间接判定运动员滥用人生长激素的指标 的可行性研究Ⅰ

实验研究(1)的实验对象为体育师范学院运动系篮球专业男学生10名。竞技体校少年篮球男运动员8名。受试者采用递增负荷方式,在JAEGER跑台上跑至力竭。实验结果表明短时间力竭运动后即刻、运动后30 min,两组运动员血清GH浓度显著高于安静值;运动后60 min与运动前相比较,血清GH浓度无显著性差异,呈恢复趋势。血清GH浓度具有明显的个体差异性。短时间力竭运动后60 min与运动前相比较,运动系学生血清IGF-Ⅰ和IGF-Ⅱ浓度无显著性差异;而竞技体校少年男子篮球运动员力竭运动后60 min与运动前相比较,血清 IGF-Ⅰ浓度显著高于安静值。短时间力竭运动后60 min与运动前相比较,运动系学生血清IGFBP-3浓度显著低于运动前安静值。短时间力竭运动前、后各组间比较,IGF-Ⅰ/IGF-Ⅱ、IGF-Ⅰ/IGFBP-3比值均无显著性差异。血清IGF-Ⅰ浓度与IGF-Ⅰ/IGF-Ⅱ、IGF-Ⅰ/IGFBP-3比值呈高度显著性正相关。     

间接判定运动员滥用人生长激素的指标的可行性研究Ⅰ-短时间力竭运动对血清生长激素、胰岛素样生长因子-Ⅰ、Ⅱ、结合蛋白-3的影响

实验研究(1)的实验对象为体育师范学院运动系篮球专业男学生10名。竞技体校少年篮球男运动员 8名。受试者采用递增负荷方式,在 JAEGER 跑台上跑至力竭。实验结果表明:短时间力竭运动后即刻、运动后 30 min,两组运动员血清 GH浓度显著高于安静值;运动后 60 min与运动前相比较,血清 GH浓度无显著性差异,呈恢复趋势。血清 GH浓度具有明显的个体差异性。短时间力竭运动后 60 min与运动前相比较,运动系学生血清 IGF-Ⅰ和 IGF-Ⅱ浓度无显著性差异;而竞技体校少年男子篮球运动员力竭运动后 60 min与运动前相比较,血清 IGF-Ⅰ浓度显著高于安静值。短时间力竭运动后 60 min与运动前相比较,运动系学生血清 IGFBP-3浓度显著低于运动前安静值。短时间力竭运动前、后各组间比较,IGF-Ⅰ/IGF-Ⅱ、IGF-Ⅰ/IGFBP-3 比值均无显著性差异。血清 IGF-Ⅰ浓度与 IGF-Ⅰ/IGF-Ⅱ、IGF-Ⅰ/IGFBP-3 比值呈高度显著性正相关。     

力竭运动对血清高亲和力生长激素结合蛋白(GHBP)及胰岛素样生长因子(IGF-I)水平影响的研究

为了解运动对血清IGF I和GHBP水平的影响 ,测定了天津体育学院中长跑专项学生 (男 10人 ,年龄 2 0 .0 0± 1.4 1)安静时和短时间递增负荷力竭运动后即刻IGF I和GHBP的浓度 ,并进一步探讨运动所引起的GH IGF轴的自身调节和作用机制     

大鼠运动性疲劳形成和恢复过程ECoG的动态研究

目的:记录并观察大鼠在一次力竭运动过程及恢复期皮层运动区皮层脑电(Electro-corticogram,ECoG)的变化特征,揭示运动性疲劳形成的中枢机制。方法:通过神经电生理学皮层脑电记录方法,记录大鼠在一次性力竭跑台运动过程中及恢复期皮层运动区的ECoG,动态分析运动性疲劳形成和恢复过程中ECoG频率谱、功率谱的变化特征。结果:大鼠在一次性运动疲劳的形成和恢复过程中ECoG特征会发生显著变化,运动状态下ECoG功率谱总功率显著高于安静状态(P<0.05),在6～9Hz频段出现密集的高能量分布;大鼠疲劳状态下运动ECoG功率谱频率分配与非疲劳状态下运动具有显著性差异(P<0.05),表现为δ波比例显著增加,而α波比例显著下降(P<0.05)。力竭即刻频率分配与运动前安静状态差异显著,表现为δ波比例显著增加,θ波比例显著下降(P<0.05),但在30min恢复期后,频率分配恢复至运动前的状态;在力竭运动过程中大鼠ECoG功率谱重心频率逐渐向低频迁移,在力竭前10min显著低于运动前水平(P<0.05),当运动停止后,重心频率即向高频迁移,30min即恢复至运动前水平。结论:运动性中枢疲劳的形成是一个连续累积的过程,大鼠ECoG在运动性疲劳的形成和发展过程均伴随着δ节律比例的显著增加,提示,慢波δ节律可能是运动性疲劳的重要中枢机制之一。同时,运动疲劳所导致的ECoG变化恢复非常迅速,运动停止后短时间内(30min)即能得到有效的恢复。     

