Schlegel-University of Waterloo Research Institute for Aging, 250 Laurelwood Drive, Waterloo, Ontario, N2J OE2, Canada.
Trento Institute for Fundamental Physics and Applications (TIFPA), National Institute of Nuclear Physics (INFN), University of Trento, Via Sommarive 14, 38123 Povo, Trento, Italy.
Nat Rev Cardiol. 2018 Mar;15(3):167-180. doi: 10.1038/nrcardio.2017.157. Epub 2017 Oct 20.
National space agencies and private corporations aim at an extended presence of humans in space in the medium to long term. Together with currently suboptimal technology, microgravity and cosmic rays raise health concerns about deep-space exploration missions. Both of these physical factors affect the cardiovascular system, whose gravity-dependence is pronounced. Heart and vascular function are, therefore, susceptible to substantial changes in weightlessness. The altered cardiovascular function in space causes physiological problems in the postflight period. A compromised cardiovascular system can be excessively vulnerable to space radiation, synergistically resulting in increased damage. The space radiation dose is significantly lower than in patients undergoing radiotherapy, in whom cardiac damage is well-documented following cancer therapy in the thoracic region. Nevertheless, epidemiological findings suggest an increased risk of late cardiovascular disease even with low doses of radiation. Moreover, the peculiar biological effectiveness of heavy ions in cosmic rays might increase this risk substantially. However, whether radiation-induced cardiovascular effects have a threshold at low doses is still unclear. The main countermeasures to mitigate the effect of the space environment on cardiac function are physical exercise, antioxidants, nutraceuticals, and radiation shielding.
国家太空机构和私营公司的目标是在中长期内延长人类在太空的存在。与目前不太理想的技术一起，微重力和宇宙射线对深空探索任务的健康提出了担忧。这两个物理因素都影响着心血管系统，心血管系统对重力的依赖性很强。因此，心脏和血管功能在失重状态下容易发生实质性变化。在太空中改变的心血管功能会在飞行后期间导致生理问题。受损的心血管系统容易受到空间辐射的过度影响，从而导致协同作用下的损伤增加。空间辐射剂量明显低于接受放射治疗的患者，在胸部区域接受癌症治疗后，放射治疗的患者的心脏损伤已有充分的记录。尽管如此，流行病学研究结果表明，即使辐射剂量很低，患晚期心血管疾病的风险也会增加。此外，宇宙射线中重离子的特殊生物学效应可能会大大增加这种风险。然而，辐射诱导的心血管效应是否在低剂量下存在阈值仍不清楚。减轻太空环境对心脏功能影响的主要对策是体育锻炼、抗氧化剂、营养保健品和辐射屏蔽。
