# Heart pumping and body wieght

1. Jul 20, 2009

### ATPenergy

When the heart pump and blood flow down the body , Does the body wieght increase,be the same or decrease? Why?

Last edited: Jul 20, 2009
2. Jul 20, 2009

### negitron

It is not possible for the heart to pump blood downwards without pumping an exactly equal amount upwards.

3. Jul 20, 2009

### ATPenergy

Ok. Let's pump blood upwards also

4. Jul 20, 2009

### negitron

Well, since the momentum of the blood being pumped downwards is necessarily identical in magnitude to the momentum of the blood being pumped in the opposite direction, then net effect is zero and therefor your weight remains the same.

5. Jul 20, 2009

### ATPenergy

Does the body has momentum upwards?

6. Jul 20, 2009

### Staff: Mentor

Negitron just answered that question "no" (zero).

7. Jul 20, 2009

### maverick_starstrider

Equal and opposite reactions. Like birds flying in the back of a mach truck. It makes no difference, the weight remains constant.

8. Jul 21, 2009

### Capt. McCoy

EXACTLY what negitron said!!!

9. Jul 21, 2009

### Naty1

According to relativity, pressure,energy and mass all have a gravitational effect...So body weight would increase as the heart pumps but not enough for us to actually measure... In practice any such gain would be more than offset by the calories consumed pumping....
Rapidly moving blood also has kinetic energy; not so easy a question to answer but I'm pretty sure the next effect is a loss in "weight".

By analogy, compressing a spring means it has potential energy stored...hence it's weight increases just a tiny,tiny,bit...in that case the energy is clearly added to the system unlike the example with a heart burning calories(energy).

Assuming the volume of blood does not change there is no net effect of blood being pumped up or down...this could be of interest since gravity at the head is less than at the feet.

10. Jul 21, 2009

### maverick_starstrider

Probably not the answer the OP was looking for...