抗阻训练结合电刺激后血浆相关激素水平动态变化分析

目的:探讨抗阻训练结合电刺激增加肌肉力量及含量的相关生物学机制,为抗阻训练提供科学依据。方法:16名健康男大学生随机分为常规抗阻训练组(CREG,n=8),抗阻训练结合电刺激组(HYBG,n=8),所有受试者均完成10组每组包括10次膝关节屈伸的练习,组间间歇时间为60秒,负荷约为65%IRM。分别在运动前、运动后即刻、15 min、30 min、60 min、120 min、24 h时取静脉血,测定血浆GH、IGF-1、NE及LA的浓度。结果:与CREG比较,HY-BG受试者血浆GH水平在训练后即刻至60min显著高于CREG(P<0.01,P<0.05,P<0.05,P<0.05);HYBG受试者血乳酸水平从训练后15 min至30 min显著高于CREG(P<0.05,P<0.05);而血浆IGF-1水平与NE水平的变化趋势,HYBG和CREG比较没有显著差异。结论:抗阻训练结合电刺激对GH和LA的影响比单纯抗阻训练更明显,且不会诱导较强的交感神经活动。这种训练手段提高肌肉力量及含量可能主要是通过提高GH分泌水平实现的。     

纹状体A_(2A)R/D_2DR表达及DARPP-32磷酸化在运动疲劳调控中的作用

目的通过观察跑台运动大鼠力竭前后纹状体腺苷A2A受体/多巴胺D2受体(A2AR/D2DR)表达、磷蛋白DARPP-32表达及其磷酸化,探讨A2AR/D2DR通过纹状体-苍白球通路对运动疲劳调控的可能机制,为寻求新的抗疲劳药物及手段提供理论与实验依据。方法实验选用8周龄雄性健康Wistar大鼠30只,随机分为安静对照组(CG)、力竭即刻组(EG)和力竭后恢复90 min(RG)组,每组10只,建立一次性力竭运动疲劳模型。采用免疫荧光双标技术,观察大鼠安静状态、力竭即刻及恢复90 min时纹状体A2AR和D2DR表达的变化;采用免疫荧光和免疫印迹技术,观察大鼠在安静状态、力竭即刻及恢复90 min时纹状体苍白球神经元(D2-MSNs)内DARPP-32表达及磷酸化水平的变化特征。结果大鼠跑台运动至力竭时纹状体A2AR阳性细胞个数显著增高(P<0.01),D2DR阳性细胞个数显著下降(P<0.01),且A2AR和D2DR共表达于D2-MSNs的胞膜上;恢复90 min时A2AR阳性细胞依然显著高于安静状态(P<0.05),D2DR依然低于安静状态(P<0.05);相比安静状态,力竭运动即刻Thr34-DARPP-32磷酸化增加(P<0.01),恢复90 min时表达显著下降(P<0.05),p-Thr34-DARPP-32/DARPP-32比值增加(P<0.01),恢复90 min后有所下降,但没有显著性差异。结论 A2AR和D2DR共同参与了对运动中枢疲劳的调控;大鼠力竭运动过程中,A2AR和D2DR是通过调节Thr34-DARPP-32磷酸化程度而发挥对运动疲劳的调控作用;运动至力竭时A2AR和D2DR调节作用异常,可能是运动疲劳时纹状体神经元异常兴奋的原因之一。     

