Fun Facts about Veins – Blood Flow, Length, and More

Key Takeaways

• Your blood vessels stretch about 60,000 miles when laid end to end, which would wrap around the earth more than twice.
• Blood travels at roughly 3 feet per second, so one blood cell can move through your entire body in about a minute.
• Your heart moves about 2,000 gallons of blood through your veins and other blood vessels each day, or about 83 gallons an hour.
• The great saphenous vein runs from the top of your foot to your groin, which makes it the longest vein in the body and a common source of varicose veins.
• Veins look blue because of how light passes through your skin. The blood inside them is dark red.

 

How long are your veins stretched out? How long does it take for blood to circulate? What is the longest vein in the body? Why are our veins blue? How much blood does the heart pump per day through our body? These are a few of the most common questions about veins – and some of the answers may surprise you!

Why are Your Veins Blue?

Your veins look blue, but the blood inside them is always red. Blood leaving your heart through the aorta is bright red, and blood returning through the inferior vena cava, a large vein that carries deoxygenated blood from the lower body to the heart, is a darker maroon red. It all has to do with hemoglobin, the protein in red blood cells that carries oxygen. When oxygen binds to hemoglobin, blood turns bright red, and when hemoglobin releases that oxygen to your tissues, the blood becomes a deeper red.

The blue color comes from the way light passes through your skin. Red light has a longer wavelength and travels deep into your tissue, where much of it is absorbed. Blue light stays closer to the surface, so more of it bounces back out of your skin, and your eyes see the veins just under the surface as blue. Thin or lighter skin, low body fat, warm temperatures, and exercise can all make veins easier to see. Veins that bulge, twist, or ache may be varicose veins and are worth having checked by a vein specialist.

How Many Gallons of Blood Are in the Human Body?

An average adult has about 1.2 to 1.5 gallons (4.5 to 5.5 liters) of blood. Blood makes up about 7 to 8 percent of your body weight, and adult men usually have more than adult women because they are larger on average.

Blood volume also changes with age and life stage. A newborn has only about one cup of blood, and an 80-pound child has roughly 0.7 gallons. During pregnancy, blood volume can rise by as much as 50 percent to support the growing baby.

Your body only holds a gallon or so at a time, but that blood moves constantly. Your heart pumps about 2,000 gallons through your veins and other blood vessels every day, which is enough to fill five hot tubs (Arkansas Heart Hospital).

How Fast Does Blood Travel in the Body?

Traveling at roughly 3 feet per second, a blood cell in the average person travels through the entire body in about one minute. This incredible velocity moves about 83 gallons of blood an hour.

What is the Longest Vein in the Body?

The great saphenous vein is the longest in the human body. It runs from the top of your foot to your upper thigh and groin. It is also one of the most common sources of varicose veins, because blood can pool when its valves weaken.

How Far Would Your Veins Stretch if Laid Out?

If you laid all of your blood vessels end to end, including your arteries, veins, and capillaries, they would stretch about 60,000 miles (roughly 100,000 kilometers). The Earth’s equator is about 24,900 miles around, so your circulatory system could wrap around the planet almost two and a half times.

Most of that distance comes from capillaries, the tiny vessels that link your arteries to your veins. Capillaries make up about 80 percent of the network, and many are thinner than a human hair. Your veins are a smaller share of the total, but they do the hard work of pushing blood back up to your heart, often against gravity. When the valves inside your veins weaken, blood can pool and lead to varicose veins.

Your veins return blood to your heart every minute of every day, and most people never think about them until something goes wrong. Swelling, heavy or aching legs, and visible varicose or spider veins can all be signs that your veins need attention. The team at Albert Vein Institute treats these conditions with minimally invasive options such as endovenous laser ablation, radiofrequency ablation, sclerotherapy, and microphlebectomy, and most patients return to their normal routine quickly.

Contact the AVI team today to request a consultation for vein health solutions in Lone Tree and Colorado Springs.