Functional Impact of 10 Days of Bed Rest in Healthy Older Adults

Background. Many older individuals decline functionally during hospitalization, and the deleterious consequences of bed rest may be one cause. This study reports on the effect of 10 days of bed rest on multiple functional parameters in healthy older adults. Methods. Healthy older men and women (n = 11, 67 +/- 5 years old) remained on bed rest for 10 days continuously, and consumed a eucaloric diet providing the Recommended Dietary Allowance for protein. Measures of lower extremity strength and power, aerobic capacity and physical performance, as well as physical activity were performed before and after bed rest. Results. All measures of lower extremity strength were significantly lower after bed rest including isotonic knee extensor strength (-13.2 +/- 4.1%, p = .004) and stair-climbing power (-14 +/- 4.1%, p = .01). Maximal aerobic capacity was 12% lower after bed rest (p = .04). whereas measures of physical performance (Short Physical Performance Battery, and a live-item physical performance test) were not significantly different. Voluntary physical activity decreased after bed rest, and the percentage of time spent inactive increased (7.6 +/- 1.8%, p =.004). There were no medical complications. Conclusions. In healthy older adults, 10 days of bed rest results in a substantial loss of lower extremity strength, power, and aerobic capacity, and a reduction in physical activity, but has no effect on physical performance. Identification of interventions to maintain muscle function during hospitalization or periods of bed rest in older adults should be a high priority.