低氧力竭运动对血浆心钠素和内皮素浓度的影响

目的探讨低氧条件下力竭运动对心血管调节激素血浆心钠素(ANP)、内皮素(ET-1)浓度变化的影响。方法选取8名体育学院男生进行直立蹬自行车运动试验,分别进行常氧运动(N)和低氧运动(H),测定运动至力竭的时间以及运动前(静坐10min)、运动后即刻、运动后3min、运动后30min受试者心率、血压、血浆渗透压和血浆ANP、ET-1浓度的变化。结果 (1)运动后即刻,N组血浆ANP、ET-1浓度显著升高(P<0.05),H组血浆ANP、ET-1浓度非常显著性升高(P<0.01),两组间血浆ANP和ET-1升高幅度具有显著性差异(P<0.05);(2)运动后即刻,N组和H组血浆渗透压均显著升高(P<0.05);(3)与H组相比,N组运动至力竭时间显著较长(P<0.05);(4)运动后30min,两组血浆渗透压仍显著高于安静时(P<0.05)。(5)运动后即刻,两组心率较安静时均显著升高(P<0.001),至运动后30min,心率虽然都有一定恢复,但仍显著高于安静状态(P<0.05)。结论低氧力竭运动可使心血管组织合成释放ANP、ET-1适度增加,对机体产生有益的影响。     

有氧耐力训练对青春期少年血清IGF-I 和GHBP 水平的影响

胰岛素样生长因子 I(IGF- I)和生长激素结合蛋白 (GHBP)是了解生长激素—胰岛素样生长因子(GH- IGF)轴变化的主要指标。研究测定了青春期少年中长跑运动员和普通对照组安静时和短时间递增负荷力竭运动后即刻血清 IGF- I和 GHBP的浓度。结果显示 :运动员安静时血清 IGF- I和 GHBP浓度与普通对照组相比无显著性差异 (P>0 .0 5 ) ;运动员和普通对照组短时间递增负荷力竭运动后血清IGF- I和 GHBP浓度较运动前相比均无明显变化 (P>0 .0 5 ) ;运动员血清 IGF- I和 GHBP的浓度对短时间递增负荷力竭运动的应答和普通对照组相比无显著性差异 (P>0 .0 5 )。可见 ,长期有氧耐力运动并未改变青春期少年 IGF- I和 GHBP的分泌 ,具体的机制还有待于进一步探讨     

运动性疲劳对大鼠神经肌肉接头乙酰胆碱脂酶活性的影响

目的:研究运动性疲劳对大鼠神经肌肉接头乙酰胆碱脂酶(AChE)活性的影响.方法:15只雄性SD大鼠随机按体重配对分为安静对照组、运动即刻组和运动后恢复6h组.运动即刻组和运动后恢复6h组大鼠按Bedfo rd大强度运动模型运动至力竭.所有大鼠取带神经的腓肠肌,冰冻切片,行AChE的组织化学检测.结果:力竭后即刻AChE的染色较正常对照组弱,恢复6h后AChE染色逐渐加深,但还没有恢复到安静组水平;运动性疲劳后即刻AChE的平均灰度值增加,恢复6h后AChE的平均灰度值下降,但仍然高于安静对照组,且与安静对照组比差异都具有显著性;力竭后即刻AChE阳性产物的平均截面积较安静对照组和恢复6h组比较明显减小.结论:大鼠神经肌肉接头乙酰胆碱脂酶活性的下降可能与运动性疲劳的产生有关.     

再竭运动恢复期大鼠纹状体微透析液中Glu和GABA含量的变化

目的：观察大鼠力竭运动恢复期纹状体细胞外液谷氨酸（Glu）、γ-氨基丁酸（GABA）含量的动态变化,分析它们的变化特点与相互关系,为探索运动性中枢疲劳产生和恢复机制提供实验依据。方法：将12只SD雄性大鼠随机分为安静对照组（6只）和力竭运动组（6只）,于运动后4h、5h、6h、8h、24h收集微透析样品并采用毛细管电泳一激光诱导荧光法直接进样检测。结果：力竭运动恢复期大鼠纹状体细胞外液中Glu含量高于安静水平,其恢复期变化呈先上升后下降的趋势,运动后8h达峰值,运动后24h仍显著高于安静水平（P〈0．05）;GABA含量高于安静水平,其恢复期变化呈先上升后下降的趋势,运动后6h达峰值,运动后24h仍显著高于安静水平（P〈0．05）;Glu／GABA比值显著低于安静水平（P〈0．05）,运动后24h仍显著低于安静水平（P〈0.05）。结论：运动性中枢疲劳产生时,机体同时促进Glu、GABA的释放,但是GABA释放量更高,抑制性神经递质释放占优势,通过直接通路和间接通路抑制运动。恢复期后期两者均逐渐下降,纹状体兴奋性逐渐升高,疲劳得以逐渐恢复。力竭运动恢复期大鼠纹状体细胞外液Glu、GABA含量升高及恢复均有延迟性,力竭运动后24h恢复仍未完成;大鼠纹状体细胞外Glu／GABA显著低于安静水平,24h恢复期抑制性神经递质仍起主导作用。     

