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Some injuries and illnesses require that a person remain in bed and immobile until he is better. Not only can this be emotionally difficult for a person, especially one who is typically very active, it can also take a toll on the body. Each system is affected differently by a long period of immobility.


The cardiovascular system is responsible for transporting your blood through your body to bring oxygen and nutrients to all of the parts of your body. When you are immobile, your heart must work harder to do its job than if you were active. The risk of a clot forming in your blood stream, potentially blocking off crucial operations in your body, is higher when you are no longer active. In addition, the lack of movement slows down your circulation in general as blood vessels use the action of muscles to help move blood through your body.


You might think your respiratory system would have an easier time when you are not active. However, this is not the case. Fluid has a higher probability of building up in your lungs when you are immobile because your muscles are not working to remove excess fluid from your body. Your breathing also becomes more shallow, resulting in areas of your lungs no longer being used. When this happens, those areas that are no longer used may collapse and become useless. This also results in less oxygen/carbon dioxide exchange in your lungs.


The muscles and skeletal system in your body are one of the areas of the body most affected by immobility. When you do not use your muscles, they begin to weaken and deteriorate. The muscles also are shortened because they are not being used. They begin to lose their flexibility. Your bones also begin to lose their density because a lack of pressure on the bones reduces the amount of calcium that they absorb. This is why many people who suffer a condition that results in immobility, whether it is whole-body immobility or just one part, such as a broken arm, must go through physical therapy when they are healed.


The way your body feels is affected by prolonged periods of immobility. When you are immobile for a longer period of time, your body consistently experiences pressure on certain parts of your body. That pressure will begin to cause pain, but over time you will notice new sensations, such as tingling, and eventually feel nothing at all. You may also experience unusual spasms within the nerves.


Digestion is also effected by immobility, especially in instances where you cannot take in food in the normal fashion. The decrease in activity will also decrease your appetite, thus causing you to eat less. The digestive system also slows down, resulting in food being digested more slowly. This can cause fecal impaction and constipation.


The genitourinary system is responsible for keeping the fluid levels in your body correct. When you are immobile, the system becomes less effective, causing your body to retain more fluids. The risks of bladder infection and kidney stones also increase with immobility. When you are immobile, all of your muscles weaken, including those in your bladder. This can cause incomplete voiding, which contributes to the increased risk of bladder infection.


Metabolism is the part of the endocrine system that controls how food is digested, among other things. The metabolism slows down considerably when you are immobilized. This can cause the electrolytes in your body to become unbalanced, which can cause problems throughout your body. The exchange of gases and nutrients within your body is also affected by a change in metabolism. Some of the side effects of these metabolism changes include nausea, indigestion and gas.


Your skin makes up the integumentary system and can be negatively impacted by immobilization. Bed sores are a common side effect of being unable to move from your bed. Any place that has consistent pressure is at risk for these sores. Any sores or other cuts of the skin take longer to heal when your body is immobile. Swelling is also an issue for those who are immobile, mainly caused by the increase in fluid in the body because of the inefficiencies of the genitourinary system.