We’ve all had those moments where we run into things and come away with a nasty bruise, but we will explain why some of us seem to be more resilient and heal quickly while others of us seem to wake up with mystery bruises with no memory of where they came from.

我们都有一种经历就是在撞倒一些东西之后就会出现很严重的淤青，但是我们将要解释为什么有的人似乎恢复和自愈能力很强，而像我们一样的其他人似乎不记得是怎么弄的淤伤呢。

After explaining exactly how the bruising process works and looks (for lighter skinned people, that is), the video explains that some people may bruise more easily if they’re prone to specific blood conditions like hemophilia or Von Willebrand Disease—where the blood doesn’t clot as quickly as it should or the proteins in the blood that are supposed to clot don’t work properly. Also, people who are on blood thinning medications for heart conditions or blood pressure conditions may also bruise more easily because of the way the medicine interacts with your blood. Similarly, if you’re particularly athletic or do a lot of weight training, you may be prone to bruise more often because the process of building muscle involves causing small amounts of damage to muscle tissue and then letting it heal back, stronger than before.

在解释了这些淤伤到底是如何产生以及形状之后(有的人肤色比较浅)，视频解释说一些人很容易出现淤伤的原因可能是他们特殊的血液条件比如血友病或者血管性血友病，也就是淤伤的地方的血液不能按常理很快凝结成块，或者血液中的凝血蛋白质不能正常发挥作用。而且，如果服用治疗心脏病或者血压的血液稀释药物，由于药物与血液的的相互作用，这样也就更容易出现淤伤。同理，如果你酷爱运动或者做了许多力量型练习，因为在肌肉训练过程中会导致一些肌肉组织损伤，复原之后的肌肉组织就会比以前更硬，这样也容易引起淤伤。

Beyond that though, if you do really get those mystery bruises and you have no idea where they’re from, they could be an underlying condition that you should speak to your doctor about. If none of the above applies to you, and you don’t remember bumping your shin in the middle of the night—or you do and that bruise seems to be taking forever to go away, it might be time to call the doctor.

除此以外，如果你真的经常出现莫名其妙的淤伤，而且不知道怎么回事，这或许是你身体内部隐藏的健康问题，那么你就应该告诉医生这些情况。如果上述这些都不适用于你，而且你也不记得半夜曾经撞伤，或者你记得曾经撞伤过，但是淤伤似乎一直没有恢复的样子，那你就得看医生了。