月经周期对女运动员耐力运动时物质代谢及激素变化的影响

    付德荣 刘承宜 孙小华

    摘要:综述了月经周期中雌、孕激素水平波动对耐力运动时物质代谢及相关激素的影响作用。前人的研究表明,中低强度运动时雌激素可增加脂类氧化,减少糖的利用,起着碳水化合物节省化效应。孕激素在雌激素作用的基础上提高脂类氧化,增加有氧运动能力。在雌、孕激素较高的黄体期进行有氧运动,机体氧化脂类能力高于卵泡期,利用碳水化合物能力低于卵泡期。月经周期对胰岛素、儿茶酚胺类激素、生长激素及糖皮质激素的基础值及运动诱导的反应值没有明显影响作用。因此,运动训练过程中应考虑月经周期时相对物质代谢的影响作用以期充分地发挥女性运动员的生理潜能。

    关键词:运动生理学;月经周期;雌激素;孕激素;物质代谢;耐力运动;综述

    中图分类号:G804.7文献标识码:A文章编号:1006-7116(2009)01-0100-06

    Effects of the menstrual cycle on substance metabolism and female athletes

    hormone changes of during an endurance exercise

    FU De-rong1,LIU Cheng-yi1,SUN Xiao-hua2

    (1.Laboratory of Laser Sports Medicine,South China Normal University,Guangzhou 510006,China;

    2.Guangdong Vocational Institute of Sports,Guangzhou 510663,China)

    Abstract: The authors gave an overview of the effects of the fluctuation of estrogen and progesterone levels in the menstrual cycle on substance metabolism and related hormones during an endurance exercise. Previous researches indicated that during a medium or low intensity exercise estrogen can increase lipid oxidation and reduce glucose utilization, achieving the effect of carbohydrate saving. On the basis of estrogen functions, progesterone promotes lipid oxidation and enhances the aerobic exercise capacity. During an aerobic exercise done in the corpus luteum period with a relatively high level of estrogen and progesterone, the lipid oxidation capacity of the body is higher than the same in the ovarian follicle period, while the carbohydrate utilization capacity of the body is lower than the same in the ovarian follicle period. The menstrual cycle has no significant effect on the basic values and sport induced reaction values of insulin, catecholamine hormone, growth hormone and glucocorticoid. Therefore, during sports training the effects of the menstrual cycle on substance metabolism should be considered in order to fully exert physiological potentials of female athletes.

    Key words: sports physiology;menstrual cycle;estrogen;progesterone;substance metabolism;endurance exercise;overview

    月经周期是下丘脑-垂体-卵巢轴相互协调及性器官靶组织对性激素反映的结果。随着卵泡发育成熟及排卵,体内雌、孕激素水平呈现明显的周期性波动,子宫内膜随之发生周期性的剥脱和出血。雌、孕激素这种周期性的变化规律不仅调节着女性的生殖功能,还与机体的物质代谢及运动能力有着密切的关系。

    1雌、孕激素对物质代谢的影响

    耐力性运动中,女性利用脂肪供能比例明显高于男子,而碳水化合物(carbohydrate,CHO)氧化(CHO oxidation,CHOox)能力弱于男性[1],呈现物质代谢的性别差异与女性体内较高的雌激素水平有关[2-3]。成年男性补充雌激素后可降低运动时呼吸交换率(respiratory exchange ratio,RER),在65%最大摄氧量(VO2max)强度运动时减少CHOox,提高脂类利用,提高脂肪与CHOox比达31%~75%[4]。闭经女性补充雌激素后,安静时游离脂肪酸(free fatty acids,FFA)明显升高,以65% VO2max跑台运动90 min后再以85% VO2max运动至力竭,与安慰剂组比较,雌激素补充组运动过程中糖显现率(rate of appearance,Ra)及糖消率(rate of disappearance,Rd)均明显下降[5]。人为控制正常女性体内性激素自发性周期变化而给与外源的雌激素时,60% VO2max强度踏车运动60 min,RER明显降低、糖Ra和Rd降低、肌糖原利用估计值(estimated muscle glycogen utilization,EMGU)下降、血浆FFA的浓度升高,CHOox呈现节省化,而脂类利用增加[3]。雌激素补充同样可降低男性耐力运动时机体糖Ra和Rd[4],从而调节运动时血糖平衡。

