2000 Steps/Day Does Not Fully Protect Skeletal Muscle Health in Older Adults during Bed Rest

摘要

Physical activity in an inpatient setting is often limited to brief periods of walking. For healthy adults, public health agencies recommend a minimum of 150 min/week of moderate intensity exercise. We sought to determine if meeting this activity threshold, in the absence of incidental activities of daily living, could protect skeletal muscle health during bed rest. Healthy older adults (68 ± 2 y) were randomized to 7-days bed rest with (STEP; n=7) or without (CON; n=10) a 2000 step/day intervention. Performing 2018 ± 4 steps/day did not prevent the loss of lean leg mass and had no beneficial effect on aerobic capacity, strength or muscle fiber volume. However, the insulin response to an oral glucose challenge was preserved. Performing a block of 2000 steps/day, in the absence of incidental activities of daily living, was insufficient to fully counter the catabolic effects of bed rest in healthy older adults.