Vigo Daniel E, Ogrinz Barbara, Wan Li, Bersenev Evgeny, Tuerlinckx Francis, Van Den Bergh Omer, Aubert André E
Departamento de Docencia e Investigación, Facultad de Ciencias Médicas, Universidad Católica Argentina, Buenos Aires.
Aviat Space Environ Med. 2012 Feb;83(2):125-30. doi: 10.3357/asem.3120.2012.
In prolonged spaceflights the effect of long-term confinement on the autonomic regulation of the heart is difficult to separate from the effect of prolonged exposure to microgravity or other space-related stressors. Our objective was to investigate whether the sleep-wake variations in the autonomic control of the heart are specifically altered by long-term confinement during the 105-d pilot study of the Earth-based Mars500 project.
Before (pre), during (T1: 30, T2: 70, andT3: 100 d), and after (post) confinement, 24-h EKG records were obtained from the six crewmembers that participated in the mission. Sleep and wake periods were determined by fitting a square wave to the data. Autonomic activity was evaluated through time and frequency domain indexes of heart rate variability (HRV) analysis during wake and sleep periods.
During confinement, wake HRV showed decreased mean heart rate and increased amplitude at all frequency levels, particularly in the very low (pre: 13.3 +/- 0.2; T1: 13.9 +/- 0.3; T2: 13.9 +/- 0.2; T3: 13.9 +/- 0.2; post: 13.2 +/- 0.2) and high (pre: 7.6 +/- 0.4; T1: 8.3 +/- 0.5; T2: 8.2 +/- 0.4; T3: 8.1 +/- 0.4; post: 7.6 +/- 0.3) frequency components (values expressed as mean +/- SE of wavelet power coefficients). Sleep HRV remained constant, while sleep-wake high frequency HRV differences diminished.
The observed autonomic changes during confinement reflect an increase in parasympathetic activity during wake periods. Several factors could account for this observation, including reduced daylight exposure related to the confinement situation.
在长时间太空飞行中，长期禁闭对心脏自主调节的影响很难与长期暴露于微重力或其他与太空相关的应激源的影响区分开来。我们的目的是在基于地球的火星500项目为期105天的初步研究中，调查长期禁闭是否会特别改变心脏自主控制中的睡眠-觉醒变化。
在禁闭前（pre）、期间（T1：30天、T2：70天和T3：100天）以及禁闭后（post），从参与任务的六名机组人员处获取24小时心电图记录。通过将方波拟合到数据中来确定睡眠和觉醒时段。在觉醒和睡眠时段，通过心率变异性（HRV）分析的时域和频域指标评估自主神经活动。
在禁闭期间，觉醒时的HRV显示平均心率降低，且在所有频率水平上振幅增加，特别是在极低频率（pre：13.3±0.2；T1：13.9±0.3；T2：13.9±0.2；T3：13.9±0.2；post：13.2±0.2）和高频（pre：7.6±0.4；T1：8.3±0.5；T2：8.2±0.4；T3：8.1±0.4；post：7.6±0.3）成分（数值表示为小波功率系数的平均值±标准误）。睡眠时的HRV保持不变，而睡眠-觉醒高频HRV差异减小。
禁闭期间观察到的自主神经变化反映出觉醒时段副交感神经活动增加。有几个因素可以解释这一观察结果，包括与禁闭情况相关的日光暴露减少。
