Dose-response relationship between exercise duration and enhanced function and cognition in acutely hospitalized older adults: A secondary analysis of a randomized clinical trial

Abstract

Exercise may reverse functional decline in hospitalized older adults, but the optimal duration is unclear. This study examined the potential relationship between in-hospital multicomponent exercise program duration and changes on physical function, cognition and muscle function to maximize exercise-related health benefits in acutely hospitalized older patients. This secondary analysis of a multicenter randomized controlled trial examined the relationship between duration of an in-hospital multicomponent exercise program and changes in physical function, cognition, and muscle strength in 570 acutely hospitalized older adults. Participants completed 3, 4, or 5-7 consecutive days of exercise based on the progression of their acute medical illness. The acute clinical condition of the older patients was similar across the study groups (i.e., 3/4/5-7 days) at admission. Outcomes included the Short Physical Performance Battery (SPPB) for functional capacity, Gait Velocity Test for gait speed, handgrip for muscle strength, and cognitive tests. Of the 570 patients included in the analysis, 298 were women (52.3%) and the mean(SD) age was 87.3(4.8) years. Exercise groups increased SPPB scores compared to controls, with gains of 1.09 points after 3 days, 1.97 points after 4 days, and 2.02 points after 5-7 days (p<0.001). The 4-day program showed the greatest benefit for functional capacity. Gait velocity increased by 0.11 m/s after 4 and 5-7 days (p=0.032). Similar dose-response relationships were seen for handgrip strength and cognition, with 5-7 days showing greater gains than 3 days(p<0.05). Multicomponent exercise programs enhance physical and cognitive function in hospitalized older adults, regardless of exercise dosage. A four-day program significantly boosts functional capacity, while 5-7 days improves handgrip strength and cognition, highlighting the importance of exercise dosage in countering functional decline. Implementing evidence-based inpatient exercise prescriptions can help reverse muscle weakness and improve cognitive and physical function.