6周递增负荷训练对大鼠骨骼肌IGF-I及血清GH、IGF-I水平影响的研究

生长激素(GH)、胰岛素样生长因子I(IGF-I)都是了解GH-IGF轴变化的主要指标.IGF不仅是内分泌因子,还能在组织局部起作用.通过对6周递增负荷跑台练习的大鼠进行研究,结果显示:运动后即刻,大鼠血清GH水平明显升高(P＜0.01);运动组与对照组相比,骨骼肌IGF-I水平有明显升高(P＜0.01),表明运动对骨骼肌组织内IGF的分泌有调节作用.     

长期运动训练对外周血淋巴细胞DNA损伤和凋亡的影响及机制研究

训练组(男子足球运动员,n=16)和对照组(男子大学生,n=16)在功率自行车上完成一次递增负荷力竭运动。运动前、运动后以及运动后24 h采集静脉血,测定外周血淋巴细胞计数、淋巴细胞凋亡率、羟自由基、8-羟基脱氧鸟嘌呤(8-OHdG)和8-氧鸟嘌呤DNA糖基化酶(OGG1)。结果发现,运动后即刻,训练组和对照组外周血淋巴细胞计数(P<0.01;P<0.05)、淋巴细胞凋亡率(P<0.05;P<0.01)、羟自由基(P<0.01;P<0.01)、8-OHdG(P<0.01;P<0.01)和OGG1(P<0.01;P<0.01)均高于运动前水平,而训练组OGG1升高幅度高于对照组(P<0.01),其他各指标升高幅度则均明显低于对照组(均为P<0.01)。运动后24h,对照组外周血淋巴细胞计数低于运动前(P<0.01),淋巴细胞凋亡率高于运动前(P<0.01),而训练组则恢复至运动前;两组8-OHdG(P<0.05;P<0.01)均高于运动前,但升高幅度明显低于对照组(P<0.01);OGG1在对照组恢复至运动前,而训练组仍高于运动前水平(P<0.05)。因此,长期运动训练通过降低氧化应激水平、提高DNA修复能力、减轻DNA氧化损伤,抑制运动性淋巴细胞凋亡。     

不同运动方式对绝经后女性IL-6、TNF-α和hs-CRP的影响

目的比较12周有氧运动或抗阻训练对绝经后女性白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)和高敏C-反应蛋白(hs-CRP)影响的差异,为制定特异性的运动处方提供依据。方法将符合标准的受试者随机分为有氧运动组(18人),抗阻训练组(17人)和对照组(20人)。有氧运动组和抗阻训练组进行每周3次、共12周的运动干预,对照组保持日常生活习惯不变。实验前后分别测定血清IL-6、TNF-α、hs-CRP等指标。结果 12周运动干预后,有氧运动组血清IL-6较运动前下降了13%(P<0.01),血清TNF-α(P>0.05)和hs-CRP(P>0.05)无显著性变化;抗阻训练组血清IL-6较运动前无显著性变化(P>0.05),但血清TNF-α和hs-CRP分别下降了11%(P<0.05)和26%(P<0.05)。对照组所有指标的变化不明显。相关分析显示,实验前hs-CRP基础值与BMI(r=0.36,P<0.01)、空腹血糖(r=0.23,P<0.05)和IL-6(r=0.22,P<0.01)正相关,与VO2max(r=-0.29,P<0.05)负相关;实验后hs-CRP的变化值与BMI的变化值(r=0.21,P<0.05)正相关。结论 绝经妇女慢性全身性炎症状态与其BMI、血糖水平和体内炎症因子的水平有关;12周有氧运动或抗阻训练均能有效改善绝经后女性慢性全身性炎症状态,但抗阻训练的效果优于有氧运动,其原因与BMI的改善有关。     

