sports Nutrition, Australian Institute of Sport, Belconnen, 2616, Australia; Physiology, Australian Institute of Sport, Belconnen, 2616, Australia.
PLoS One. 2015 May 13;10(5):e0123302. doi: 10.1371/journal.pone.0123302. eCollection 2015.
Cycling is recognised as a sport in which there is a high incidence of poor bone health. Sweat calcium losses may contribute to this.
To examine whether a calcium-rich pre-exercise meal attenuates exercise-induced perturbations of bone calcium homeostasis caused by maintenance of sweat calcium losses.
Using a randomized, counterbalanced crossover design, 32 well-trained female cyclists completed two 90 min cycling trials separated by 1 day. Exercise trials were preceded 2 hours by either a calcium-rich (1352 ± 53 mg calcium) dairy based meal (CAL) or a control meal (CON; 46 ± 7 mg calcium). Blood was sampled pre-trial; pre-exercise; and immediately, 40 min, 100 min and 190 min post-exercise. Blood was analysed for ionized calcium and biomarkers of bone resorption (Cross Linked C-Telopeptide of Type I Collagen (CTX-I), Cross Linked C-Telopeptide of Type II Collagen (CTX-II), Parathyroid Hormone (PTH), and bone formation (Procollagen I N-Terminal Propeptide (PINP)) using the established enzyme-linked immunosorbent assay technique.
PTH and CTX-I increased from pre-exercise to post-exercise in both conditions but was attenuated in CAL (p < 0.001). PTH was 1.55 [1.20, 2.01] times lower in CAL immediately post-exercise and 1.45 [1.12, 1.88] times lower at 40 min post-exercise. CTX-I was 1.40 [1.15, 1.70] times lower in CAL at immediately post-exercise, 1.30 [1.07, 1.57] times lower at 40 min post-exercise and 1.22 [1.00, 1.48] times lower at 190 min post-exercise (p < 0.05). There was no significant interaction between pre-exercise meal condition and time point for CTX-II (p = 0.732) or PINP (p = 0.819).
This study showed that a calcium-rich pre-exercise breakfast meal containing ~1350 mg of calcium consumed ~90 min before a prolonged and high intensity bout of stationary cycling attenuates the exercise induced rise in markers of bone resorption--PTH and CTX-I.
Australian New Zealand Clinical Trials Registry ACTRN12614000675628.
骑行被认为是一项骨骼健康状况不佳发生率较高的运动。汗液中钙的流失可能是原因之一。
研究富含钙的运动前餐是否能减轻因维持汗液钙流失而导致的运动引起的骨钙稳态扰动。
采用随机、平衡交叉设计，32名训练有素的女性自行车运动员完成了两次90分钟的骑行试验，中间间隔1天。在运动试验前2小时，运动员分别食用富含钙（1352±53毫克钙）的乳制品餐（CAL）或对照餐（CON；46±7毫克钙）。在试验前、运动前、运动后即刻、40分钟、100分钟和190分钟采集血液样本。使用既定的酶联免疫吸附测定技术分析血液中的离子钙以及骨吸收生物标志物（I型胶原交联C末端肽（CTX-I）、II型胶原交联C末端肽（CTX-II）、甲状旁腺激素（PTH））和骨形成标志物（I型前胶原N端前肽（PINP））。
在两种情况下，PTH和CTX-I从运动前到运动后均升高，但在CAL组中升高幅度减弱（p<0.001）。运动后即刻，CAL组的PTH比对照组低1.55[1.20,2.01]倍，运动后40分钟低1.45[1.12,1.88]倍。运动后即刻，CAL组的CTX-I比对照组低1.40[1.15,1.70]倍，运动后40分钟低1.30[1.07,1.57]倍，运动后190分钟低1.22[1.00,1.48]倍（p<0.05）。运动前餐条件与CTX-II（p = 0.732）或PINP（p = 0.819）的时间点之间没有显著交互作用。
本研究表明，在长时间高强度的室内骑行前约90分钟食用含约1350毫克钙的富含钙的运动前早餐餐可减轻运动引起的骨吸收标志物——PTH和CTX-I的升高。
澳大利亚新西兰临床试验注册中心ACTRN12614000675628。
