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Guillaume Costalat Jeremy Coquart Ingrid Castres Fabrice Joulia Olivier Sirost Eric Clua 《Journal of sports sciences》2017,35(7):678-687
We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO2]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO2) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (?0.86 bpm.%?1) while HR kinetics in NDs steadily decreased throughout BH (?0.47 bpm.%?1). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P < 0.05). As a result, BHDs showed a [tHb] drop that NDs did not at the end of BH (?7.3 ± 3.2 vs. ?3.0 ± 4.7%, respectively; P < 0.05). The most striking finding of the present study was that BHDs presented an increase in oxygen-conserving efficiency due to substantial shifts in both cardiac and peripheral haemodynamics during simulated BH. In addition, the kinetic-based approach we used provides further credence to the concept of an “oxygen-conserving breaking point” in the human diving response. 相似文献
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肌氧含量的相对有效下降值与最大摄氧量的对比研究 总被引：4，自引：0，他引：4
采用近红外无损肌氧监测系统，对赛艇运动员在递增强度运动时骨骼肌组织中肌氧的变化进行监测，测定不同运动员的肌氧含量相对有效下降值（Deff），并测定最大摄氧量（VO2max）。将监测到的Deff与VO2max的变化作对比研究，以期探讨骨骼肌组织中肌氧含量的相对变化与VO2max的变化规律及相关关系。研究结果显示运动中肌氧含量的相对有效下降值与最大摄氧量存在相关性，这为用无损伤技术监测人体运动时氧化代谢能力提供了新的途径。 相似文献
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Yi-Hung Liao Toby Mündel Yan-Ting Yang Chen-Chan Wei Shiow-Chwen Tsai 《Journal of sports sciences》2019,37(16):1805-1815
The purpose of this study was to examine CHO ingestion on a cognitive task using a field-simulated time-trial (TT) under hypoxia in well-trained triathletes. Ten male triathletes (age: 22.1 ± 1.1 years; VO2max: 59.4 ± 1.4 ml/kg/min) participated in this double-blind/crossover/counter-balanced design study. Participants completed 3 TT trials: 1) normoxic placebo (NPLA; FiO2 = 20.9%), 2) hypoxic placebo (HPLA; FiO2 = 16.3%), and 3) hypoxic CHO (HCHO; 6% CHO provided as 2 ml/kg/15 min; FiO2 = 16.3%). During the TT, physiological responses (SpO2, HR, RPE, and blood glucose/lactate), cognitive performance, and cerebral haemodynamics were measured. Hypoxia reduced TT performance by ~3.5–4% (p < 0.05), but CHO did not affect TT performance under hypoxia. For the cognitive task, CHO slightly preserved exercise-induced cognitive reaction speed but did not affect response accuracy during hypoxic exercise. However, CHO did not preserve the decreased Hb-Diff (cerebral blood flow, CBF) and increased HHb in the prefrontal lobe (p < 0.05) during hypoxic exercise, and CHO failed to preserve hypoxia-suppressed prefrontal CBF and tissue oxygen saturation. In conclusion, the present study demonstrates that CHO is effective in sustaining reaction speed for a cognitive task but not promoting TT performance during hypoxic exercise, which would be important for strategy-/decision-making when athletes compete at moderate high-altitude. 相似文献
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应用近红外光谱技术(NIRS)测定肌肉递增强度工作时肌氧含量变化与最大摄氧量和无氧阈指标之间的关系;分析肌氧拐点与无氧阈拐点产生的机制及在测定最大有氧能力中的作用。方法:受试者17名按运动水平分为A、B两组在功率自行车上以逐级递增负荷蹬车,测定右股外侧肌肌氧含量并同步测量VE、VCO2、VO2、HR,并在每级负荷末测定血乳酸。结果:研究发现递增负荷运动时肌氧含量呈台阶状下降,负荷较低时,肌氧在负荷开始阶段迅速下降之后保持平衡或升高,负荷较高时肌氧持续下降,肌氧的变化与血容量相吻合。肌氧含量与摄氧量、心率及血乳酸等值高度相关(P<0.01)。肌氧下降时出现拐点与乳酸阈、通气阈拐点基本一致。结论:研究表明NIRS测定动态肌肉收缩时肌氧含量变化对运动强度具有较高敏感性;肌氧拐点与通气无氧阈、心率无氧阈、乳酸阈在时间和强度上相一致,表明肌氧含量的测定可以用于人体最大有氧能力的评定。 相似文献
