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目的本实验利用头低位卧床模拟失重,通过观察和比较30 d卧床期间不同体育锻炼方式对心脏收缩泵血功能的影响,旨在进一步明确体育锻炼对失重后心脏功能变化的对抗效果,为制定我国载人航天时航天员失重对抗方案提供实验依据。方法15名男性健康被试者,随机分为对照组、下肢肌力训练组和自行车功率计训练组3组,每组5人。对照组仅-6°HDT卧床30 d,不进行任何处理,下肢肌力训练组和自行车功率计训练组在30 d卧床期间分别进行下肢肌力训练和自行车功率计训练。实验期间测量心脏收缩泵血功能的变化。结果对照组左室射血时间在卧床第22、26天较卧床前显著降低(P<0.05),射血分数在第26天显著性降低(P<0.05),每搏量、心输出量在第1天显著降低(P<0.05)。下肢肌力训练组左室射血时间在卧床期间较卧床前均显著降低(P<0.05),每搏量除第5、7天外均显著降低(P<0.05),心输出量在第1、30天显著降低(P<0.05)。自行车功率计训练组心脏收缩功能指标在卧床期间均无明显变化,每搏量、心输出量在卧床第1天较卧床前显著降低(P<0.05)。结论30 d头低位卧床可引起心脏收缩泵血功能下降,下肢肌力训练和自行车功率计训练可在一定程度上改善心血管功能,其中自行车功率计训练的对抗效果更佳。
Objective This experiment simulated the weightlessness of the head-lying bedridden by observing and comparing the effects of different physical exercises during the 30-day stay on the systolic blood pump function in order to further clarify the antagonistic effect of physical exercise on cardiac function changes after weightlessness. The spacecraft astronauts lose weight countermeasures program to provide experimental evidence. Methods Fifteen male healthy subjects were randomly divided into control group, lower limb muscle strength training group and bicycle power meter training group, with 5 in each group. In the control group, only -6 ° HDT was placed in bed for 30 days without any treatment. The lower limb muscle strength training group and the bicycle power meter training group were respectively trained in lower limb muscle strength and bicycle power meter during the 30-day stay in bed. Measurement of cardiac systolic blood pump function during the experiment. Results The left ventricular ejection time of the control group decreased significantly (P <0.05) on the 22nd and 26th days of bed rest and the ejection fraction decreased significantly on the 26th day (P <0.05). The stroke volume and cardiac output were Day 1 significantly decreased (P <0.05). Left ventricular ejection time in lower limb strength training group was significantly lower than that in bed before bed rest (P <0.05), stroke volume was significantly lower than that on day 5 and 7 (P <0.05) 30 days significantly reduced (P <0.05). Cycling power meter training group cardiac systolic function index in the bed without significant changes, stroke volume, cardiac output in bed 1 day significantly lower than before bedtime (P <0.05). CONCLUSION: The low bed rest for 30 days may cause cardiac systolic blood pump function decline. Lower extremity muscle strength training and bicycle power meter training can improve cardiovascular function to a certain extent. Among them, the bicycle power meter training has a better antagonistic effect.