Final answer:
Fluids move from the lower body to the upper body in conditions such as edema due to pooling of blood in the veins of the lower limbs when standing still. The skeletal muscle pump normally counteracts gravity but fails during prolonged inactivity, thus compression garments and movement can help prevent this.
Step-by-step explanation:
Fluids moving away from the lower body to the upper body, resulting in "puffy faces" and "bird legs", is commonly related to the condition known as edema. This condition occurs when blood pools in the lower extremities, increasing the pressure within veins and promoting the leakage of fluids out of the capillaries into the surrounding tissues.
The skeletal muscle pump is an important mechanism which helps to counteract the force of gravity on the veins in the lower body. As leg muscles contract during activities such as walking or running, they exert pressure on nearby veins, pushing blood upward by opening valves superior to the contracting muscles while valves inferior close to prevent backflow. However, when there is prolonged standing without muscle contractions, blood can pool in the veins leading to increased pressure and causing fluid to move into the interstitial spaces, which may result in swollen legs or feet, and a redistribution of fluids to the upper body, producing a 'puffy' face appearance.
One method of preventing this fluid accumulation is the use of elastic bandages or compression stockings that provide external pressure to assist the veins in moving blood back up to the heart. Ensuring movement and avoiding long periods of immobility, such as walking during long-haul flights or flexing leg muscles periodically while standing, are also recommended to mitigate the potential for edema.