A Combined Hot and Hypoxic Environment during Maximal Cycling Sprints Reduced Muscle Oxygen Saturation: A Pilot Study
A Combined Hot and Hypoxic Environment during Maximal Cycling Sprints Reduced Muscle Oxygen Saturation: A Pilot Study
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DOI：
10.52082/jssm.2021.684
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发表时间：
2021-12-01
影响因子：
3.2
通讯作者：
Goto, Kazushige
中科院分区：
文献类型：
--
作者：
Yamaguchi, Keiichi;Imai, Tomohiro;Goto, Kazushige
本研究探讨了高温和低氧复合环境对重复15s最大骑行冲刺时肌肉氧合的影响。在一项单盲交叉研究中，9名训练有素的短跑运动员在常氧(NOR；23摄氏度，50%，FiO(2)20.9%)、常压低氧(HYP；23摄氏度，FiO(2)14.5%)和高温常压低氧(HH；35摄氏度，FiO(2)14.5%)环境下进行了3次15-S的最大自行车冲刺，中间穿插7分钟的被动恢复。在所有试验中，相对湿度都被设置为50%。采用近红外光谱分析技术评价运动过程中股外侧肌的氧合情况。同时监测氧摄取量(VO2)和动脉血氧饱和度(SpO(2))。三种情况下的峰值或平均功率输出没有显著差异。在第二次冲刺中，HH组(-17.0+/-2.7%)的组织饱和度指数的下降明显大于HYP组(-10.4+/-2.8%)(p<；0.05)。HYP(VO2=980+/-52mL/min，Spo(2)=82.9+/-0.8%)和HH(VO2=965+/-42mL/min，Spo(2)=83.2+/-1.2%)条件下的平均VO2和SpO(2)显著低于NOR(VO2=1149+/-40mL/min，Spo(2)=90.6+/-1.4%；p<；0.05)。综上所述，尽管HH和HYP之间存在等量的低氧应激，但在第二轮的三次15-S极限自行车短跑比赛中，HH组的肌肉血氧饱和度下降幅度大于HYP组。
The present study investigated the effects of a combined hot and hypoxic environment on muscle oxygenation during repeated 15s maximal cycling sprints. In a single-blind, cross-over study, nine trained sprinters performed three 15-s maximal cycling sprints interspersed with 7-min passive recovery in normoxic (NOR; 23 degrees C, 50%, FiO(2) 20.9%), normobaric hypoxic (HYP; 23 degrees C, FiO(2) 14.5%), and hot normobaric hypoxic (HH; 35 degrees C, FiO(2) 14.5%) environments. Relative humidity was set to 50% in all trials. The vastus lateralis muscle oxygenation was evaluated during exercise using near-infrared spectroscopy. The oxygen uptake (VO2) and arterial oxygen saturation (SpO(2)) were also monitored. There was no significant difference in peak or mean power output among the three conditions. The reduction in tissue saturation index was significantly greater in the HH (-17.0 +/- 2.7%) than in the HYP (-10.4 +/- 2.8%) condition during the second sprint (p < 0.05). The average VO2 and SpO(2) were significantly lower in the HYP (VO2 = 980 +/- 52 mL/min, SpO(2) = 82.9 +/- 0.8%) and HH (VO2 = 965 +/- 42 mL/min, SpO(2) = 83.2 +/- 1.2%) than in the NOR (VO2 = 1149 +/- 40 mL/min, SpO(2) = 90.6 +/- 1.4%; p < 0.05) condition. In conclusion, muscle oxygen saturation was reduced to a greater extent in the HH than in the HYP condition during the second bout of three 15-s maximal cycling sprints, despite the equivalent hypoxic stress between HH and HYP.