If someone is bedridden for a long time or if a body part can't be moved because of a cast, the bone mass of that area decreases. Lower mass makes bones brittle and increases the likelihood of breakage. This condition, known as disuse osteopenia, afflicts millions of people from injured children to astronauts.
Inactivity or immobilization of a body part leads to disuse osteopenia.
Why It Happens
Anytime you are inactive for an extended period, your bones release calcium and lose mass. Usually, your body naturally restores this mass once you’re active again. However, if you remain inactive for a long time, bone degeneration can become more pronounced, causing osteopenia.
Who Gets Disuse Osteopenia
People who experience prolonged bed rest and astronauts exposed to microgravity environments can develop general osteopenia. Localized osteopenia develops in injured extremities when they are confined in a cast for lengthy periods.
The best way to regenerate bone mineral density is to restore normal activity and to exercise the affected area. It is also important to maintain a healthy diet that contains high levels of calcium and vitamin D.
While disuse osteopenia is reversible, the time it takes for recovery often lasts much longer than the period of disuse and resulting bone loss. It is important to go slow when recovering to avoid injury.
Disuse osteopenia is distinct from the more serious condition of osteoporosis. For more information about osteopenia and osteoporosis, consult the World Health Organization article in the Resources below.