When you stand up, why doesn't the blood in your body rush to your feet?

Question

I'm curious as to why, when you hang upside down, why does the blood rush to your head, yet it doesn't rush to your feet when you stand up? Nobody I know can answer this question; we're all stumped.

Answer 1

There's a variety of factors, really.

One, of course, is that you are designed to work standing up. Your body has a bunch of physical mechanisms to keep your blood flowing normally while you are upright. As others have mentioned, your veins are placed near the muscles in your arms and legs, so when you flex those muscles it helps push your blood against the flow of gravity (your heart doesn't do ALL the work!). That is why your legs can 'fall asleep' (or worse) on a long plane flight or if you're still for a while. There are also one-way valves in those veins so the blood can go up, but not down. But you don't have such veins or muscular help in your arteries, so hanging upside-down for a long time can stop proper circulation and actually kill you!

There is also an experiential factor involved. Compared to your feet, your face has a massive amount of nerves in it. Because of all these nerves, you can feel a lot more things in your face and head than you can with your feet. A good example is blushing. Blushing is usually caused by your heart beating a little faster... your whole body is getting a little extra blood, but you tend to only FEEL it in your face. The same thing happens if you hang upside-down: you quickly feel the extra blood because of all those nerves, but unless you've got a face on your feet you won't feel the same when you right yourself.

Hope that helps!

Answer 2

That is not true that the blood does not rush towards the feet when we stand...it ofcourse does. It is the valves(flaps) present in the veins that prevents the backflow of blood. The very answer can be experienced as well. When we stand for a short span of time the legs don't ache but if we stand continuosly for an hour or so, the pain sets in.......thats when the threshold of the valves is reached i.e. the gravitational force overpowers and the blood rushes down making them feet heavy and painful.

Answer 3

The human body is replete with valves, sphincters, peristalsis and reflexive neuro-muscular activities, and of course the usual constant of mobility inertia drawn from movement we provide by having reasonably conditioned bodies, all of which factors address this. All is tuned and timed, each with its coordinate.

These valves and sphincters in concert with the brain are neurologically and physiologically signatured to counteract such forces as the law of gravity but as well work in concert with this same law.

Gravity provides a considerable conditioning or grounding on which the progressions of blood circulation depends, without which grounding the rhythmical precisions would have no foundation to support the continuous interface of blood flow and pulse with valves and sphincters, else everything would fly out of control. In other words, using a picture here, we could not walk if we did not have a solid counter surface to, say, step off to each next step...

In our case, the counter surface in the body's stead would be the gravity itself in coordination with the valves and sphincters to perform against the inert directional flow of blood. The body simply abides natural laws and as such enjoys certain dichotomies -- and, say, it has its own secretive dialectic, which one might say is an antagonism, which ensures precise motion between resistant and non-resistant forces occur and ensures that the circulatory system is kept in lock-step to avert otherwise malfunctions such as what your question poses.

Answer 4

The blood does rush towards your feet but you have valves in your veins to prevent backflow. When you stand up and flex your calf muscles they squeeze on the viens in your legs to help blood circulate throughout your body instead of pooling in your feet.

Answer 5

Your heart is closer to your head, and has a massive artery pumping blood up to it. Your brain needs more blood and oxygen to operate. if you add oxygen gravity causes overkill.

As for you legs, it is farther away, so you body has to do more work to pump blood down there. When you move your muscle contract and the blood in your legs is moved back up to your heart to receive more oxygen. that's why if you're in a car and don't move your legs they will hurt (not enough blood), your legs will fall asleep. Gravity helps to get the blood down there.

Just think about what is most important to your body, head(brain), your internal organs (torso), and then your limbs.

the blood moves more quickly in and out of your head.
more slowly to your feet.

veins- bring blood back to the heart, it is blood without oxygen blue blood, it moves back to your heart by you moving.

arteries pump blood out from your heart to your body, red blood with oxygen.