离心运动伴不同程度的血流限制对外周疲劳及心脏自主神经功能的效应研究

目的:探讨急性离心运动伴4种不同程度的血流限制对年轻女性外周疲劳及心脏自主神经功能的影响,综合评价各方案的安全性,为长期血流限制运动干预提供参考。方法:将40名女大学生随机分为4组,分别进行小强度抗阻(30%1RM)伴0%(CON组)、40%(BFR₄₀组)、60%(BFR₆₀组)和80%(BFR80组)动脉闭塞压(AOP)的血流限制运动。各小组进行4组伸膝离心运动,第1组重复30次,后3组重复15次,组间休息30 s。检测运动前、运动后即刻、15 min、30 min、1 h以及24 h的骨骼肌收缩性能(最大径向位移、收缩速度)、最大等长力量和心脏自主神经功能。结果:1)与CON组相比,BFR₄₀组的副交感神经活性受到轻微抑制(P<0.05),可在运动后30 min内恢复(P>0.05);2)BFR₆₀组的最大等长力量在运动后显著下降(P<0.01),副交感神经活性进一步抑制(P<0.01),交感神经支配增强(P<0.05),运动后30 min内恢复交感—副交感神经的平衡性(P>0.05);3)BFR80组运动后诱发显著的外周疲劳(P<0.01),使副交感恢复显著延迟,交感活性大幅增强(P<0.05),需更长时间恢复交感—副交感神经的平衡性(24 h内);4)相关性分析显示,副交感神经活性分别与最大径向位移(r=0.65)、收缩速度(r=0.62)和最大等长力量(r=0.55)呈正相关(P<0.05),交感神经活性与上述3个指标呈负相关(P<0.05)。结论:血流限制运动中,40%AOP会抑制迷走神经活性;60%AOP可明显影响交感神经活性和交感—副交感调控的平衡性;80%AOP可诱发显著的外周疲劳,且与心脏自主神经调控密切相关。综上所述,不建议心血管风险高的患者使用80%AOP训练。     

The influence of pre-warming on the physiological responses to prolonged intermittent exercise

To examine the influence of pre-warming on the physiological responses to prolonged intermittent exercise in ambient temperatures of 21.5?±?0.6°C and relative humidities of 35.7?±?5.4% (mean?±?s), six healthy men performed intermittent treadmill running (30-s bouts at 90% of maximal oxygen uptake separated by 30-s static recovery periods) to exhaustion after active pre-warming, passive pre-warming and pre-exercise rest (control). Exercise time to exhaustion was significantly different between all conditions (active, 51.8?±?7.2?min; passive, 38.5?±?11.1?min; control, 72.0?±?17.2?min; P <?0.05). These changes in performance time were closely associated with a significant decline in both the rate of heat storage and heat storage capacity (P <?0.05). Rectal temperature, heart rate and ratings of perceived exertion were significantly higher during exercise in the two pre-warming conditions than in the control condition (P <?0.05). Ratings of perceived exertion were also significantly higher during exercise following passive pre-warming compared with active pre-warming (P <?0.05). During exercise there were no significant differences in serum prolactin, plasma norepinephrine and plasma free fatty acid concentrations between conditions. We conclude that both active and passive pre-warming promote a reduction in prolonged intermittent exercise capacity in environmental temperatures of 21°C compared with pre-exercise rest. These performance decrements were dependent upon the mode of pre-warming and closely reflected alterations in body heat content.     

游泳训练及联合补充线粒体营养素α-硫辛酸对wistar2型糖尿病大鼠血脂代谢及脂质过氧化水平的影响

目的:观察2型糖尿病(T2DM)模型大鼠,经8周游泳训练后,血脂代谢、血清氧化应激、血糖(FBG)、胰岛素敏感性(ISI)及肝脏组织二相酶活性变化,检测联合作用方式(游泳训练及联合补充α硫辛酸)对wistarT2DM大鼠血脂代谢及脂质过氧化水平的影响,并探讨其内在影响机制。方法:实验材料wistar大鼠60只,造模完成后随机分成4组,对照组(CON);α硫辛酸(LA);游泳运动组(SEX);α硫辛酸+游泳运动组(LA+SEX),每组15只。进行游泳训练共计8周,观察各组大鼠血脂代谢水平、FBG、ISI及肝脏组织二相酶活性变化。结果:经联合作用方式可极显著性降低wistar大鼠血清总胆固醇和甘油三酯水平,降低LDL-C含量和FFA水平,提高HDL-C;在降低FBG,提高ISI作用上存在叠加效应(P<0.01),对胰岛素水平无显著性影响;在改善血清氧化应激水平作用上(降低ROS和提高SOD),存在增强作用(P<0.01);对肝脏组织二相酶的影响,在对谷胱甘肽-S-转移酶(GST)和谷胱甘肽过氧化物酶(GPX)存在增强作用,对醌氧化还原酶1(NQO-1)则无此作用。结论:联合作用方式可以有效降低血清及肝脏脂质过氧化水平,纠正血脂代谢异常,提高ISI。其保护作用可能是通过降低机体氧化应激水平,维持机体血脂正常代谢水平,减少氧化应激而实现。提示,联合作用方式可以为治疗T2DM提供新思路。     

