Is the thumb nail on the foot purple?

Purple nails, most people will think of cyanosis, cyanosis is caused by hypoxia (this is the biggest reason) cyanosis is a pathological phenomenon, related to the heart and lungs. As long as there is no flustered, flustered, short of breath, etc. Usually it's not a cardiopulmonary problem. If there is, we should pay attention to it.

It is cold in winter, and the hemoglobin in the blood is darker than usual. In this case, purple is normal and healthy!

Less exercise in winter, poor blood flow, more activity, enhanced blood circulation, no big problem.