Autonomic cardiovascular and respiratory control during prolonged spaceflights aboard the International Space Station
Autonomic cardiovascular and respiratory control during prolonged spaceflights aboard the International Space Station
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DOI：
10.1152/japplphysiol.00137.2007
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发表时间：
2007-07-01
影响因子：
3.3
通讯作者：
Tank, Jens
中科院分区：
文献类型：
--
作者：
Baevsky, Roman M.;Baranov, Victor M.;Tank, Jens
自主神经控制受损是长期航天飞行中的心血管危险因素。很少有关于血压（BP）、心率（HR）和心率变异性（HRV）在长时间太空飞行期间和之后的报道。我们检验了心血管控制在长时间太空飞行中保持稳定的假设。在长期任务（飞行时间为162-196天）期间，对8名男性宇航员（年龄41-50岁，体重指数为22-28 kg/m（2））的心电图、光电容积描记术和呼吸频率（RF）进行了评估。在飞行前60天和30天，飞行期间每4周，以及飞行后第3天和第6天，在自主呼吸和控制呼吸期间进行记录。飞行前和飞行后进行直立性测试。飞行期间RF、BP降低（P < 0.05）。平均心率和心率变异性在低和高频段没有改变在航天飞行。然而，个人的反应是不同的，并与飞行前的值。脉搏波传导时间随飞行时间延长而缩短（P < 0.05）。在控制呼吸（6次呼吸/分钟）期间，6名宇航员的HRV下降，1名宇航员在飞行期间增加。HR、BP和HRV的最显著变化发生在着陆后。飞行过程中血压和射频的下降与稳定的心率和心率变异性相结合，表明功能性适应，而不是病理性变化。在我们的研究中，脉搏波传导时间的缩短是令人惊讶的，可能反映了心输出量在空间上的重新分布。控制呼吸（6次/分）时HRV降低表明副交感神经储备减少，这可能导致飞行后干扰。
Impaired autonomic control represents a cardiovascular risk factor during long-term spaceflight. Little has been reported on blood pressure (BP), heart rate (HR), and heart rate variability (HRV) during and after prolonged spaceflight. We tested the hypothesis that cardiovascular control remains stable during prolonged spaceflight. Electrocardiography, photoplethysmography, and respiratory frequency (RF) were assessed in eight male cosmonauts (age 41-50 yr, body-mass index of 22-28 kg/m(2)) during long-term missions (flight lengths of 162-196 days). Recordings were made 60 and 30 days before the flight, every 4 wk during flight, and on days 3 and 6 postflight during spontaneous and controlled respiration. Orthostatic testing was performed pre- and postflight. RF and BP decreased during spaceflight (P < 0.05). Mean HR and HRV in the low- and high-frequency bands did not change during spaceflight. However, the individual responses were different and correlated with preflight values. Pulse-wave transit time decreased during spaceflight (P < 0.05). HRV reached during controlled respiration (6 breaths/min) decreased in six and increased in one cosmonaut during flight. The most pronounced changes in HR, BP, and HRV occurred after landing. The decreases in BP and RF combined with stable HR and HRV during flight suggest functional adaptation rather than pathological changes. Pulse-wave transit time shortening in our study is surprising and may reflect cardiac output redistribution in space. The decrease in HRV during controlled respiration (6 breaths/min) indicates reduced parasympathetic reserve, which may contribute to postflight disturbances.