After a far too short night, you are told that you look bad and for good reason, you have beautiful dark circles under your eyes! But then, why do we have dark circles when we are tired?
Before talking about the causes and why of dark circles, let’s start at the beginning: what is a dark circle? A dark circle corresponds to a variation in the color of the skin located below the eye. Often, the ring has a blue/purple color.
You should know that the region under the eye is highly vascularized. It consists of a network of blood vessels and lymphatic vessels, these two networks are involved in skin circulation.
As far as blood vessels are concerned, there are both arteries, which carry blood from the heart to the organs, and veins, which bring the blood used by the organs back to the heart. In the arteries, the circulating blood is red, because it is rich in oxygen. On the contrary, the blood circulating in the veins (which has been consumed by the organs) is bluish, because it is poor in oxygen.
In parallel, the lymphatic vessels circulate the lymph. Lymph is a biological fluid that has a composition similar to blood plasma, it transports white blood cells or lymphocytes and evacuates waste from cells. Along its journey through the lymph vessels, the lymph collects certain waste products, bacteria and damaged cells so that they can be flushed out of the body or destroyed by the lymph nodes (“waste sorting centre”). Once rid of this “waste”, the lymph returns to the venous system.
All this vascular network is located under an ultrathin skin. Indeed, the skin around the eyes is much thinner than on the rest of the body. It measures approximately 0.3 mm, or the thickness of only three sheets of printer paper. By comparison, it averages 0.6mm on the body and can reach 1.2-4.7mm on the palms and soles.
It is therefore translucent and thus allows the blood vessels to be seen through transparency… Thus, a disturbance in the level of blood circulation will be directly visible at the level of the skin.
Yes, dark circles are therefore the visible manifestation of a disruption of the cutaneous circulation!
As you know, quality sleep is essential. It is particularly essential for skin circulation. Indeed, during the night, our skin goes into regeneration mode: circulation is activated and reaches its maximum in order to repair the skin and rid it of cellular waste, bacteria, excess water…
In case of fatigue, the latter becomes lazy and slows down… Thus, on the one hand, the veins fill up with blood and therefore dilate (become bigger). On the other hand, the poor lymphatic circulation prevents good drainage (good elimination) of the waste that accumulates. Dark circles appear!
Be careful, however, if lack of sleep remains a major cause of the appearance of dark circles, other factors should not be overlooked…
Surprisingly, the problem of dark circles can be hereditary: if several members of your family are prone to dark circles, it could be that, despite getting enough sleep, dark circles are not doing you any favors!
Finally, aging will not help matters. Indeed, over time, the skin loses elasticity and becomes thinner, leaving the blood vessels even more visible.
Nevertheless, you can act on dark circles with simple gestures, in particular by relaunching the cutaneous circulation. For example, applying cold to dark circles can help reduce dark circles that are already present. Indeed, the cold stimulates blood circulation and thus has a decongestant effect: the blood vessels retract and the dark circle is less visible.
*Coralie Thieulin, research professor in physics at ECE, doctor in biophysics, ECE Paris.