    动物实验显示相似结果。雄性大鼠注射雌激素可明显增加其运动肌对脂类的利用[6],在2 h的次最大强度跑台运动中,与对照组比较,肝糖原、肌糖原下降的速度显著减慢[7],糖的消耗明显减少,脂肪酸氧化增加,血乳酸浓度降低,运动成绩提高[8]。卵巢切除的大鼠骨骼肌结合胰岛素能力下降,骨骼肌减少了对胰岛素诱导的2-脱氧-D-葡萄糖(insulin-stimulated 2-deoxy-D-glucose,2-DOG)的摄取,减少了肌糖原的合成[9-10],糖异生增强,肝、心肌、骨骼肌等各组织中糖原的含量减少,血糖升高[11]。雌激素补充可恢复骨骼肌结合胰岛素的能力,恢复对2-DOG的正常摄取[9-10],降低糖异生,增加肌糖原及肝糖原的沉积[11],减少运动时对糖的氧化利用,出现碳水化合物的节省化效应[12]。

    雌激素增加脂肪氧化,减少运动时CHO消耗,与其调节物质代谢过程中相关酶活性以及有关激素的敏感性有关。实验证明,雌激素可提高运动肌中脂蛋白脂肪酶(lipoprotein lipase,LPL)活性,升高股红肌与脂肪组织中LPL活性比及心肌与脂肪组织中LPL活性比,促进脂肪酸向运动肌的流向[6];提高肉碱棕榈酰基转移酶活性,并可逆转大鼠因卵巢切除所致的β-羟脂酰辅酶A脱氢酶(beta-Hydroxyacyl-CoA dehydrogenase β-HAD)活性的降低,使之恢复正常水平[13];增加胰岛素的敏感性及与靶细胞结合的能力[10];调节糖原合成酶及柠檬酸合成酶的活性[14];减少中等强度运动时肾上腺素的分泌量[5];提高白色脂肪细胞中腺苷酸环化酶活性,增加肾上腺素的脂解作用[15];减少运动过程中EMGU及糖Rd[3]等。雌激素通过上述多种方式减少糖利用,增加脂肪氧化供能比。

    孕激素调节物质代谢的作用没有雌激素明显。单独使用孕激素对卵巢切除的大鼠糖代谢动力学参数的恢复影响不明显[9]。与雌激素联合应用时,在雌激素作用基础上促进脂类氧化加强[16-18],并增加有氧运动能力[18]。给健康女性口服避孕药并进行递增负荷实验,随着运动强度的增加,高孕激素组(35 μg ethinyl estradiol和1 000 μg norethisterone。high progestin,高Ph)峰值摄氧量(peak oxygen uptake VO2peak)升高的幅度大于低孕激素组(35 μg ethinyl estradiol和500 μg norethisterone。low progestin,低PL),RER低于低P组,峰值功力输出(peak power output,Wlpeak)有升高趋势,运动至疲劳的时间延长。在以75% VO2peak强度持续运动20 min时,高Ph组氧脉搏增加,RER降低,脂类的氧化增强,运动至力竭的时间相对延长,峰值摄氧量有上升的趋势,总做功量增加,但功力输出、心率、峰值乳酸浓度不受孕激素浓度的影响[18]。孕激素对物质代谢的作用可能与其降低己糖激酶的活性[19]、减弱磷酸戊糖途径代谢[20]、降低脂肪细胞对胰岛素的敏感性[21]、降低脂肪酸的合成[22]等多种调节途径有关。

    2月经时相对物质代谢的影响

    月经周期的不同时相中,雌、孕激素水平会有明显变化。黄体期雌激素的水平比卵泡期升高3倍左右,孕激素升高达20倍左右(血清雌激素:卵泡早期0.18~0.22 nmol/L,黄体期0.55~0.7 nmol/L;血清孕激素:卵泡早期<3 nmol/L,黄体期32~64 nmol/L)[23]。这种变化对运动时物质代谢会有一定的影响,主要体现在对糖的Ra、Rd、糖代谢清除率(glucose metabolic clearance rate,MCR)[17,24-25]及脂类的Ra和Rd以及RER的调节上[17]。

    2.1对碳水化合物代谢的影响

    CHO在运动中的供能比例随着运动强度的增大而增加[26-27]。当运动强度达65% VO2max以上时,CHOox迅速上升,脂类氧化明显降低[26],强度达(89±3)%VO2max,((92±1)%HRmax)以上时,脂类氧化供能比几乎可忽略不计[28]。在接近VO2max强度运动时,肌糖原、肝糖原是能量的主要来源[29]。

