如果人的血液太过黏稠，就会使血压增高，损害血管，增加心脏病发作的风险。据美国物理学家组织网6月8日（北京时间）报道，美国天普大学物理学家最近发现，利用磁场可降低人类血液黏度。研究论文发表在近日出版的《物理评论E辑》上。
目前，稀释血液的唯一方法是利用阿司匹林等药物，但这些药会带来副作用。曾发明过用电场或磁场降低发动机或管道中油脂黏度这一方法的天普大学教授陶荣家（音译）将这种方法推广到血液黏度的控制中，通过测试大量血液样本后发现，利用磁场也可稀释人类循环系统中的血液。
因为红细胞含铁，施加磁场能将红血细胞极化，使它们以短链、流线运动的形式连在一起，由于这些短链比单个的血细胞要大，它们向着中心流下来时，与血管壁的摩擦就会减少。这种连接效果降低了血液黏度，有助于它们更加顺畅地流动。给血液施加一个1.3特斯拉的磁场约1分钟，就能将血液黏稠度降低20%到30%，且这个强度只相当于核磁共振成像的磁场强度。当磁场被移开时，血液在血管中会慢慢恢复为原来的黏稠状态，但这要经过几个小时。
“通过选择合适的磁场强度和脉冲时间，我们就能控制红细胞聚集成链的大小，由此控制血液黏度。这种磁流变的方法提供了一个有效的途径，能在可选择的范围内控制血液黏度。”陶荣家解释说，这种方法不仅安全，还可重复，可以通过多次施加磁场的方式来降低血液黏度，而且黏度降低并不影响红细胞的正常功能。
陶荣家还表示，该方法仍需要进一步研究，以此为基础能最终开发出一种预防心脏病发作的新疗法。
总编辑圈点：
吃得越来越好、运动越来越少，使很多人不得不为自己越来越黏的血液发愁。实际上，利用磁场影响血黏度并不算是新研究，只是陶小组施加1.3T磁场1分钟，降低血黏度20%以上的数据着实给力。而血液中富含铁、磁场能将铁极化都是常识，这也再次说明，很多科技进步往往来自于一些简单的原理。不过，说阿司匹林是稀释血液的唯一方法未免武断——献血对降低血黏度同样有效。因此，与其等到血黏度增高后再大把吃药，不如现在就参与无偿献血，利人利己。
生物探索推荐原文出处：
Magnetic Field Can Reduce Blood Viscosity
If a person's blood becomes too thick it can damage blood vessels and increase the risk of heart attacks. But a Temple University physicist has discovered that he can thin the human blood by subjecting it to a magnetic field.
Rongjia Tao, professor and chair of physics at Temple University, has pioneered the use of electric or magnetic fields to decrease the viscosity of oil in engines and pipelines. Now, he is using the same magnetic fields to thin human blood in the circulation system.
Because red blood cells contain iron, Tao has been able to reduce a person's blood viscosity by 20-30 percent by subjecting it to a magnetic field of 1.3 Telsa (about the same as an MRI) for about one minute.
Tao and his collaborator tested numerous blood samples in a Temple lab and found that the magnetic field polarizes the red blood cells causing them to link together in short chains, streamlining the movement of the blood. Because these chains are larger than the single blood cells, they flow down the center, reducing the friction against the walls of the blood vessels. The combined effects reduce the viscosity of the blood, helping it to flow more freely.
When the magnetic field was taken away, the blood's original viscosity state slowly returned, but over a period of several hours.
"By selecting a suitable magnetic field strength and pulse duration, we will be able to control the size of the aggregated red-cell chains, hence to control the blood's viscosity," said Tao. "This method of magneto-rheology provides an effective way to control the blood viscosity within a selected range."
Currently, the only method for thinning blood is through drugs such as aspirin; however, these drugs often produce unwanted side effects. Tao said that the magnetic field method is not only safer, it is repeatable. The magnetic fields may be reapplied and the viscosity reduced again. He also added that the viscosity reduction does not affect the red blood cells' normal function.
Tao said that further studies are needed and that he hopes to ultimately develop this technology into an acceptable therapy to prevent heart disease.
Tao and his former graduate student, Ke "Colin" Huang, now a medical physics resident in the Department of Radiation Oncology at the University of Michigan, are publishing their findings in the journal Physical Review E.
