These restrictions did have a reasonable basis. Observation had shown that injuries heal faster if the injured part is rested. The key to the treatment of fractures is that the broken bone is immobilised in a plaster cast; injured muscles and cuts in the skin heal faster and with less scarring if the arm or leg is kept still. Surely, doctors reasoned, a heart damaged by a coronary thrombosis, a lung damaged by tuberculosis, and the uterus after childbirth will heal faster and with less scarring if the whole body is put to rest.
So why has bed rest gone out of fashion? The answer is simple: it is too dangerous, especially for the sick. After an operation and during sickness, the blood clots more easily. Keeping someone in bed slows the circulation, and the blood stagnates in the veins deep inside the legs and pelvis. Blood clots form in these deep veins, and fragments may then be carried into the heart and lungs, where they become trapped - a pulmonary embolism. A big one may stop the heart. As many as a third of hospital patients examined after death have had a recent pulmonary embolism, and it is the main cause of death in many of these. In the days of prolonged bed rest, pulmonary embolism caused the deaths each year of thousands of patients recovering from minor operations and minor heart attacks - as well as healthy women recovering from childbirth.
Rest in bed, if prolonged beyond a week or so, leads to wasting of the muscles and thinning of the bones. It lowers morale and causes insomnia and constipation. And yet the underlying rationale - that it promotes healing - remains true. But rest can be nearly as complete while the patient is encouraged to walk around, keeping the blood gently circulating and the muscles in use. So the trend has been to get patients out of bed as soon as possible - and the optimum length of stay has been determined by comparing large numbers of patients treated by various periods of bed rest in hospital. Surgeons have experimented to find which operations can be done on an outpatient basis and how soon inpatients may be sent home.
These studies have led to very substantial shortenings in the average time people stay in hospital. The 'improvements in productivity' have a sound medical basis as well as cheering up administrators and politicians. What has gone is the tradition of invalidism that encouraged many young people with chronic illness to educate themselves by spending months lying in bed reading.