    安静时,月经周期时相对糖代谢动力学、血乳酸、RER影响不明显[17,25,30-31]。运动状态下,月经周期对物质代谢的影响作用与运动强度、运动水平及运动持续的时间等有关。以35% VO2max及60% VO2max强度跑台运动30 min,正常月经周期的普通女性黄体中期氧化利用CHO的比例明显低于卵泡中期,当运动强度达75% VO2max时,CHOox利用在卵泡、黄体两期中没有差异[16]。有运动习惯的女性以70%乳酸阈(lactate threshold,LT)强度功率自行车运动25 min,总CHOox、血乳酸浓度、RER、糖Ra或Rd在卵泡期和黄体期中没有差异,但在紧接其后以90% LT强度继续运动25 min时,黄体期总CHOox比卵泡期低13%,糖Ra低于卵泡期14%,Rd低于卵泡期15%,血乳酸、RER亦明显低于卵泡期。血糖浓度在安静及70% LT或90% LT强度运动时,黄体期的值均高于卵泡期[17]。Devries等[24]的实验也显示休闲运动青年女性在65% VO2peak强度功率车运动90 min时,黄体期(月经周期的(20±1) d)Ra、Rd和MCR值均低于卵泡期(月经周期的(9±1)d),黄体期骨骼肌利用前糖原、大糖原、总糖原比卵泡期分别降低30%、16%及24%;血糖及肌糖原在总CHOox中的贡献率,卵泡期为29%和71%,黄体期为32%和68%,差异不明显。但也有实验显示中等强度运动时月经周期时相对CHO代谢没有明显影响作用[25]。

    如果在运动的前中后过程中合理补充糖饮料,月经周期时相对糖代谢的影响作用就会减弱或消失。Campbell等[32]对中等程度训练的8名月经周期正常的女性进行70% VO2peak强度自行车运动2 h,紧接着再进行4 kJ/kg的最快速度定量计时测试,结果显示非补糖组卵泡期CHOox百分比((80.1±1.2)%)明显高于黄体期((77.0±1.0)%)(P<0.05),糖Ra、Rd,MCR及肝葡萄糖生成(hepatic glucose production,HGP)亦明显高于黄体期,卵泡期的成绩比黄体期提高13%。在补糖组中糖代谢动力学的差异基本消失,总CHOox百分比、糖Ra、Rd,MCR的值在卵泡、黄体两期中没有明显变化,且补糖组中总CHOox百分比、血糖以及糖Ra、Rd均高于非补糖组的任何时期,HGP低于非补糖组任何时期,但血LT、MCR在补糖组与非补糖组没有明显不同。补糖组的运动成绩与非补糖组比较卵泡期及黄体期分别提高了19%及26%。

    2.2对脂类代谢的影响

    脂肪的氧化利用是中低强度运动时的主要能量来源[26,33],耐力训练可提高机体利用脂肪的能力[34]。中等程度训练者最大氧化脂肪的运动强度范围为(55±3)%~(72±4)% VO2max[28],而普通人群为(48.3±0.9)% VO2max[35]。运动方式对脂类的氧化率亦有影响作用,同等强度运动时,跑步运动者脂类的氧化利用率高于自行车运动者[36]。

    安静状态下月经周期时相对脂类的代谢没有影响[17,37]。在35% VO2max及60% VO2max强度跑台运动时,正常月经周期的普通女性黄体中期氧化脂肪的能力明显高于卵泡中期,当运动强度达75% VO2max时,这种差异消失[16]。Zderic等[17]对运动习惯的民众进行70% LT强度功率自行车运动25 min,总脂类的氧化在卵泡期和黄体期没有差异,但在紧接其后的90% LT强度运动时,黄体期总脂类的氧化利用高于卵泡期23%。Campbell等[32]实验也显示在70% VO2peak强度运动时,中等程度训练的女性黄体期脂类氧化百分比明显高于卵泡期。运动过程中合理补充糖饮料,可降低月经各期中脂类的氧化百分比,并消除卵泡黄体两期中氧化脂类的差异[32]。但Horton等[38]实验却显示50%VO2max强度90 min功力车运动时,月经时相对脂类的代谢没有明显影响作用。

    月经周期时相对CHO及脂类代谢的影响作用与运动者的运动水平、运动模式、运动强度以及运动时间的选择有关。高水平运动者氧化脂类的能力高于低水平运动者。运动模式不同募集的运动肌群不同,氧化能源有所差异。运动强度与运动时间的安排直接决定了CHO及脂类的功能比例。运动者个体间性激素周期性波动幅度的差异对物质代谢也可能存在着一定影响作用。

