Rest cure

Bed rest, also referred to as the rest-cure, is a medical treatment in which a person lies in bed for most of some period of time to cure an illness. Bed rest refers to voluntarily lying in bed as a treatment, and not being confined to bed because of a health impairment which physically restricts a person from leaving the bed. The practice is still commonly used for an array of conditions although a 1999 systematic review found no benefits for any of the 17 conditions studied, and no proven benefit for any conditions at all, beyond that imposed by symptoms.

Even though most patients in hospitals spend most of their time in the hospital beds, bed rest more often refers to an extended period of recumbency at home. In the United States, nearly 20% of pregnant women have some degree of restricted activity prescribed at some point during pregnancy despite the growing volume of data showing it to be dangerous, causing some experts to call its use "unethical".

While studies show that extended bed rest has not been proven to have beneficial effects for any condition, it does have some temporary benefit in certain localized injuries such as:

Bed rest continues to be commonly prescribed in certain cases:

It makes sense that by resting and keeping the uterus horizontal, you can help to decrease contractions and give the sources of bleeding a chance to heal. It has been shown that females with uterine problems benefit from this procedure, but only if it is not done in excess of 3 days.

Prolonged bed rest has long been known to have deleterious physiological effects, such as muscle atrophy and other forms of deconditioning such as arterial constriction. Besides lack of physical exercise it was shown that another important factor is that the hydrostatic pressure (caused by gravity) acts anomalously, resulting in altered distribution of body fluids. In other words, when getting up, this can cause an orthostatic hypertension, potentially inducing a vasovagal response. Additionally, prolonged bed rest can lead to the formation of skin pressure ulcers. Even physical exercise in bed fails to address certain adverse effects.

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Wikipedia