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目的:探讨急性低氧环境下递增负荷运动时肌氧含量的变化。方法:通过无损伤近红外光谱学技术(NIRS)监测11名优秀男子自行车运动员常氧和急性低氧下进行递增负荷运动时肌氧含量和心肺系统功能的变化。结果:1)低氧运动时,无氧阈(VT)和最大摄氧量(VO2max)出现时对应的心率、指动脉血氧饱和度(SpO2)、气体代谢和功率均下降,显著低于常氧运动时的值;2)低氧环境下,从开始运动到75%最大功率,Δ[HbO2]降低、Δ[HHb]增高;由75%至100%最大功率时,Δ[HbO2]保持不变,而Δ[HHb]和Δ[THb]增加;在4个不同功率等级下低氧Δ[HbO2]均显著高于常氧值,Δ[HHb]在50%、75%和100%最大功率时均显著低于常氧对应值。结论:1)男子自行车运动员低氧下运动时低氧通气反应高于常氧水平,说明提高自行车运动员在高原训练时的低氧通气反应有利于提高其有氧能力,进而提高运动成绩。2)低氧运动时Δ[HbO2]高于常氧值,Δ[HHb]低于常氧值,提示肌氧含量是反映肌肉疲劳程度的敏感指标。 相似文献
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目的:研究高水平公路自行车运动员急性低氧运动时肌氧饱和度特征。方法:采用交叉设计,通过无损近红外光谱学技术(NIRS)连续监测17名优秀公路自行车运动员常氧和低氧(模拟3 200 m,FIO2～14.0%)急性递增负荷运动时肌氧饱和度、心肺功能及通气指标的变化。结果:1)在4个不同功率等级低氧Δ[O2Hb]均显著高于常氧对应值,Δ[HHb]在50%、75%和100%最大功率时均显著低于常氧对应值,而Δ[THb]在各相对功率等级时无显著性差异。2)低氧时通气无氧阈(VT)和最大摄氧量(.VO2max)对应的HR、SpO2和Power皆显著低于常氧对应值。低氧时VT和.VO2max对应的低氧通气指标(V.E/V.O2、.VE/V.CO2)皆显著高于常氧对照值。结论:反映心血管系统与肌肉代谢耦联的低氧通气反应(HVR)是肌氧饱和度变化的基础,是肌氧饱和度反映肌肉代谢疲劳的重要生理机制。而提高运动员高原低氧时的HVR是提高其耐缺氧能力的基础,是进而提高有氧能力和运动成绩的关键。 相似文献
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递增负荷运动肌肉氧含量的变化 总被引：9，自引：0，他引：9
利用无损的近红外光谱学技术(NIRS),连续监测15名中长跑运动员以及10名非运动员在递增负荷运动时,大腿股外侧肌的肌氧含量的变化,同时监测血容量、血乳酸和心率的变化.结果显示肌氧含量与运动强度、运动能力、血容量、心率和血乳酸有密切的相关关系.肌氧含量的变化可以作为一项无损、敏感的指标直观地揭示运动时肌氧输送与消耗利用的关系. 相似文献
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近红外光谱法快速测定六味地黄丸中水分含量 总被引：1，自引：0，他引：1
采集不同厂家不同批号六味地黄丸样品的近红外光谱图,将其经First Derivative+MSC预处理,采用Savitzky-Golay平滑法(5点3阶数据平滑)处理,以滤去噪声,在7 819~4 038 cm-1谱段范围内,选择前10个主因子数,利用偏最小二乘法建立六味地黄丸的近红外光谱与药典参考方法测得的水分含量之间的相关模型。建立的水分定量校正模型相关系数R2=0.990 4,内部交叉验证均方差(RMSECV)=0.250 2,预测均方差(RMSEP)=0.099 7,平均回收率为100.75%。本实验所建模型性能较好,对六味地黄丸中水分含量有很好的预测能力,可实现大批量样品的快速检测,对中药制剂的质量分析有一定的参考价值。 相似文献
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Application of near-infrared spectroscopy to predict sweetpotato starch thermal properties and noodle quality 总被引：2，自引：0，他引：2
Sweetpotato starch thermal properties and its noodle quality were analyzed using a rapid predictive method based on near-infrared spectroscopy （NIRS）. This method was established based on a total of 93 sweetpotato genotypes with diverse genetic background. Starch samples were scanned by NIRS and analyzed for quality properties by reference methods. Results of statistical modelling indicated that NIRS was reasonably accurate in predicting gelatinization onset temperature （To） （standard error of prediction SEP=2.014 ℃, coefficient of determination RSQ=0.85）, gelatinization peak temperature （Tp） （SEP=-1.371 ℃, RSQ=0.89）, gelatinization temperature range （Tr） （SEP=2.234 ℃, RSQ=0.86）, and cooling resistance （CR） （SEP=0.528, RSQ=0.89）. Gelatinization completion temperature （To）, enthalpy of gelatinization （△H）, cooling loss （CL） and swelling degree （SWD）, were modelled less well with RSQ between 0.63 and 0.84. The present results suggested that the NIRS based method was sufficiently accurate and practical for routine analysis of sweetpotato starch and its noodle quality. 相似文献
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