Why Are Veins Blue?
Kids are full of curiosity, and they constantly question how the world works. Unfortunately, adults who chose careers outside of the sciences often find themselves stumped. When it comes to explaining how airplanes fly, why plants are green, and why you can see the moon during the day (sometimes), the answer is often “I don’t know”. It gets a little embarrassing.
The expert vein doctors at the Vein Treatment Clinic can’t prepare you for every tough question, but we do know the answer to this one: “If blood is red, why are veins blue?” Astonish your friends and wow your kids by explaining this amazing optical illusion.
The Extraordinary Circulatory System
Every cell in your body needs oxygen to function, and blood is responsible for making sure it gets to every nook and cranny. Blood flows through an intricate network of vessels, which include arteries, capillaries, and veins. If all of the blood vessels in a human body were stretched out end-to-end, they would be between 60,000 and 100,000 miles long. For perspective, the circumference of the Earth is just 24,901 miles at the equator.
The heart takes care of keeping your blood moving. It pumps blood to the lungs, where your red blood cells pick up oxygen. The addition of oxygen turns blood bright red. Oxygenated blood travels through arteries to various muscles, organs, and tissues. Arteries connect with tiny capillaries. Inside the capillaries, blood drops off the oxygen, picks up carbon dioxide, then moves through the capillaries to the veins. The veins bring deoxygenated blood back to the heart.
Deoxygenated blood is a darker shade of red than oxygenated blood, but it is certainly not blue. Blood is always red. So, the question remains. Why are veins blue?
A Little Bit About Light
Understanding a bit about light helps to answer the question, “Why are veins blue?” Light travels at different wavelengths, depending on the color. Wavelengths of light range from approximately 700 nanometers to approximately 400 nanometers. Red light travels at a wavelength of approximately 700 nanometers. At the opposite end of the spectrum, violet light travels at just 400 nanometers. Other colors fall somewhere in between. Blue light is on the shorter side at approximately 475 nanometers.
The next point to consider is that light has to travel through your skin for your veins to be visible. Because red light has longer wavelengths, it can travel farther beneath your skin. It is absorbed by the blood cells it encounters there, and not much is reflected back. Blue light has shorter wavelengths, so it doesn’t travel as far. It is more easily disrupted, and more is reflected back by your skin.
When white light, which is a mixture of all colors, shines on your skin, some of it hits the veins that are close to the surface. The red light is absorbed by the veins, and the blue light is reflected back. So, compared to your skin, your veins appear blue. However, this is an optical illusion. When veins are not covered by skin, they are actually dark red.
More Circulatory System Trivia
“Why are veins blue?” is just one of thousands of questions you can ask about the marvelous, mysterious circulatory system. These are a few more remarkable features:
Artery walls are tougher than the walls of your veins. They have to be, because they withstand the pressure of blood pushed through by a powerful heartbeat. Veins are more delicate, because blood is moving through them with less force. However, they do face an obstacle: gravity. Veins have to carry blood from the lower half of your body to the heart, and they must fight gravity to do it.
Veins have an intricate system of one-way valves that guide blood towards the heart and prevent backflow. Unfortunately, these valves can become damaged through injury or disease, and then the trouble starts. When valves don’t work properly, blood leaks backwards, and it begins to pool in your legs and ankles. This sets off a chain reaction of uncomfortable and potentially dangerous symptoms.
The most visible issue occurs when pooling blood causes unsightly varicose veins and spider veins. If left untreated, vein disease may cause aching or heaviness in the legs. Some people experience sudden, sharp leg cramps, and others develop restless leg syndrome. In serious cases, skin discoloration occurs and patients become prone to sores and cysts that are difficult to treat.
Fortunately, a specialized vein doctor in NY or vein doctor in NJ can help when you face issues with your hardworking circulatory system. Vein disease can be treated with minimally invasive procedures that close off unhealthy veins and reroute blood through other, healthier vessels.
If you have symptoms of vein disease, speak with a vein doctor in New York or vein doctor in New Jersey to learn more about the treatments available to you. You can schedule your consultation by phone or online with just a few clicks.