The effects of carbohydrate supplementation during repeated bouts of prolonged exercise on saliva flow rate and immunoglobulin A

The purpose of this study was to assess the effect of carbohydrate (CHO) feeding during different periods of two 90-min cycling bouts (the first bout began at 09:00?h and the second bout began at 13:30 h) at 60% maximal oxygen uptake(VO2max) on saliva flow rate and saliva immunoglobulin A (sIgA) responses to the second exercise bout. The study consisted of three investigations: carbohydrate supplementation during (1) the first hour of the recovery interval (CHO-REC), (2) during the first bout of exercise and (3) during the second bout of exercise. Each investigation included two trials completed in a counterbalanced order and separated by at least 4 days. Participants consumed a lemon-flavoured 10% w/v carbohydrate beverage or placebo (22 ml.kg-1 body mass) in the first hour of the recovery interval (n=8) and 500 ml just before exercise, followed by 250 ml every 20 min during exercise in the first (n=9) and second exercise bouts (n=9). Timed unstimulated saliva samples were collected at 10 min before exercise, after 48-50 min of exercise and during the last 2 min of exercise, at 1 h post exercise, 2 h post exercise (first exercise bout only), and 18 h post exercise (second exercise bout only). Venous blood samples were taken 5 min before exercise and immediately after exercise for both exercise bouts in all trials. The main findings of the present study were as follows. First, carbohydrate ingestion during both exercise bouts, but not during the recovery interval, better maintained plasma glucose concentrations and attenuated the increase in plasma adrenaline and cortisol concentrations after the second exercise bout compared with placebo. Second, carbohydrate feeding had no effect on saliva flow rate and sIgA secretion rate compared with placebo. Third, saliva flow rate and sIgA concentration returned to pre-exercise bout 1 values within 2 h in all trials. Fourth, there was no delayed effect of exercise on oral immunity. These findings suggest that carbohydrate ingestion during the first or second bout of exercise, but not during the recovery interval, is likely to better maintain plasma glucose concentrations and attenuate the responses of plasma stress hormones to a second exercise bout than ingestion of fluid alone. Two bouts of 90 min cycling at 60% VO2max on the same day appears to inhibit saliva flow rate during the second exercise bout but does not alter sIgA transcytosis. Our results show that carbohydrate ingestion during any period of two prolonged exercise bouts does not induce different effects on oral immunity compared with placebo.     

The effects of carbohydrate supplementation during repeated bouts of prolonged exercise on saliva flow rate and immunoglobulin A

The purpose of this study was to assess the effect of carbohydrate (CHO) feeding during different periods of two 90-min cycling bouts (the first bout began at 09:00?h and the second bout began at 13:30?h) at 60% maximal oxygen uptake ([Vdot]O_2max) on saliva flow rate and saliva immunoglobulin A (sIgA) responses to the second exercise bout. The study consisted of three investigations: carbohydrate supplementation during (1) the first hour of the recovery interval (CHO-REC), (2) during the first bout of exercise and (3) during the second bout of exercise. Each investigation included two trials completed in a counterbalanced order and separated by at least 4 days. Participants consumed a lemon-flavoured 10% w/v carbohydrate beverage or placebo (22?ml?·?kg^?1 body mass) in the first hour of the recovery interval (n = 8) and 500?ml just before exercise, followed by 250?ml every 20?min during exercise in the first (n = 9) and second exercise bouts (n = 9). Timed unstimulated saliva samples were collected at 10?min before exercise, after 48?–?50?min of exercise and during the last 2?min of exercise, at 1?h post exercise, 2?h post exercise (first exercise bout only), and 18?h post exercise (second exercise bout only). Venous blood samples were taken 5?min before exercise and immediately after exercise for both exercise bouts in all trials. The main findings of the present study were as follows. First, carbohydrate ingestion during both exercise bouts, but not during the recovery interval, better maintained plasma glucose concentrations and attenuated the increase in plasma adrenaline and cortisol concentrations after the second exercise bout compared with placebo. Second, carbohydrate feeding had no effect on saliva flow rate and sIgA secretion rate compared with placebo. Third, saliva flow rate and sIgA concentration returned to pre-exercise bout 1 values within 2?h in all trials. Fourth, there was no delayed effect of exercise on oral immunity. These findings suggest that carbohydrate ingestion during the first or second bout of exercise, but not during the recovery interval, is likely to better maintain plasma glucose concentrations and attenuate the responses of plasma stress hormones to a second exercise bout than ingestion of fluid alone. Two bouts of 90?min cycling at 60% [Vdot]O_2max on the same day appears to inhibit saliva flow rate during the second exercise bout but does not alter sIgA transcytosis. Our results show that carbohydrate ingestion during any period of two prolonged exercise bouts does not induce different effects on oral immunity compared with placebo.     

