If Blood Is Red, Why Are Veins Blue?

Escrito por Center for Vein Restoration
Model of vascular system

Have you ever wondered why veins are blue if blood is red? We answer your questions below.

When you prick your finger, the blood gushing out is bright red. So why are the veins carrying your blood blue? Although it may seem odd to see red blood come out of blue-colored veins, it’s an optical illusion of sorts.

The reason for this phenomenon is how we visualize light and color. Different colors have different wavelengths. For example, white light contains the full spectrum of colors and wavelengths. Red light has the longest wavelength, which allows it to travel further below the skin surface where your veins are located. The red blood — or hemoglobin — in the veins absorbs the red light, so you may not see the red.

Blue light, on the other hand, doesn’t travel as far. So when white light penetrates your skin, you only see blue. In a way, your eyes are playing a trick on you. Unlike arteries, veins are closer to the skin’s surface; therefore, it’s easier for you to spot them. Healthy veins almost always appear to be blue under the skin.

Yet, there are distinct signs when your veins may be damaged and require treatment — even if they appear blue.

When to Know if Your Veins are Malfunctioning

Normally, seeing blue veins is nothing to worry about. However, changes in your veins could signal a problem with your circulation. Arteries and veins function together to circulate blood throughout your body. Arteries pump oxygenated blood to your tissues and organs from the heart. At the same time, veins carry the deoxygenated blood back to the heart to be re-oxygenated, and the process starts again.

Sometimes that system breaks down for various reasons, primarily being weakened valves in the veins that permit blood to pool. The broad medical term for this condition is venous insufficiency, although you may know it as vein disease. Vein disease is the root cause of varicose veins, swelling, leg pain and heaviness, and a host of other leg discomforts.

When your veins bulge, feel painful or heavy, itch, or cramp, it may indicate venous insufficiency. A vein specialist can examine your veins to determine what is causing your symptoms, often a backup of blood in the veins.

Although varicose veins are generally considered a cosmetic problem, those swollen veins can lead to serious complications if left untreated. As blood collects in the vein, your skin may become inflamed. As the inflammation grows, you may develop slow-healing sores, which could then become infected.

It’s always good to watch for any changes in the color of your veins. Everyone is different, and your veins may not always appear blue. But if they suddenly turn from blue to a darker blue, purple, or green, it could mean blood is collecting in your veins, or you may have developed a blood clot in the legs known as deep vein thrombosis (DVT).

How to Care for Your Veins

Although there are many minimally invasive procedures to eliminate varicose veins, you may not have to undergo treatment to maintain your vein health. Taking care of your veins begins with simple self-care tips, such as:

Exercise Regularly. Support your veins by doing exercises that contract the calf muscles, which help pump blood through the veins. Workouts such as walking, biking, and swimming are excellent for your veins. When you're inactive, the risk of having the blood pool in the veins increases.

Eat Right. Your diet affects your veins. Build your meals around leafy green vegetables, fruits packed in antioxidants (blueberries and strawberries, for example), and lean meats. Choose healthy fats such as those found in avocados, olive oil, and salmon.

Wear Compression Stockings. Highly elastic compression stockings gently squeeze the veins, so blood flows more smoothly. Compression stockings are recommended for people whose jobs have them seated or standing in one place for long hours.

Stop Smoking. If you are a non-smoker, congratulations! If you do smoke, now is the time to quit. The carbon monoxide and tar in cigarettes contribute to a narrowing of the veins, which is bad for your circulation.

Time for a Vein Checkup

Your vein health is a vital part of your overall well-being. Center for Vein Restoration physicians specialize in vascular disorders. They will evaluate your veins and recommend minimally invasive treatment options. Contact us today for an appointment.


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