    3月经周期对相关激素水平的影响

    体内物质代谢受多种激素的调节,如胰岛素、儿茶酚胺类激素、肾上腺皮质激素以及生长激素等,这些激素的水平变化可直接影响机体的物质代谢及运动能力的发挥。

    实验显示,安静状态下胰岛素浓度在正常月经周期的卵泡期和黄体期中没有明显差异[17,25],但对其敏感性存在不同观点。Diamond[39]和Toth等[40]的实验显示胰岛素敏感性不受月经周期时相的影响,而Valdes[37]和Escalante[41]等的实验表明胰岛素敏感性在黄体期时明显下降(前者P<0.007,后者P<0.001)。运动可提高胰岛素的敏感性[42],降低体内胰岛素的水平[43-44]。月经周期的不同时期运动,对胰岛素浓度的影响各实验结果间存在一定差异。Zderic等[17]报道在月经不同时期以70% LT或90% LT的不同强度运动,胰岛素在运动中的反应水平不受月经周期时相的影响;Horton TJ等[25]实验显示,50% VO2max强度90 min运动时,胰岛素浓度在黄体中期明显高于卵泡早期和卵泡中期(P<0.001),伴有明显的血糖升高的同步变化,尤其在运动的最初45 min内;而Braun等[43]的实验则显示52% VO2peak强度功率车运动15 min时,黄体期胰岛素的值明显低于卵泡期,随运动时间的延长这种差异消失。运动过程中合理补充糖饮料可降低长时间运动引起的血糖及胰岛素水平的下降,延长至疲劳的时间[32,45]。

    运动明显升高儿茶酚胺类激素的水平[25,30,46-47],在接近100% VO2max强度运动时,肾上腺素浓度可升高14倍,去甲肾上腺素可升高18倍[47]。运动水平对其存在影响作用,运动员安静及运动时肾上腺素的浓度均高于非运动员[46]。月经周期时相对儿茶酚胺类激素不产生明显影响[30,48]。Dean[30]的实验显示在卵泡早期、卵泡中期及黄体中期中,肾上腺素的安静值分别为(24±2)、(23±3)、(26±5) pg/mL,去甲肾上腺素的安静值分别为(242±60)、(229±33)、(225±16) pg/mL;在乳酸阈强度运动结束时,肾上腺素的质量浓度分别为(418±110)、(336±70)、(353±51) pg/mL,去肾上腺素的质量浓度分别为(3 800±1 109)、(4 135±1 076)、

    (4 034±961) pg/mL,均没有明显差异。Braun[43]及Botcazou等[48]的实验也同样说明了肾上腺素及去甲肾上腺素的水平变化与月经周期时相没有联系,而与运动强度及运动时间关系密切[25,48]。

    安静时肾上腺皮质激素及促皮质激素(adrenocorticotropic hormone,ACTH)浓度不受月经周期的影响,以70% VO2max运动明显升高该2激素的水平,但在月经周期的不同时相中其对运动刺激的反应相似[49]。Horton等[25]的实验显示可的松的安静值在月经周期的不同阶段水平相似,在50% VO2max强度90 min运动时,可的松水平明显升高,并存在时间效应关系,但这种反应不受月经周期时间差别的影响。Braun[43]、Bailey[45]及Kanaley[50]的实验同样反映出可的松水平在安静时及运动时均不受月经周期时相的影响。运动过程中合理补糖对可的松浓度有影响。在70% VO2max强度运动至疲劳的实验中,运动至60 min时,补糖组可的松浓度大于非补糖组((357±26)、(274±28) nmol/L),但运动至疲劳时,补糖组可的松水平低于非补糖组((486±57)、(625±59) nmol/L)[45]。

    运动明显升高血生长激素(growth hormone GH)水平,其峰值幅度与运动负荷量明显相关[51-53]。年龄、性别及运动水平对GH的浓度有影响作用。优秀女子运动员GH基础值高于优秀男子运动员[52],年轻女性GH对运动刺激的反应释放量高于同龄男子及年长者[51],长期耐力训练可提高GH的敏感性,降低GH的基础值及对运动刺激的反应值[53]。实验显示,月经周期对GH安静值及运动刺激的反应值均无明显影响作用[17,54]。以60% VO2max强度运动90 min时,卵泡早期、卵泡中期及黄体中期的GH反应值分别是(37.5±11.5)、(61.9±11.5)及(48.1±12.8) μg/L,没有明显差异[54]。Zderic等[17]报道GH安静值在卵泡期((1.4±0.03) ng/mL)及黄体期((1.6±0.19) ng/mL)中相似,以70%和90% LT运动后,黄体期GH值(70% LT(11.6±4.2) ng/mL,90% LT(11.1±2.4) ng/mL)稍高于卵泡期(70% LT(8.8±4.3) ng/mL,90% LT(8.5±2.6) ng/mL),但差异无显著性。

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