高压氧对急性力竭性运动后血乳酸清除和肝酶谱恢复的影响

为了探讨HBO对力竭性运动后机体乳酸代谢和血清肝细胞酶的影响,让20名体育系男大学生在自行车功率计上运动至力竭,然后随机分成HBO组和对照组,他们分别在HBO和自然状态下恢复约120Min。在运动前、运动后和运动后2小时(恢复期)测定血清乳酸含量和LDB,ALAT、ALP、r-GT活力以及CG的含量。实验结果:力竭性运动后,HBO组和对照组血清LA的含量、LDH、ALAT、ALP、r-GT活力均显著升高,而血清CG含量却显著下降。恢复期,HBO组的LA含量显著低于运动后即刻(P<0.001)和运动前水平(F<0.01),并显著低于对照组(P<0.05)。恢复期与运动后比较,HBO组的血清LDH和r-GT活力均显著下降,而对照组虽有下降,但无显著性差异,虽然HBO组和对照组的ALAT活力均显著下降,但无显著性差异,虽然HBO组和对照组的ALAT活力均显著下降,但HBO组下降幅度比对照组大。实验结果提示:力竭性运动可引起机体肝细胞通透性的增加或损伤,HBO可以促进机体LA的清除和血清肝细胞酶的恢复,有利于运动疲劳的恢复。     

The effects of high-intensity intermittent exercise on saliva IgA, total protein and alpha-amylase

The aim of this study was to assess the effect of an acute bout of high-intensity intermittent exercise on saliva IgA concentration and alpha-amylase activity, since this type of training is commonly incorporated into the training programmes of endurance athletes and games players. Eight well-trained male games players took part in the study. They reported to the laboratory after an overnight fast and performed a 60-min cycle exercise task consisting of twenty 1-min periods at 100% VO2max, each separated by 2 min recovery at 30% VO2max. Unstimulated whole saliva was collected over a 5-min period into pre-weighed tubes and analysed for total protein, saliva IgA and alpha-amylase. The saliva flow rate ranged from 0.08 to 1.40 ml x min(-1) at rest and was not significantly affected by the exercise. The performance of the intermittent exercise bout did not affect the saliva IgA concentration, but caused a five-fold increase in alpha-amylase activity (P<0.01 compared with pre-exercise) and a three-fold increase in total protein concentration (P<0.01). These returned to pre-exercise values within 2.5 h post-exercise. It has been suggested that IgA concentration should be expressed as the ratio to total protein concentration, to correct for any concentrating effect due to evaporative loss of saliva water when breathing through the mouth (as in strenuous exercise). The present study clearly demonstrates that this is not appropriate, since there is an increase in salivary protein secretion rate immediately after exercise (571+/-77 microg x min(-1) compared with 218+/-71 microg x min(-1) pre-exercise; P<0.05). The increased saliva alpha-amylase activity after exercise may improve the protective effect of saliva, since this enzyme is known to inhibit bacterial attachment to oral surfaces. The saliva alpha-amylase secretion rate was lower immediately pre-exercise than at any other instant, which may have been due to anticipatory psychological stress, although the subjects were all familiar with interval exercise. This emphasizes the need for true resting non-stressed control conditions in future studies of the effects of exercise on saliva constituents.